S5720 and S6720 Series Ethernet Switches
V200R011C10
Configuration Guide - MPLS
Issue
10
Date
2019-12-30
HUAWEI TECHNOLOGIES CO., LTD.
Copyright © Huawei Technologies Co., Ltd. 2019. All rights reserved.
No part of this document may be reproduced or transmitted in any form or by any means without prior
written consent of Huawei Technologies Co., Ltd.
Trademarks and Permissions
and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.
All other trademarks and trade names mentioned in this document are the property of their respective
holders.
Notice
The purchased products, services and features are stipulated by the contract made between Huawei and
the customer. All or part of the products, services and features described in this document may not be
within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements,
information, and recommendations in this document are provided "AS IS" without warranties, guarantees
or representations of any kind, either express or implied.
The information in this document is subject to change without notice. Every effort has been made in the
preparation of this document to ensure accuracy of the contents, but all statements, information, and
recommendations in this document do not constitute a warranty of any kind, express or implied.
Huawei Technologies Co., Ltd.
Address:
Huawei Industrial Base
Bantian, Longgang
Shenzhen 518129
People's Republic of China
Website:
https://e.huawei.com
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Configuration Guide - MPLS
About This Document
About This Document
Intended Audience
This document is intended for network engineers responsible for switch
configuration and management. You should be familiar with basic Ethernet
knowledge and have extensive experience in network deployment and
management.
Symbol Conventions
The symbols that may be found in this document are defined as follows.
Symbol
Description
Indicates a potentially hazardous
situation which, if not avoided, could
result in equipment damage, data loss,
performance deterioration, or
unanticipated results.
NOTICE is used to address practices
not related to personal injury.
Supplements the important
information in the main text.
NOTE
NOTE is used to address information
not related to personal injury,
equipment damage, and environment
deterioration.
Command Conventions
The command conventions that may be found in this document are defined as
follows.
Convention
Description
Boldface
The keywords of a command line are in boldface.
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Convention
Description
Italic
Command arguments are in italics.
[]
Items (keywords or arguments) in brackets [ ] are
optional.
{ x | y | ... }
Optional items are grouped in braces and separated
by vertical bars. One item is selected.
[ x | y | ... ]
Optional items are grouped in brackets and
separated by vertical bars. One item is selected or
no item is selected.
{ x | y | ... }*
Optional items are grouped in braces and separated
by vertical bars. A minimum of one item or a
maximum of all items can be selected.
[ x | y | ... ]*
Optional items are grouped in brackets and
separated by vertical bars. Several items or no item
can be selected.
&<1-n>
The parameter before the & sign can be repeated 1
to n times.
#
A line starting with the # sign is comments.
Interface Numbering Conventions
Interface numbers used in this manual are examples. In device configuration, use
the existing interface numbers on devices.
Security Conventions
●
●
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Password setting
–
To ensure device security, use ciphertext when configuring a password
and change the password periodically.
–
The switch considers all passwords starting and ending with %^%#, %#
%#, %@%@ or @%@% as ciphertext and attempts to decrypt them. If
you configure a plaintext password that starts and ends with %^%#, %#
%#, %@%@ or @%@%, the switch decrypts it and records it into the
configuration file (plaintext passwords are not recorded for the sake of
security). Therefore, do not set a password starting and ending with %^
%#, %#%#, %@%@ or @%@%.
–
When you configure passwords in ciphertext, different features must use
different ciphertext passwords. For example, the ciphertext password set
for the AAA feature cannot be used for other features.
Encryption algorithms
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Configuration Guide - MPLS
About This Document
The switch currently supports the 3DES, AES, RSA, SHA1, SHA2, and MD5.
3DES, RSA, and AES are reversible, whereas SHA1, SHA2, and MD5 are
irreversible. Using the encryption algorithms DES , 3DES, RSA (RSA-1024 or
lower), MD5 (in digital signature scenarios and password encryption), or
SHA1 (in digital signature scenarios) is a security risk. If protocols allow, use
more secure encryption algorithms, such as AES, RSA (RSA-2048 or higher),
SHA2, or HMAC-SHA2.
An irreversible encryption algorithm must be used for the administrator
password. SHA2 is recommended for this purpose.
●
Personal data
Some personal data (such as MAC or IP addresses of terminals) may be
obtained or used during operation or fault location of your purchased
products, services, features, so you have an obligation to make privacy policies
and take measures according to the applicable law of the country to protect
personal data.
●
Mirroring
The terms mirrored port, port mirroring, traffic mirroring, and mirroring in this
document are mentioned only to describe the product's function of
communication error or failure detection, and do not involve collection or
processing of any personal information or communication data of users.
●
Reliability design declaration
Network planning and site design must comply with reliability design
principles and provide device- and solution-level protection. Device-level
protection includes planning principles of dual-network and inter-board duallink to avoid single point or single link of failure. Solution-level protection
refers to a fast convergence mechanism, such as FRR and VRRP. If solutionlevel protection is used, ensure that the primary and backup paths do not
share links or transmission devices. Otherwise, solution-level protection may
fail to take effect.
Reference Standards and Protocols
To obtain reference standards and protocols, log in to Huawei official website,
search for "standard and protocol compliance list", and download the Huawei SSeries Switch Standard and Protocol Compliance List.
Disclaimer
●
This document is designed as a reference for you to configure your devices. Its
contents, including web pages, command line input and output, are based on
laboratory conditions. It provides instructions for general scenarios, but does
not cover all use cases of all product models. The examples given may differ
from your use case due to differences in software versions, models, and
configuration files. When configuring your device, alter the configuration
depending on your use case.
●
The specifications provided in this document are tested in lab environment
(for example, a certain type of cards have been installed on the tested device
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About This Document
or only one protocol is run on the device). Results may differ from the listed
specifications when you attempt to obtain the maximum values with multiple
functions enabled on the device.
●
In this document, public IP addresses may be used in feature introduction and
configuration examples and are for reference only unless otherwise specified.
Product Software Versions Matching NMS Versions
The product software versions matching NMS versions are as follows.
S1720, S2700, S5700, and
S6720 Product Software
Version
NMS
V200R011C10
eSight V300R008C00 (not matching the
S1720)
iManager U2000 V200R017C50 (only
matching the S1720-10GW-2P-E)
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Contents
Contents
About This Document................................................................................................................ ii
1 MPLS Features Supported in This Version......................................................................... 1
2 MPLS Basics............................................................................................................................... 4
2.1 Overview of MPLS................................................................................................................................................................... 4
2.2 Understanding MPLS............................................................................................................................................................. 5
2.2.1 Basic MPLS Architecture.................................................................................................................................................... 5
2.2.2 MPLS Label.............................................................................................................................................................................7
2.2.3 LSP Setup................................................................................................................................................................................ 9
2.2.4 MPLS Forwarding.............................................................................................................................................................. 11
2.2.5 LSP Connectivity Check................................................................................................................................................... 16
2.3 Application Scenarios for MPLS....................................................................................................................................... 18
2.3.1 MPLS VPN............................................................................................................................................................................ 18
2.3.2 MPLS TE................................................................................................................................................................................ 19
2.3.3 MPLS 6PE............................................................................................................................................................................. 20
3 Static LSP Configuration......................................................................................................22
3.1 Overview of Static LSPs...................................................................................................................................................... 22
3.2 Licensing Requirements and Limitations for Static LSPs.........................................................................................23
3.3 Default Settings for Static LSPs....................................................................................................................................... 25
3.4 Creating Static LSPs............................................................................................................................................................. 26
3.4.1 Configuring LSR ID............................................................................................................................................................ 26
3.4.2 Enabling MPLS.................................................................................................................................................................... 27
3.4.3 Establishing a Static LSP................................................................................................................................................. 27
3.4.4 Verifying the Static LSP Configuration....................................................................................................................... 29
3.5 Configuring Static BFD for Static LSPs.......................................................................................................................... 29
3.5.1 Configuring BFD with Specific Parameters on the Ingress Node......................................................................30
3.5.2 Configuring BFD with Specific Parameters on the Egress Node....................................................................... 31
3.5.3 Verifying the Configuration of Static BFD for Static LSPs................................................................................... 33
3.6 Verifying the LSP Connectivity......................................................................................................................................... 34
3.7 Configuration Examples for Static LSPs........................................................................................................................ 35
3.7.1 Example for Configuring Static LSPs.......................................................................................................................... 35
3.7.2 Example for Configuring Static BFD to Monitor Static LSPs.............................................................................. 40
4 MPLS LDP Configuration..................................................................................................... 48
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4.1 Overview of MPLS LDP....................................................................................................................................................... 49
4.2 Understanding MPLS LDP.................................................................................................................................................. 49
4.2.1 Basic Concepts of LDP..................................................................................................................................................... 49
4.2.2 LDP Working Mechanism............................................................................................................................................... 50
4.2.2.1 LDP Messages and Process......................................................................................................................................... 50
4.2.2.2 LDP Session Setup..........................................................................................................................................................51
4.2.2.3 LDP LSP Setup................................................................................................................................................................. 53
4.2.3 Coexistent Local and Remote LDP Session...............................................................................................................57
4.2.4 LDP Security Mechanisms.............................................................................................................................................. 58
4.2.5 LDP Extensions for Inter-Area LSPs............................................................................................................................. 60
4.2.6 LDP Reliability..................................................................................................................................................................... 62
4.2.6.1 Overview of LDP Reliability........................................................................................................................................ 62
4.2.6.2 BFD for LDP LSP............................................................................................................................................................. 62
4.2.6.3 Synchronization Between LDP and IGP.................................................................................................................. 64
4.2.6.4 LDP FRR............................................................................................................................................................................. 66
4.2.6.5 LDP GR............................................................................................................................................................................... 69
4.3 Summary of MPLS LDP Configuration Tasks.............................................................................................................. 70
4.4 Licensing Requirements and Limitations for MPLS LDP..........................................................................................72
4.5 Default Settings for MPLS LDP........................................................................................................................................ 74
4.6 Configuring Basic Functions of MPLS LDP................................................................................................................... 75
4.6.1 Configuring the LSR ID.................................................................................................................................................... 75
4.6.2 Enabling Global MPLS .................................................................................................................................................... 76
4.6.3 Enabling Global MPLS LDP............................................................................................................................................ 76
4.6.4 Configuring LDP Sessions............................................................................................................................................... 77
4.6.5 (Optional) Configuring an LDP Transport Address................................................................................................78
4.6.6 (Optional) Configuring Timers for LDP Session..................................................................................................... 79
4.6.7 (Optional) Configuring the PHP Feature.................................................................................................................. 84
4.6.8 (Optional) Configuring an LDP Label Advertisement Mode.............................................................................. 85
4.6.9 (Optional) Configuring LDP to Automatically Trigger the Request in DoD Mode.....................................86
4.6.10 (Optional) Configuring LDP Loop Detection......................................................................................................... 87
4.6.11 (Optional) Configuring MPLS MTU.......................................................................................................................... 88
4.6.12 (Optional) Configuring the MPLS TTL Processing Mode.................................................................................. 90
4.6.13 (Optional) Configuring the LDP Label Policies.....................................................................................................91
4.6.14 (Optional) Disabling a Device from Distributing Labels to Remote Peers................................................. 93
4.6.15 (Optional) Configuring a Policy for Triggering LDP LSP Establishment...................................................... 94
4.6.16 (Optional) Configuring Delayed Transmission of Label Withdraw Messages........................................... 95
4.6.17 (Optional) Enabling LDP to Maintain a Session After Receiving Error TCP Packets............................... 96
4.6.18 Verifying the Configuration of Basic MPLS LDP Functions...............................................................................96
4.7 Configuring LDP Extensions for Inter-Area LSPs........................................................................................................ 97
4.8 Configuring Static BFD to Detect an LDP LSP............................................................................................................ 98
4.8.1 Configuring BFD with Specific Parameters on the Ingress Node......................................................................99
4.8.2 Configuring BFD with Specific Parameters on the Egress Node.....................................................................101
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4.8.3 Verifying the Configuration of Static BFD for LDP LSPs....................................................................................102
4.9 Configuring Dynamic BFD for LDP LSPs.....................................................................................................................103
4.9.1 Enabling Global BFD Capability................................................................................................................................. 103
4.9.2 Enabling MPLS to Dynamically Establish BFD Sessions.................................................................................... 104
4.9.3 Configuring the Triggering Policy of Dynamic BFD for LDP LSP.................................................................... 104
4.9.4 (Optional) Adjusting BFD Parameters..................................................................................................................... 105
4.9.5 Verifying the Configuration of Dynamic BFD for LDP LSPs............................................................................. 106
4.10 Configuring Synchronization Between LDP and IGP........................................................................................... 107
4.10.1 Enabling Synchronization Between LDP and IGP.............................................................................................. 107
4.10.2 (Optional) Blocking Synchronization Between LDP and IS-IS on an Interface.......................................109
4.10.3 (Optional) Setting the Hold-down Timer Value................................................................................................110
4.10.4 (Optional) Setting the Hold-max-cost Timer Value.........................................................................................111
4.10.5 (Optional) Setting the Delay Timer Value...........................................................................................................113
4.10.6 Verifying the Configuration of Synchronization Between LDP and IGP.................................................... 114
4.11 Configuring LDP FRR...................................................................................................................................................... 114
4.12 Configuring LDP GR........................................................................................................................................................ 117
4.13 Configuring LDP Security Mechanisms.....................................................................................................................119
4.13.1 Configuring LDP MD5 Authentication...................................................................................................................120
4.13.2 Configuring LDP Keychain Authentication.......................................................................................................... 121
4.13.3 Configuring the LDP GTSM....................................................................................................................................... 123
4.13.4 Verifying the Configuration of LDP Security Mechanisms............................................................................. 123
4.14 Configuring Non-labeled Public Network Routes to Be Iterated to LSPs.....................................................124
4.15 Maintaining MPLS LDP.................................................................................................................................................. 124
4.15.1 Resetting LDP................................................................................................................................................................. 125
4.15.2 Clearing LDP Statistics................................................................................................................................................ 125
4.15.3 Monitoring the LDP Running Status...................................................................................................................... 125
4.15.4 Verifying the LSP Connectivity................................................................................................................................. 126
4.15.5 Enabling the MPLS Trap Function........................................................................................................................... 127
4.16 Configuration Examples for MPLS LDP.................................................................................................................... 135
4.16.1 Example for Configuring Local LDP Sessions......................................................................................................135
4.16.2 Example for Configuring Remote MPLS LDP Sessions.................................................................................... 139
4.16.3 Example for Configuring Coexistent Local and Remote LDP Session........................................................ 143
4.16.4 Example for Configuring Automatic Triggering of a Request for a Label Mapping Message in DoD
Mode.............................................................................................................................................................................................. 151
4.16.5 Example for Configuring a Policy for Triggering LDP LSP Establishment on the Ingress and Egress
Nodes............................................................................................................................................................................................. 158
4.16.6 Example for Configuring a Policy for Triggering LDP LSP Establishment on the Transit Node........ 163
4.16.7 Example for Disabling Devices from Distributing LDP Labels to Remote Peers.....................................168
4.16.8 Example for Configuring Static BFD to Detect LDP LSPs............................................................................... 177
4.16.9 Example for Configuring Dynamic BFD to Detect LDP LSPs......................................................................... 183
4.16.10 Example for Configuring Synchronization Between LDP and IGP.............................................................189
4.16.11 Example for Configuring LDP GR......................................................................................................................... 196
4.16.12 Example for Configuring Manual LDP FRR....................................................................................................... 201
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4.16.13 Example for Configuring Auto LDP FRR............................................................................................................. 206
4.16.14 Example for Configuring an LDP Inbound Policy............................................................................................ 215
4.16.15 Example for Configuring LDP Authentication.................................................................................................. 220
4.16.16 Example for Configuring LDP GTSM................................................................................................................... 226
4.16.17 Example for Configuring LDP Extension for Inter-Area LSP........................................................................ 230
4.17 Troubleshooting MPLS LDP.......................................................................................................................................... 237
4.17.1 LDP Session Alternates Between Up and Down States...................................................................................237
4.17.2 LDP Session Is Down................................................................................................................................................... 238
4.17.3 LDP LSP Alternates Between Up and Down States.......................................................................................... 239
4.17.4 LDP LSP Is Down........................................................................................................................................................... 239
4.17.5 Inter-Area LSP Fails to Be Established................................................................................................................... 240
4.18 FAQ About MPLS.............................................................................................................................................................. 240
4.18.1 What Information Needs to Be Collected If an MPLS LDP Session Fails to Be Established?............. 240
4.18.2 The Two Ends of an LSP Are Up and Can Send Hello Messages, but the Peer End Cannot Receive
Them. Why?................................................................................................................................................................................. 241
5 MPLS QoS Configuration................................................................................................... 242
5.1 Overview of MPLS QoS.................................................................................................................................................... 242
5.2 Understanding MPLS QoS............................................................................................................................................... 243
5.2.1 MPLS DiffServ................................................................................................................................................................... 243
5.2.2 MPLS DiffServ Tunnel Modes......................................................................................................................................245
5.3 Application of MPLS QoS in the VPN Service........................................................................................................... 248
5.4 Licensing Requirements and Limitations for MPLS QoS.......................................................................................250
5.5 Default Settings for MPLS QoS......................................................................................................................................252
5.6 Configuring the Mapping of the Precedence in the Public MPLS Tunnel Label........................................... 254
5.6.1 Creating a DiffServ Domain and Configuring Priority Mapping.....................................................................254
5.6.2 Setting the Priority Mapping for the Public Tunnel............................................................................................ 255
5.7 Setting the DiffServ Mode Supported by MPLS VPNs........................................................................................... 256
5.7.1 Setting the DiffServ Mode Supported by MPLS L3VPN..................................................................................... 256
5.7.2 Setting the DiffServ Mode Supported by MPLS L2VPN..................................................................................... 257
5.7.3 Verifying the Configuration of the DiffServ Mode Supported by MPLS VPNs.......................................... 260
5.8 Configuration Examples for MPLS QoS...................................................................................................................... 260
5.8.1 Example for Configuring MPLS QoS (L3VPN).......................................................................................................260
5.8.2 Example for Configuring MPLS QoS (L2VPN).......................................................................................................271
6 MPLS TE Configuration...................................................................................................... 282
6.1 Overview of MPLS TE........................................................................................................................................................ 283
6.2 Understanding MPLS TE.................................................................................................................................................. 284
6.2.1 Basic Concepts of MPLS TE..........................................................................................................................................284
6.2.2 Implementation............................................................................................................................................................... 290
6.2.3 Information Advertisement......................................................................................................................................... 292
6.2.4 Path Calculation.............................................................................................................................................................. 300
6.2.5 CS-LSP Setup.................................................................................................................................................................... 303
6.2.5.1 Overview of CR-LSP Setup........................................................................................................................................303
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6.2.5.2 Setup of Dynamic CR-LSPs....................................................................................................................................... 304
6.2.5.3 Maintenance of Dynamic CR-LSPs........................................................................................................................ 307
6.2.5.4 RSVP-TE Messages....................................................................................................................................................... 309
6.2.6 Traffic Forwarding.......................................................................................................................................................... 313
6.2.7 Tunnel Reoptimization.................................................................................................................................................. 315
6.2.8 MPLS TE Security............................................................................................................................................................ 315
6.2.9 MPLS TE Reliability......................................................................................................................................................... 319
6.2.9.1 Overview of MPLS TE Reliability............................................................................................................................ 319
6.2.9.2 Make-Before-Break..................................................................................................................................................... 320
6.2.9.3 RSVP Hello..................................................................................................................................................................... 322
6.2.9.4 CR-LSP Backup.............................................................................................................................................................. 323
6.2.9.5 TE FRR............................................................................................................................................................................. 328
6.2.9.6 SRLG................................................................................................................................................................................. 335
6.2.9.7 TE Tunnel Protection Group..................................................................................................................................... 336
6.2.9.8 BFD for MPLS TE.......................................................................................................................................................... 339
6.2.9.9 RSVP GR.......................................................................................................................................................................... 342
6.3 MPLS TE Application on an IP MAN............................................................................................................................ 344
6.4 Summary of MPLS TE Configuration Tasks............................................................................................................... 347
6.5 Licensing Requirements and Limitations for MPLS TE.......................................................................................... 353
6.6 Default Settings for MPLS TE......................................................................................................................................... 356
6.7 Configuring a Static MPLS TE Tunnel.......................................................................................................................... 357
6.7.1 Enabling MPLS TE........................................................................................................................................................... 357
6.7.2 Configuring an MPLS TE Tunnel Interface............................................................................................................. 358
6.7.3 (Optional) Configuring Link Bandwidth................................................................................................................. 359
6.7.4 Configuring the Static CR-LSP.................................................................................................................................... 360
6.7.5 Verifying the Configuration of a Static MPLS TE Tunnel.................................................................................. 362
6.8 Configuring a Dynamic MPLS TE Tunnel................................................................................................................... 362
6.8.1 Enabling MPLS TE and RSVP-TE................................................................................................................................. 363
6.8.2 Configuring an MPLS TE Tunnel Interface............................................................................................................. 364
6.8.3 (Optional) Configuring Link Bandwidth................................................................................................................. 366
6.8.4 Advertising TE Link Information................................................................................................................................ 367
6.8.5 (Optional) Referencing the CR-LSP Attribute Template to Set Up a CR-LSP............................................. 368
6.8.6 (Optional) Configuring Tunnel Constraints........................................................................................................... 372
6.8.7 Configuring Path Calculation...................................................................................................................................... 374
6.8.8 Verifying the Configuration of a Dynamic MPLS TE Tunnel............................................................................ 375
6.9 Importing Traffic to an MPLS TE Tunnel.................................................................................................................... 377
6.9.1 Configuring Static Routes............................................................................................................................................ 377
6.9.2 Configuring a Tunnel Policy........................................................................................................................................ 378
6.9.3 Configuring Auto Routes.............................................................................................................................................. 378
6.9.4 Verifying the Configuration of Importing Traffic to an MPLS TE Tunnel.................................................... 380
6.10 Adjusting RSVP-TE Signaling Parameters................................................................................................................ 380
6.10.1 Configuring an RSVP Resource Reservation Style............................................................................................. 381
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6.10.2 Enabling Reservation Confirmation Mechanism............................................................................................... 382
6.10.3 Configuring RSVP Timers........................................................................................................................................... 382
6.10.4 Configuring RSVP-TE Refresh Mechanism............................................................................................................383
6.10.5 Configuring RSVP Hello Extension..........................................................................................................................384
6.10.6 Configuring the RSVP Message Format................................................................................................................ 385
6.10.7 Configuring RSVP Authentication........................................................................................................................... 387
6.10.8 Verifying the Configuration of Adjusting RSVP-TE Signaling Parameters.................................................390
6.11 Adjusting the Path of a CR-LSP................................................................................................................................... 391
6.11.1 Configuring Tie-Breaking of CSPF...........................................................................................................................391
6.11.2 Configuring Metrics for Path Calculation............................................................................................................. 392
6.11.3 Configuring CR-LSP Hop Limit................................................................................................................................. 394
6.11.4 Configuring Route Pinning........................................................................................................................................ 394
6.11.5 Configuring Administrative Group and Affinity Property............................................................................... 395
6.11.6 Configuring SRLG.......................................................................................................................................................... 396
6.11.7 Associating CR-LSP Establishment with the Overload Setting..................................................................... 398
6.11.8 Configuring Failed Link Timer.................................................................................................................................. 399
6.11.9 Configuring Flooding Threshold.............................................................................................................................. 400
6.11.10 Verifying the Configuration of Adjusting the Path of a CR-LSP................................................................ 401
6.12 Adjusting the Establishment of an MPLS TE Tunnel........................................................................................... 401
6.12.1 Configuring Loop Detection...................................................................................................................................... 402
6.12.2 Configuring Route Record and Label Record...................................................................................................... 402
6.12.3 Configuring Re-optimization for CR-LSP.............................................................................................................. 403
6.12.4 Configuring Tunnel Reestablishment Parameters............................................................................................. 404
6.12.5 Configuring the RSVP Signaling Delay-Trigger Function................................................................................ 405
6.12.6 Configuring the Tunnel Priority............................................................................................................................... 405
6.12.7 Verifying the Configuration of Adjusting the Establishment of an MPLS TE Tunnel............................406
6.13 Configuring CR-LSP Backup.......................................................................................................................................... 406
6.13.1 Creating a Backup CR-LSP......................................................................................................................................... 407
6.13.2 (Optional) Configuring Forcible Switchover........................................................................................................408
6.13.3 (Optional) Locking a Backup CR-LSP Attribute Template..............................................................................409
6.13.4 (Optional) Configuring Dynamic Bandwidth for Hot-Standby CR-LSPs................................................... 410
6.13.5 (Optional) Configuring a Best-Effort Path.......................................................................................................... 412
6.13.6 Verifying the CR-LSP Backup Configuration........................................................................................................413
6.14 Configuring Manual TE FRR......................................................................................................................................... 413
6.14.1 Enabling TE FRR............................................................................................................................................................ 414
6.14.2 Configuring a Bypass Tunnel.................................................................................................................................... 414
6.14.3 (Optional) Configuring a TE FRR Scanning Timer............................................................................................ 416
6.14.4 (Optional) Changing the PSB and RSB Timeout Multiplier........................................................................... 417
6.14.5 Verifying the Manual TE FRR Configuration....................................................................................................... 417
6.15 Configuring Auto TE FRR............................................................................................................................................... 418
6.15.1 Enabling Auto TE FRR................................................................................................................................................. 418
6.15.2 Enabling the TE FRR and Configuring the Auto Bypass Tunnel Attributes.............................................. 420
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6.15.3 (Optional) Configuring a TE FRR Scanning Timer............................................................................................ 420
6.15.4 (Optional) Changing the PSB and RSB Timeout Multiplier........................................................................... 421
6.15.5 (Optional) Configuring Auto Bypass Tunnel Re-Optimization..................................................................... 422
6.15.6 (Optional) Configuring Interworking with a Non-Huawei Device.............................................................. 423
6.15.7 Verifying the Auto TE FRR Configuration.............................................................................................................423
6.16 Configuring Association Between TE FRR and CR-LSP Backup........................................................................424
6.17 Configuring a Tunnel Protection Group................................................................................................................... 425
6.17.1 Creating a Tunnel Protection Group...................................................................................................................... 425
6.17.2 (Optional) Configuring the Protection Switching Trigger Mechanism...................................................... 426
6.17.3 Verifying the Configuration of a Tunnel Protection Group............................................................................ 428
6.18 Configuring Dynamic BFD for RSVP.......................................................................................................................... 428
6.18.1 Enabling BFD Globally................................................................................................................................................ 429
6.18.2 Enabling BFD for RSVP............................................................................................................................................... 429
6.18.3 (Optional) Adjusting BFD Parameters...................................................................................................................430
6.18.4 Verifying the Configuration of Dynamic BFD for RSVP...................................................................................431
6.19 Configuring Static BFD for CR-LSPs........................................................................................................................... 432
6.19.1 Enabling BFD Globally................................................................................................................................................ 432
6.19.2 Configuring BFD Parameters on the Ingress Node of the Tunnel............................................................... 433
6.19.3 Configuring BFD Parameters on the Egress Node of the Tunnel.................................................................435
6.19.4 Verifying the Configuration of Static BFD for CR-LSPs....................................................................................437
6.20 Configuring Dynamic BFD for CR-LSPs.................................................................................................................... 438
6.20.1 Enabling BFD Globally................................................................................................................................................ 439
6.20.2 Enabling the Capability of Dynamically Creating BFD Sessions on the Ingress..................................... 439
6.20.3 Enabling the Capability of Passively Creating BFD Sessions on the Egress..............................................440
6.20.4 (Optional) Adjusting BFD Parameters...................................................................................................................441
6.20.5 Verifying the Configuration of Dynamic BFD for CR-LSPs............................................................................. 442
6.21 Configuring Static BFD for TE Tunnels..................................................................................................................... 443
6.21.1 Enabling BFD Globally................................................................................................................................................ 443
6.21.2 Configuring BFD Parameters on the Ingress Node of the Tunnel............................................................... 444
6.21.3 Configuring BFD Parameters on the Egress Node of the Tunnel.................................................................446
6.21.4 Verifying the Configuration of Static BFD for TE Tunnels.............................................................................. 448
6.22 Configuring RSVP GR...................................................................................................................................................... 449
6.22.1 Enabling the RSVP Hello Extension Function..................................................................................................... 450
6.22.2 Enabling RSVP GR.........................................................................................................................................................450
6.22.3 (Optional) Enabling the RSVP GR Helper Function..........................................................................................451
6.22.4 (Optional) Configuring Hello Sessions Between RSVP GR Nodes...............................................................451
6.22.5 (Optional) Modifying Basic Time............................................................................................................................452
6.22.6 Verifying the RSVP GR Configuration.................................................................................................................... 453
6.23 Maintaining MPLS TE..................................................................................................................................................... 453
6.23.1 Verifying the Connectivity of the TE Tunnel........................................................................................................453
6.23.2 Verifying a TE Tunnel By Using NQA..................................................................................................................... 453
6.23.3 Enabling the MPLS TE Trap Function.....................................................................................................................454
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Contents
6.23.4 Configuring Conditions That Trigger CSPF Resource Threshold-Reaching Alarms................................459
6.23.5 Clearing the Operation Information...................................................................................................................... 460
6.23.6 Verifying Information About TE...............................................................................................................................461
6.23.7 Resetting the Tunnel Interface................................................................................................................................. 461
6.23.8 Resetting the RSVP Process....................................................................................................................................... 462
6.23.9 Deleting or Resetting the Bypass Tunnel............................................................................................................. 462
6.24 Configuration Examples for MPLS TE....................................................................................................................... 462
6.24.1 Example for Configuring a Static MPLS TE Tunnel........................................................................................... 462
6.24.2 Example for Configuring a Dynamic MPLS TE Tunnel.................................................................................... 467
6.24.3 Example for Setting Up CR-LSPs Using CR-LSP Attribute Templates......................................................... 473
6.24.4 Example for Configuring IGP Shortcut to Direct Traffic to an MPLS TE Tunnel.....................................485
6.24.5 Example for Configuring Forwarding Adjacency to Direct Traffic to an MPLS TE Tunnel.................. 491
6.24.6 Example for Setting Attributes for an MPLS TE Tunnel.................................................................................. 499
6.24.7 Example for Configuring Srefresh Based on Manual TE FRR........................................................................ 507
6.24.8 Example for Configuring RSVP Authentication.................................................................................................. 515
6.24.9 Example for Configuring RSVP Authentication Based on Manual TE FRR............................................... 520
6.24.10 Example for Configuring SRLG Based on Auto TE FRR................................................................................. 528
6.24.11 Example for Configuring SRLG Based on CR-LSP Hot Standby..................................................................539
6.24.12 Example for Configuring CR-LSP Hot Standby................................................................................................ 548
6.24.13 Example for Configuring Manual TE FRR.......................................................................................................... 557
6.24.14 Example for Configuring Auto TE FRR................................................................................................................ 568
6.24.15 Example for Configuring Association Between TE FRR and CR-LSP Backup......................................... 581
6.24.16 Example for Configuring an MPLS TE Tunnel Protection Group............................................................... 592
6.24.17 Example for Configuring Dynamic BFD for an MPLS TE Tunnel Protection Group............................ 599
6.24.18 Example for Configuring Static BFD for CR-LSPs............................................................................................ 605
6.24.19 Example for Configuring Dynamic BFD for CR-LSPs......................................................................................611
6.24.20 Example for Configuring RSVP GR....................................................................................................................... 617
7 Seamless MPLS Configuration......................................................................................... 624
7.1 Overview of Seamless MPLS.......................................................................................................................................... 624
7.2 Understanding Seamless MPLS..................................................................................................................................... 625
7.3 Application of Seamless MPLS in VPN........................................................................................................................ 632
7.4 Licensing Requirements and Limitations for Seamless MPLS............................................................................. 632
7.5 Configuring Intra-AS Seamless MPLS.......................................................................................................................... 633
7.5.1 Configuring AGG and Core ABR as RRs...................................................................................................................634
7.5.2 Enabling BGP Peers to Exchange Labeled IPv4 Routes......................................................................................635
7.5.3 Configuring a BGP LSP.................................................................................................................................................. 635
7.5.4 (Optional) Configure BGP Auto FRR........................................................................................................................ 637
7.5.5 Verifying the Intra-AS Seamless MPLS Configuration........................................................................................638
7.6 Configuring Inter-AS Seamless MPLS.......................................................................................................................... 638
7.6.1 Configuring AGG as the RR......................................................................................................................................... 639
7.6.2 Enabling BGP Peers to Exchange Labeled IPv4 Routes......................................................................................639
7.6.3 Configuring a BGP LSP.................................................................................................................................................. 641
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7.6.4 (Optional) Configure BGP Auto FRR........................................................................................................................ 643
7.6.5 Verifying the Inter-AS Seamless MPLS Configuration........................................................................................ 644
7.7 Configuring Dynamic BFD to Monitor a BGP Tunnel............................................................................................ 644
7.7.1 Enabling an MPLS Device to Dynamically Establish a BGP BFD Session.................................................... 645
7.7.2 Configuring a Policy for Dynamically Establishing a BGP BFD Session....................................................... 646
7.7.3 (Optional) Adjusting BGP BFD Parameters........................................................................................................... 647
7.7.4 Verifying the Configuration of Dynamic BFD to Monitor a BGP Tunnel..................................................... 648
7.8 Verifying Connectivity and Reachability of Seamless MPLS Networks............................................................648
7.9 Configuration Examples for Seamless MPLS............................................................................................................ 648
7.9.1 Example for Configuring Intra-AS Seamless MPLS............................................................................................. 648
7.9.2 Example for Configuring Inter-AS Seamless MPLS..............................................................................................658
7.9.3 Example for Configuring Intra-AS Seamless MPLS to Transmit VLL Services............................................ 667
7.9.4 Example for Configuring Dynamic BFD to Monitor a BGP Tunnel................................................................ 678
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1 MPLS Features Supported in This Version
MPLS Features Supported in This Version
The configuration modes supported by different models are as follows:
●
S1720GW (without license), S1720GWR (without license) and S1720X
(without license): Web Configuration (For the web configuration, see
S1720GW, S1720GWR, S1720X, S1720GW-E, S1720GWR-E, and S1720X-E
V200R011C10 Web System Guide.)
●
S1720GW (license loaded), S1720GWR (license loaded), S1720X (license
loaded), S1720GW-E (license loaded), S1720GWR-E (license loaded) and
S1720X-E (license loaded): Web Configuration (For the web configuration, see
S1720GW, S1720GWR, S1720X, S1720GW-E, S1720GWR-E, and S1720X-E
V200R011C10 Web System Guide) and CLI. CLI configuration supports the
following features.
●
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Other models: Web Configuration (For the web configuration, see S1720GFR,
S2700, S5700, and S6720 V200R011C10 Web System Guide) and CLI. CLI
configuration supports the following features.
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Featu
re
S17
20G
FR
S17
20G
W
1 MPLS Features Supported in This Version
S27
20EI
S5700
LI
S5720
LI
S5720
SI
S5720
EI
S672
0LI
S672
0SI
S672
0EI
S27
50EI
S5700
S-LI
S5720
S-LI
S5720
S-SI
S5720
HI
S672
0S-LI
S672
0S-SI
S672
0S-EI
S5710
-X-LI
S17
20G
WR
S5730
SI
S5730
S-EI
S17
20X
S17
20G
W-E
S17
20G
WRE
S17
20XE
Static
LSP
Not
supp
orte
d
Not
supp
orte
d
Not
suppo
rted
Not
suppo
rted
Not
suppo
rted
Suppo
rted
Not
supp
orted
Not
supp
orted
Supp
orted
MPLS
LDP
Not
supp
orte
d
Not
supp
orte
d
Not
suppo
rted
Not
suppo
rted
Not
suppo
rted
Suppo
rted
Not
supp
orted
Not
supp
orted
Supp
orted
MPLS
QoS
Not
supp
orte
d
Not
supp
orte
d
Not
suppo
rted
Not
suppo
rted
Not
suppo
rted
Suppo
rted
Not
supp
orted
Not
supp
orted
Supp
orted
MPLS
TE
Not
supp
orte
d
Not
supp
orte
d
Not
suppo
rted
Not
suppo
rted
Not
suppo
rted
Suppo
rted
Not
supp
orted
Not
supp
orted
Supp
orted
Seam
less
MPLS
Not
supp
orte
d
Not
supp
orte
d
Not
suppo
rted
Not
suppo
rted
Not
suppo
rted
Suppo
rted
Not
supp
orted
Not
supp
orted
Supp
orted
Issue 10 (2019-12-30)
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Configuration Guide - MPLS
1 MPLS Features Supported in This Version
On the S5720EI switch, if hardware support for MPLS is displayed as NO in the output of
the display device capability command, the switch does not support MPLS.
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2 MPLS Basics
2
MPLS Basics
About This Chapter
This chapter describes how to configure Multiprotocol Label Switching (MPLS)
basics.
2.1 Overview of MPLS
2.2 Understanding MPLS
2.3 Application Scenarios for MPLS
2.1 Overview of MPLS
Definition
The Multiprotocol Label Switching (MPLS) protocol is used on Internet Protocol
(IP) backbone networks. MPLS uses connection-oriented label switching on
connectionless IP networks. By combining Layer 3 routing technologies and Layer
2 switching technologies, MPLS leverages the flexibility of IP routing and the
simplicity of Layer 2 switching.
MPLS is based on Internet Protocol version 4 (IPv4). The core MPLS technology
can be extended to multiple network protocols, such as Internet Protocol version 6
(IPv6), Internet Packet Exchange (IPX), and Connectionless Network Protocol
(CLNP). "Multiprotocol" in MPLS means that multiple network protocols are
supported.
MPLS is used for tunneling but not a service or an application. MPLS supports
multiple protocols and services. Moreover, it ensures security of data transmission.
Purpose
IP-based routing serves well on the Internet in the mid 90s, but IP technology can
be inefficient at forwarding packets because software must search for routes using
the longest match algorithm. As a result, the forwarding capability of IP
technology can act as a bottleneck.
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In contrast, Asynchronous transfer mode (ATM) technology uses labels of fixed
length and maintains a label table that is much smaller than a routing table.
Compared to IP, ATM is more efficient at forwarding packets. ATM is a complex
protocol, however, with high deployment costs, that hinder its widespread use.
Because traditional IP technology is simple and costs little to deploy, a
combination of IP and ATM capabilities would be ideal. This has sparked the
emergence of MPLS technology.
MPLS was created to increase forwarding rates. Unlike IP routing and forwarding,
MPLS analyzes a packet header only on the edge of the network and not at each
hop. MPLS therefore reduces packet processing time.
The use of hardware-based functions based on application-specific integrated
circuits (ASICs) has made IP routing far more efficient, so MPLS is no longer
needed for its high-speed forwarding advantages. However, MPLS does support
multi-layer labels, and its forwarding plane is connection-oriented. For these
reasons, MPLS is widely used for virtual private network (VPN), traffic engineering
(TE), and quality of service (QoS).
2.2 Understanding MPLS
2.2.1 Basic MPLS Architecture
MPLS Network Structure
Figure 2-1 shows a typical MPLS network structure. Packets are forwarded on an
MPLS network based on labels. In Figure 2-1, network devices that swap MPLS
labels and forward packets are label switching routers (LSRs), which form an
MPLS domain. LSRs that reside at the edge of the MPLS domain and connect to
other networks are called label edge routers (LERs), and LSRs within the MPLS
domain are core LSRs.
Figure 2-1 MPLS network structure
LER
MPLS Domain
Transit
Ingress
LER
Egress
LER
Core LSR
IP Network
IP Network
LER
LER
LSP
Data flow
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2 MPLS Basics
When IP packets reach an MPLS network, the ingress LER analyzes the packets
and then adds appropriate labels to them. All LSRs on the MPLS network forward
packets based on labels. When IP packets leave the MPLS network, the egress LER
pops the labels.
A path along which IP packets are transmitted on an MPLS network is called a
label switched path (LSP). An LSP is a unidirectional path in the same direction
data packets traverse.
As shown in Figure 2-1, the LER at the starting point of an LSP is the ingress
node, and the LER at the end of the LSP is the egress node. The LSRs between the
ingress node and egress node along the LSP are transit nodes. An LSP may have
zero, one, or several transit nodes and only one ingress node and one egress node.
On an LSP, MPLS packets are sent from the ingress to the egress. In this
transmission direction, the ingress node is the upstream node of the transit nodes,
and the transit nodes are the downstream nodes of the ingress node. Similarly,
transit nodes are the upstream nodes of the egress node, and the egress node is
the downstream node of the transit nodes.
MPLS Architecture
Figure 2-2 shows the MPLS architecture, which consists of a control plane and a
forwarding plane.
Figure 2-2 MPLS architecture
IP routing protocol
Control plane
Routing Information
Base (RIB)
Label Distribution
Protocol (LDP)
Forwarding
Information Base
(FIB)
Label Forwarding
Information Base
(LFIB)
Label Information
Base (LIB)
Forwarding plane
The MPLS architecture has the following parts:
●
Issue 10 (2019-12-30)
Control plane: generates and maintains routing and label information
–
Routing information base (RIB): is generated by IP routing protocols and
used to select routes.
–
Label distribution protocol (LDP): allocates labels, creates a label
information base (LIB), and establishes and tears down LSPs.
–
Label information base (LIB): is generated by LDP and used to manage
labels.
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●
2 MPLS Basics
Forwarding plane (data plane): forwards IP packets and MPLS packets
–
Forwarding information base (FIB): is generated based on routing
information obtained from the RIB and used to forward common IP
packets.
–
Label forwarding information base (LFIB): is created by LDP on an LSR
and used to forward MPLS packets.
2.2.2 MPLS Label
Forwarding Equivalence Class
A forwarding equivalence class (FEC) is a collection of packets with the same
characteristics. Packets of the same FEC are forwarded in the same way on an
MPLS network.
FECs can be identified by the source address, destination address, source port,
destination port, and VPN. For example, in IP forwarding, packets matching the
same route based on the longest match algorithm belong to an FEC.
Label
A label is a short, fixed-length (4 bytes) identifier that is only locally significant. A
label identifies an FEC to which a packet belongs. In some cases, such as load
balancing, a FEC can be mapped to multiple incoming labels. Each label, however,
represents only one FEC on a device.
Compared with an IP packet, an MPLS packet has the additional 4-byte MPLS
label. The MPLS label is between the link layer header and the network layer
header, and allows use of any link layer protocol. Figure 2-3 shows position of an
MPLS label and fields in the MPLS label.
Figure 2-3 MPLS label encapsulation format
Link layer header
MPLS Label
Layer 3 header
19
0
Label
Layer 3 payload
22 23
Exp S
31
TTL
An MPLS label contains the following fields:
●
Label: 20-bit label value.
●
Exp: 3-bit, used as an extension value. Generally, this field is used as the class
of service (CoS) field. When congestion occurs, devices prioritize packets that
have a larger value in this field.
●
S: 1-bit value indicating the bottom of a label stack. MPLS supports nesting of
multiple labels. When the S field is 1, the label is at the bottom of the label
stack.
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●
2 MPLS Basics
TTL: time to live. This 8-bit field is the same as the TTL field in IP packets.
A label stack is an arrangement of labels. In Figure 2-4, the label next to the
Layer 2 header is the top of the label stack (outer MPLS label), and the label next
to the Layer 3 header is the bottom of the label stack (inner MPLS label). An
MPLS label stack can contain an unlimited number of labels. Currently, MPLS label
stacks can be applied to MPLS VPN and Traffic Engineering Fast ReRoute (TE
FRR).
Figure 2-4 Label stack
Label Stack
Link layer header Outer MPLS label Inner MPLS label
Layer3 header
Layer3 payload
The label stack organizes labels according to the rule of Last-In, First-Out. The
labels are processed from the top of the stack.
Label Space
The label space is the value range of the label, and the space is organized in the
following ranges:
●
0 to 15: special labels. For details about special labels, see Table 2-1.
●
16 to 1023: label space shared by static LSPs and static constraint-based
routed LSPs (CR-LSPs).
●
1024 or above: label space for dynamic signaling protocols, such as Label
Distribution Protocol (LDP), Resource Reservation Protocol-Traffic Engineering
(RSVP-TE), and MultiProtocol Border Gateway Protocol (MP-BGP).
Table 2-1 Special labels
Label Value
Label
Description
0
IPv4 Explicit
NULL Label
The label must be popped out (removed), and the
packets must be forwarded based on IPv4. If the
egress node allocates a label with the value of 0
to the penultimate hop LSR, the penultimate hop
LSR pushes label 0 to the top of the label stack
and forwards the packet to the egress node.
When the egress node detects that the label of
the packet is 0, the egress node pops the label
out.
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2 MPLS Basics
Label Value
Label
Description
1
Router Alert
Label
A label that is only valid when it is not at the
bottom of a label stack. The label is similar to the
Router Alert Option field in IP packets. After
receiving such a label, the node sends it to a local
software module for further processing. Packet
forwarding is determined by the next-layer label.
If the packet needs to be forwarded continuously,
the node pushes the Router Alert Label to the top
of the label stack again.
2
IPv6 Explicit
NULL Label
The label must be popped out, and the packets
must be forwarded based on IPv6. If the egress
node allocates a label with the value of 2 to the
LSR at the penultimate hop, the LSR pushes label
2 to the top of the label stack and forwards the
packet to the egress node. When the egress node
recognizes that the value of the label carried in
the packet is 2, the egress node immediately pops
it out.
3
Implicit
NULL Label
When the label with the value of 3 is swapped on
an LSR at the penultimate hop, the LSR pops the
label out and forwards the packet to the egress
node. Upon receiving the packet, the egress node
forwards the packet in IP forwarding mode or
according to the next layer label.
4 to 13
Reserved
None.
14
OAM Router
Alert Label
A label for operation, administration and
maintenance (OAM) packets over an MPLS
network. MPLS OAM sends OAM packets to
monitor LSPs and report faults. OAM packets are
transparent on transit nodes and the penultimate
LSR.
15
Reserved
None.
2.2.3 LSP Setup
Before forwarding packets, MPLS must allocate labels to packets and establish an
LSP. LSPs can be either static or dynamic.
Establishing Static LSPs
You can manually allocate labels to set up static LSPs. A static LSP is valid for only
the local node, and nodes on the LSP are unaware of the entire LSP.
A static LSP is set up without any label distribution protocols or exchange of
control packets. Static LSPs have low costs and are recommended for small-scale
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networks with simple and stable topologies. Static LSPs cannot adapt to network
topology changes and must be configured by an administrator.
Establishing Dynamic LSPs
Label Distribution Protocols for Dynamic LSPs
Dynamic LSPs are established using label distribution protocols. As the control
protocol or signaling protocol for MPLS, a label distribution protocol defines FECs,
distributes labels, and establishes and maintains LSPs.
MPLS can use the following protocols for label distribution:
●
LDP
The Label Distribution Protocol (LDP) is designed for distributing labels. It sets
up an LSP hop by hop according to Interior Gateway Protocol (IGP) and
Border Gateway Protocol (BGP) routing information.
For details about LDP implementation, see Understanding MPLS LDP in the 4
MPLS LDP Configuration.
●
RSVP-TE
Resource Reservation Protocol Traffic Engineering (RSVP-TE) is an extension
of RSVP and is used to set up a constraint-based routed LSP (CR-LSP). In
contrast to LDP LSPs, RSVP-TE tunnels are characterized by bandwidth
reservation requests, bandwidth constraints, link "colors" (designating
administrative groups), and explicit paths.
For details about RSVP-TE implementation, see Understanding MPLS TE in the
6 MPLS TE Configuration.
●
MP-BGP
MP-BGP is an extension to BGP and allocates labels to MPLS VPN routes and
inter-AS VPN routes.
For details about MP-BGP implementation, see BGP Configuration in the
S1720, S2700, S5700, and S6720 V200R011C10 Configuration Guide - IP
Unicast Routing.
Procedure for Establishing Dynamic LSPs
MPLS labels are distributed from downstream LSRs to upstream LSRs. As shown in
Figure 2-5, a downstream LSR identifies FECs based on the IP routing table,
allocates a label to each FEC, and records the mapping between labels and FECs.
The downstream LSR then encapsulates the mapping into a message and sends
the message to the upstream LSR. As this process proceeds on all the LSRs, the
LSRs create a label forwarding table and establish an LSP.
Figure 2-5 Establishing a dynamic LSP
Upstream
To 4.4.4.2/32
Label=Z
Ingress
To 4.4.4.2/32
Label=Y
Transit
To 4.4.4.2/32
Downstream
Label=3
Transit
Egress
4.4.4.2/32
LSP
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2.2.4 MPLS Forwarding
MPLS Forwarding Process
Basic Concepts
Label operations involved in MPLS packet forwarding include push, swap, and pop:
●
Push: When an IP packet enters an MPLS domain, the ingress node adds a
new label to the packet between the Layer 2 header and the IP header.
Alternatively, an LSR adds a new label to the top of the label stack.
●
Swap: When a packet is transferred within the MPLS domain, a local node
swaps the label at the top of the label stack in the MPLS packet for the label
allocated by the next hop according to the label forwarding table.
●
Pop: When a packet leaves the MPLS domain, the label is popped out of
(removed from) the MPLS packet.
A label is invalid at the last hop of an MPLS domain. The penultimate hop
popping (PHP) feature applies. On the penultimate node, the label is popped
out of the packet to reduce the size of the packet that is forwarded to the last
hop. Then, the last hop directly forwards the IP packet or forwards the packet
by using the second label.
By default, PHP is configured on the egress node. The egress node supporting
PHP allocates the label with the value of 3 to the penultimate hop.
Basic Forwarding Process
LSPs that support PHP are used in the following example to describe how MPLS
packets are forwarded.
Figure 2-6 Basic MPLS forwarding process
FEC
4.4.4.2/32
In/Out Label In/Out IF
NULL/Z
IF1/IF2
FEC
4.4.4.2/32
In/Out Label In/Out IF
Z/Y
IF1/IF2
FEC
4.4.4.2/32
In/Out Label In/Out IF
Y/3
IF1/IF2
Push
Z IP:4.4.4.2
Swap Y IP:4.4.4.2
Pop IP:4.4.4.2
IP
:4
.
2
4.
4.
.
:4
IP
4.
4.
2
PHP
IF1
IF2
Ingress
IF1
IF2
Transit
IF1
IF2
Transit
IF1
IF2
Egress
4.4.4.2/32
Data flow
LSP
As shown in Figure 2-6, the LSRs have distributed MPLS labels and set up an LSP
with the destination address of 4.4.4.2/32. MPLS packets are forwarded as follows:
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1.
The ingress node receives an IP packet destined for 4.4.4.2. Then, the ingress
node adds Label Z to the packet and forwards it.
2.
When the downstream transit node receives the labeled packet, the node
replaces Label Z by Label Y.
3.
When the transit node at the penultimate hop receives the packet with Label
Y, the node pops out Label Y because the label value is 3. The transit node
then forwards the packet to the egress node as an IP packet.
4.
The egress node receives the IP packet and forwards it to 4.4.4.2/32.
Detailed MPLS Packet Forwarding Process
Basic Concepts
The following entities are used in MPLS packet forwarding:
●
Tunnel ID
Each tunnel is assigned a unique ID to ensure that upper layer applications
(such as VPN and route management) on a tunnel use the same interface.
The tunnel ID is 32 bits long and is valid only on the local end.
●
NHLFE
A next hop label forwarding entry (NHLFE) is used to guide MPLS packet
forwarding.
An NHLFE specifies the tunnel ID, outbound interface, next hop, outgoing
label, and label operation.
FEC-to-NHLFE (FTN) maps each FEC to a group of NHLFEs. An FTN can be
obtained by searching for tunnel IDs that are not 0x0 in a FIB. The FTN is
available on the ingress only.
●
ILM
The incoming label map (ILM) maps each incoming label to a group of
NHLFEs.
The ILM specifies the tunnel ID, incoming label, inbound interface, and label
operation.
The ILM on a transit node identifies bindings between labels and NHLFEs.
Similar a FIB that provides forwarding information based on destination IP
addresses, the ILM provides forwarding information based on labels.
Detailed Forwarding Process
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Figure 2-7 Detailed MPLS packet forwarding process
NHLFE
OUT IF Tunnel ID OPER NEXTHOP Out Label
IF2
0x11
PUSH
1.1.1.2
Z
OUT IF Tunnel ID OPER NEXTHOP Out Label
IF2
0x15
SWAP
2.2.2.2
Y
OUT IF Tunnel ID OPER NEXTHOP Out Label
IF2
DEST
Tunnel ID
ILM
In Label
In IF
4.4.4.2/32
0x11
Z
IF1
0x15
Swap Y IP:4.4.4.2
Y
0x22
PHP
IP:4.4.4.2
4.
:4
.
IF1
2
4.
4.
IP
3
Tunnel ID
IF1
Pop
3.3.3.2
.
:4
4.
Push Z IP:4.4.4.2
Tunnel ID In Label In IF
POP
IP
2
FIB
0x22
IF2
1.1.1.1/24
Ingress
IF1
IF2
1.1.1.2/24 2.2.2.1/24
Transit
IF1
IF2
2.2.2.2/24 3.3.3.1/24
Transit
IF1
IF2
3.3.3.2/24
Egress 4.4.4.2/32
Figure 2-7 shows the detailed MPLS packet forwarding process.
When an IP packet enters an MPLS domain, the ingress node searches the FIB to
check whether the tunnel ID matching the destination IP address is 0x0.
●
If the tunnel ID is 0x0, the packet is forwarded along the IP link.
●
If the tunnel ID is not 0x0, the packet is forwarded along an LSP.
During MPLS forwarding, LSRs find the matching FIB entries, ILM entries, and
NHLFEs for MPLS packets based on tunnel IDs.
●
The ingress node processes MPLS packets as follows:
a.
Searches the FIB to find the tunnel ID matching the destination IP
address.
b.
Finds the NHLFE matching the tunnel ID in the FIB and associates the FIB
entry with the NHLFE entry.
c.
Checks the NHLFE to obtain the outbound interface, next hop, outgoing
label, and label operation.
d.
Pushes the label into IP packets, processes the EXP field according to QoS
policy, and processes the TTL field, and then sends the encapsulated
MPLS packets to the next hop.
For details on how the ingress node processes the EXP field and TTL field, see
Understanding MPLS QoS in the 5 MPLS QoS Configuration and Processing
MPLS TTL.
●
A transit node processes MPLS packets as follows:
a.
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●
2 MPLS Basics
b.
Finds the NHLFE matching the Tunnel ID in the ILM.
c.
Checks the NHLFE to obtain the outbound interface, next hop, outgoing
label, and label operation.
d.
Processes the MPLS packets according to the label value:
n
If the label value is greater than or equal to 16, the transit node
replaces the label with a new label replaces and processes the EXP
field and TTL field. After that, the transit node forwards the MPLS
packet with the new label to the next hop.
n
If the label value is 3, the transit node pops out the label and
processes the EXP field and TTL field. After that, the transit node
forwards the packets through an IP route or based on the next layer
label.
The egress node forwards MPLS packets based on the ILM and forwards IP
packets based on the routing table
–
When the egress node receives IP packets, it checks the FIB and performs
IP forwarding.
–
When the egress node receives MPLS packets, it checks the ILM for the
label operation and processes the EXP field and TTL field.
n
When the S flag in the label is 1, the label is at the bottom of the
label stack, and the packet is directly forwarded through an IP route.
n
When the S field in the label is 0, a next-layer label exists, and the
packet is forwarded based on the next layer label.
MPLS TTL Processing
This section describes how MPLS processes the TTL and responds to TTL timeout.
MPLS TTL Processing Modes
The TTL field in an MPLS label is 8 bits long. The TTL field is the same as that in
an IP packet header. MPLS processes the TTL to prevent loops and implement
traceroute.
RFC 3443 defines two modes in which MPLS can process the TTL in MPLS packets:
Uniform and Pipe modes. By default, MPLS processes the TTL in Uniform mode.
The two modes work as follows:
●
Uniform mode
When IP packets enter an MPLS network, the ingress node decreases the IP
TTL by one and copies this new value to the MPLS TTL field. The TTL field in
MPLS packets is processed in standard mode. The egress node decreases the
MPLS TTL by one and maps this new value to the IP TTL field. Figure 2-8
shows how the TTL field is processed on the transmission path.
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Figure 2-8 TTL processing in Uniform mode for incoming traffic
PE
CE
MPLS
TTL 254
IP TTL
254
IP TTL
255
●
IP/MPLS
backbone network
P
PE
MPLS
TTL 253
IP TTL
254
CE
IP TTL
252
Pipe mode
As shown in Figure 2-9, the ingress node decreases the IP TTL by one and the
MPLS TTL remains constant. The TTL field in MPLS packets is processed in
standard mode. The egress node decreases the IP TTL by one. In Pipe mode,
the IP TTL only decreases by one on the ingress node and one on the egress
node when packets travel across an MPLS network.
Figure 2-9 TTL processing in Pipe mode for incoming traffic
PE
CE
IP TTL
255
Outer MPLS
TTL 100
Inner MPLS
TTL 100
IP TTL
254
IP/MPLS
backbone network
P
PE
Outer MPLS
TTL 99
Inner MPLS
TTL 100
IP TTL
254
CE
IP TTL
253
In MPLS VPN applications, the MPLS backbone network needs to be shielded to
ensure network security. The Pipe mode is recommended for private network
packets.
ICMP Response Packet
On an MPLS network, when an LSR receives an MPLS packet with the TTL value of
1, the LSR generates an Internet Control Message Protocol (ICMP) response
packet.
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The LSR returns the ICMP response packet to the sender in the following ways:
●
If the LSR has a reachable route to the sender, the LSR directly sends the
ICMP response packet to the sender through the IP route.
●
If the LSR has no reachable route to the sender, the LSR forwards the ICMP
response packet along the LSP. The egress node forwards the ICMP response
packet to the sender.
In most cases, the received MPLS packet contains only one label and the LSR
responds to the sender with the ICMP response packet using the first method. If
the MPLS packet contains multiple labels, the LSR uses the second method.
The MPLS VPN packets may contain only one label when they arrive at an
autonomous system boundary router (ASBR) on the MPLS VPN. These devices
have no IP routes to the sender, so they use the second method to reply to the
ICMP response packets.
2.2.5 LSP Connectivity Check
Introduction to LSP Connectivity Check
On an MPLS network, the control panel used for setting up an LSP cannot detect
the failure in data forwarding of the LSP. This makes network maintenance
difficult. The MPLS ping and tracert mechanisms detect LSP errors and locate
faulty nodes.
MPLS ping is used to check network connectivity. MPLS tracert is used to check
the network connectivity, and to locate network faults. Similar to IP ping and
tracert, MPLS ping and tracert use MPLS echo request packets and MPLS echo
reply packets to check LSP availability. MPLS echo request packets and echo reply
packets are both encapsulated into User Datagram Protocol (UDP) packets. The
UDP port number of the MPLS echo request packet is 3503, which can be
identified only by MPLS-enabled devices.
An MPLS echo request packet carries FEC information to be detected, and is sent
along the same LSP as other packets with the same FEC. In this manner, the
connectivity of the LSP is checked. MPLS echo request packets are forwarded to
the destination end using MPLS, while MPLS echo reply packets are forwarded to
the source end using IP. Routers set the destination address in the IP header of the
MPLS echo request packets to 127.0.0.1/8 (local loopback address) and the TTL
value is 1. In this way, MPLS echo request packets are not forwarded using IP
forwarding when the LSP fails so that the failure of the LPS can be detected.
MPLS Ping
Figure 2-10 MPLS network
Loopback0
5.5.5.5/32
Loopback0
4.4.4.4/32
LSP
LSR_1
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LSR_2
LSR_3
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As shown in Figure 2-10, LSR_1 establishes an LSP to LSR_4. LSR_1 performs MPLS
ping on the LSP by performing the following steps:
1.
LSR_1 checks whether the LSP exists. (On a TE tunnel, the router checks
whether the tunnel interface exists and the CR-LSP has been established.) If
the LSP does not exist, an error message is displayed and the MPLS ping
stops. If the LSP exists, LSR_1 performs the following operations.
2.
LSR_1 creates an MPLS echo request packet and adds 4.4.4.4 to the
destination FEC in the packet. In the IP header of the MPLS echo request
packet, the destination address is 127.0.0.1/8 and the TTL value is 1. LSR_1
searches for the corresponding LSP, adds the LSP label to the MPLS echo
request packet, and sends the packet to LSR_2.
3.
Transit nodes LSR_2 and LSR_3 forward the MPLS echo request packet based
on MPLS. If MPLS forwarding on a transit node fails, the transit node returns
an MPLS echo reply packet carrying the error code to LSR_1.
4.
If no fault exists along the MPLS forwarding path, the MPLS echo request
packet reaches the LSP egress node LSR_4. LSR_4 returns a correct MPLS echo
reply packet after verifying that the destination IP address 4.4.4.4 is the
loopback interface address. MPLS ping is complete.
MPLS Tracert
As shown in Figure 2-10, LSR_1 performs MPLS tracert on LSR_4 (4.4.4.4/32) by
performing the following steps:
1.
LSR_1 checks whether an LSP exists to LSR_4. (On a TE tunnel, the router
checks whether the tunnel interface exists and the CR-LSP has been
established.) If the LSP does not exist, an error message is displayed and the
tracert stops. If the LSP exists, LSR_1 performs the following operations.
2.
LSR_1 creates an MPLS echo request packet and adds 4.4.4.4 to the
destination FEC in the packet. In the IP header of the MPLS echo request
packet, the destination address is 127.0.0.1/8. Then LSR_1 adds the LSP label
to the packet, sets the MPLS TTL value to 1, and sends the packet to LSR_2.
The MPLS echo request packet contains a downstream mapping type-lengthvalue (TLV) that carries downstream information about the LSP at the current
node, such as next-hop address and outgoing label.
3.
Upon receiving the MPLS echo request packet, LSR_2 decreases the MPLS TTL
by one and finds that TTL times out. LSR_2 then checks whether the LSP
exists and the next-hop address and whether the outgoing label of the
downstream mapping TLV in the packet is correct. If so, LSR_2 returns a
correct MPLS echo reply packet that carries the downstream mapping TLV of
LSR_2. If not, LSR_2 returns an incorrect MPLS echo reply packet.
4.
After receiving the correct MPLS echo reply packet, LSR_1 resends the MPLS
echo request packet that is encapsulated in the same way as step 2 and sets
the MPLS TTL value to 2. The downstream mapping TLV of this MPLS echo
request packet is replicated from the MPLS echo reply packet. LSR_2 performs
common MPLS forwarding on this MPLS echo request packet. If TTL times out
when LSR_3 receives the MPLS echo request packet, LSR_3 processes the
MPLS echo request packet and returns an MPLS echo reply packet in the same
way as step 3.
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After receiving a correct MPLS echo reply packet, LSR_1 repeats step 4, sets
the MPLS TTL value to 3, replicates the downstream mapping TLV in the
MPLS echo reply packet, and sends the MPLS echo request packet. LSR_2 and
LSR_3 perform common MPLS forwarding on this MPLS echo request packet.
Upon receiving the MPLS echo request packet, LSR_4 repeats step 3 and
verifies that the destination IP address 4.4.4.4 is the loopback interface
address. LSR_4 returns an MPLS echo reply packet that does not carry the
downstream mapping TLV. MPLS tracert is complete.
When routers return the MPLS echo reply packet that carries the downstream
mapping TLV, LSR_1 obtains information about each node along the LSP.
2.3 Application Scenarios for MPLS
2.3.1 MPLS VPN
Traditional VPNs transmit private network data over the public network using
tunneling protocols, such as the Generic Routing Encapsulation (GRE), Layer 2
Tunneling Protocol (L2TP), and Point to Point Tunneling Protocol (PPTP). MPLS
LSPs are set up by swapping labels, and data packets are not encapsulated or
encrypted. Therefore, MPLS is an appropriate technology for VPN implementation.
MPLS VPN can build a private network with security similar to a Frame Relay (FR)
network. On MPLS VPN networks, customer devices do not need to set up tunnels
such as GRE and L2TP tunnels, so the network delay is minimized.
As shown in Figure 2-11, the MPLS VPN connects private network branches
through LSPs to form a unified network. The MPLS VPN also controls the
interconnection between VPNs. Figure 2-11 shows the devices on an MPLS VPN
network.
●
A customer edge (CE) is deployed on the edge of a customer network. It can
be a router, a switch, or a host.
●
A provider edge (PE) is deployed on the edge of an IP/MPLS backbone
network.
●
A provider (P) device on an IP/MPLS backbone network is not directly
connected to CEs. The provider device only needs to provide basic MPLS
forwarding capabilities and does not maintain VPN information.
Figure 2-11 MPLS VPN
VPN 1
Site
CE
IP/MPLS
backbone network
P
PE
P
VPN 2
Site
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P
P
CE
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PE
CE
VPN 2
Site
CE
VPN 1
Site
PE
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An MPLS VPN has the following characteristics:
●
PEs manage VPN users, set up LSPs between PEs, and advertise routing
information between users in a VPN.
●
PEs use MP-BGP to advertise VPN routing information.
●
The MPLS-based VPN supports IP address multiplexing between sites as well
as the interconnection of different VPNs.
2.3.2 MPLS TE
On traditional IP networks, routers select the shortest path as the route regardless
of other factors such as bandwidth. Traffic on a path is not switched to other
paths even if the path is congested. As a result, the shortest path first rule can
cause severe problems on networks.
Traffic engineering (TE) monitors network traffic and the load of network
components and then adjusts parameters such as traffic management, routing,
and resource restraint parameters in real time. These adjustments help prevent
network congestion caused by unbalanced traffic distribution.
TE can be implemented on a large-scale backbone network using a simple,
scalable solution. MPLS, an overlay model, allows a virtual topology to be
established over a physical topology and maps traffic to the virtual topology.
MPLS can be integrated with TE to implement MPLS TE.
As shown in Figure 2-12, two paths are set up between LSR_1 and LSR_7: LSR_1 > LSR_2 -> LSR_3 -> LSR_6 -> LSR_7 and LSR_1 -> LSR_2 -> LSR_4 -> LSR_5 ->
LSR_6 -> LSR_7. Bandwidth of the first path is 30 Mbit/s, and bandwidth of the
second path is 80 Mbit/s. TE allocates traffic based on bandwidth, preventing link
congestion. For example, 30 Mbit/s and 50 Mbit/s services are running between
LSR_1 and LSR_7. TE distributes the 30 Mbit/s traffic to the 30 Mbit/s path and the
50 Mbit/s traffic to the 80 Mbit/s path.
Figure 2-12 MPLS TE
LSR_3
LSR_1
LSR_2
LSR_6
LSR_7
30 Mbit/s bandwidth
LSR_4
LSR_5
80 Mbit/s bandwidth
30 Mbit/s traffic
50 Mbit/s traffic
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MPLS TE can reserve resources by setting up LSPs along a specified path to
prevent network congestion and balance network traffic. MPLS TE has the
following advantages:
●
MPLS TE can reserve resources to ensure the quality of services during the
establishment of LSPs.
●
The behavior of an LSP can be easily controlled based on the attributes of the
LSP such as priority and bandwidth.
●
LSP establishment consumes few resources and does not affect other network
services.
●
Backup path and fast reroute (FRR) protect network communication upon a
failure of a link or a node.
These advantages make MPLS TE the optimal TE solution. MPLS TE allows service
providers (SPs) to fully leverage existing network resources to provide diverse
services, optimize network resources, and efficiently manage the network.
2.3.3 MPLS 6PE
IPv6 Provider Edge (6PE) is an IPv4-to-IPv6 transition technology. This technology
allows ISPs to provide access services for scattered IPv6 networks over existing
IPv4 backbone networks. In this way, CEs on IPv6 islands can communicate with
each other through IPv4 PEs.
On an MPLS 6PE network shown in Figure 2-13:
●
6PE routers exchange IPv6 routing information with CEs using IPv6 routing
protocols.
●
6PE routers exchange IPv6 routing information with each other using
Multiprotocol Border Gateway Protocol (MP-BGP) and allocate MPLS labels to
IPv6 prefixes.
●
6PE routers exchange IPv4 routing information with Ps using IPv4 routing
protocols and establish LSPs between 6PE routers and Ps using MPLS.
Figure 2-13 Packet forwarding using MPLS 6PE
CE
IPv4/MPLS
backbone network
6PE
6PE
CE
MP-BGP
IPv6
site
IPv6
IPv6
site
P
L1
L2 IPv6
L2 IPv6
IPv6
Figure 2-13 shows the IPv6 packet forwarding process on an MPLS 6PE network.
IPv6 packets must carry outer and inner labels when being forwarded on the IPv4
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backbone network. The inner label (L2) maps the IPv6 prefix, while the outer label
(L1) maps the LSP between 6PEs.
The MPLS 6PE technology allows ISPs to connect existing IPv4/MPLS networks to
IPv6 networks by simply upgrading PEs. To Internet service providers (ISPs), the
MPLS 6PE technology is an efficient solution for transition to IPv6.
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3 Static LSP Configuration
Static LSP Configuration
About This Chapter
This chapter describes how to configure static label switched paths (LSPs). Static
LSPs can be set up by manually allocating labels to label switching routers (LSRs).
Static LSPs apply to networks with simple and stable network topologies.
3.1 Overview of Static LSPs
3.2 Licensing Requirements and Limitations for Static LSPs
3.3 Default Settings for Static LSPs
3.4 Creating Static LSPs
3.5 Configuring Static BFD for Static LSPs
3.6 Verifying the LSP Connectivity
3.7 Configuration Examples for Static LSPs
3.1 Overview of Static LSPs
Static LSPs are manually set up by an administrator and apply to networks with
simple and stable network topologies. They cannot be set up using a label
distribution protocol.
As shown in Figure 3-1, the path through which IP packets are transmitted on an
MPLS network is called label switched path (LSP). An LSP can be manually
configured or established using label distribution protocols.
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Figure 3-1 Networking of MPLS
CE
VPN 1
Site
PE
CE
VPN 2
Site
CE
VPN 1
Site
IP/MPLS backbone
network
LSP
PE
P
P
VPN 2
Site
CE
PE
PE
PE
Generally, MPLS uses the Label Distribution Protocol (LDP) to set up LSPs. LDP
uses routing information to set up LSPs. If LDP does not work properly, MPLS
traffic may be lost. Static LSPs are configured to determine the transmission path
of some key data or important services.
A static LSP is set up without using any label distribution protocol to exchange
control packets, so the static LSP consumes few resources. However, a static LSP
cannot vary with the network topology dynamically, and must be adjusted by an
administrator according to the network topology. The static LSP applies to
networks with simple and stable network topologies.
When configuring a static LSP, the administrator needs to manually allocate labels
for each Label Switching Router (LSR) in compliance with the following rule: the
value of the outgoing label of the previous node is equal to the value of the
incoming label of the next node.
In Figure 3-1, a static LSP is set up on the backbone network so that L2VPN or
L3VPN services can be easily deployed.
3.2 Licensing Requirements and Limitations for Static
LSPs
Involved Network Elements
Other network elements are not required.
License Requirements
Static LSP is a basic feature of a switch and is not under license control.
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Version Requirements
Table 3-1 Products and versions supporting static LSPs
Produ
ct
Product
Model
Software Version
S1700
S1720GFR
Not supported
S1720GW,
S1720GWR
Not supported
S1720GW-E,
S1720GWRE
Not supported
S1720X,
S1720X-E
Not supported
Other
S1700
models
Models that cannot be configured using commands. For
details about features and versions, see S1700
Documentation Bookshelf.
S2700SI
Not supported
S2700EI
Not supported
S2710SI
Not supported
S2720EI
Not supported
S2750EI
Not supported
S3700SI,
S3700EI
Not supported
S3700HI
Not supported
S5700LI
Not supported
S5700S-LI
Not supported
S5710-C-LI
Not supported
S5710-X-LI
Not supported
S5700SI
Not supported
S5700EI
Not supported
S5710EI
V200R002C00, V200R003C00, V200R005(C00&C02)
S5720EI
V200R009C00, V200R010C00, V200R011C00,
V200R011C10
S5720LI,
S5720S-LI
Not supported
S2700
S3700
S5700
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Produ
ct
S6700
3 Static LSP Configuration
Product
Model
Software Version
S5720SI,
S5720S-SI
Not supported
S5700HI
V200R001(C00&C01), V200R002C00, V200R003C00,
V200R005(C00SPC500&C01&C02)
S5710HI
V200R003C00, V200R005(C00&C02&C03)
S5720HI
V200R007C10, V200R009C00, V200R010C00,
V200R011C00, V200R011C10
S5730SI
Not supported
S5730S-EI
Not supported
S6720LI,
S6720S-LI
Not supported
S6720SI,
S6720S-SI
Not supported
S6700EI
V200R005(C00&C01&C02)
S6720EI
V200R008C00, V200R009C00, V200R010C00,
V200R011C00, V200R011C10
S6720S-EI
V200R009C00, V200R010C00, V200R011C00,
V200R011C10
To know details about software mappings, see Hardware Query Tool.
Feature Limitations
On the S5720EI switch, if hardware support for MPLS is displayed as NO in the
output of the display device capability command, the switch does not support
MPLS. In this case, you need to pay attention to the following points:
●
MPLS cannot be enabled on the S5720EI switch. If the switch has been added
to a stack, MPLS cannot be enabled on the stack.
●
The S5720EI switch cannot be added to a stack running MPLS.
3.3 Default Settings for Static LSPs
Table 3-2 Default settings for static LSPs
Parameter
Default Setting
Global MPLS capability
Disabled
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Parameter
Default Setting
Global BFD capability
Disabled
3.4 Creating Static LSPs
Pre-configuration Tasks
Before creating static LSPs, configure a static unicast route or an IGP to connect
LSRs at the network layer.
Configuration Procedure
Create static LSPs according to the following sequence.
3.4.1 Configuring LSR ID
Context
An LSR ID identifies an LSR on a network. An LSR does not have the default LSR
ID, and you must configure an LSR ID for it. To enhance network reliability, you
are advised to use the IP address of a loopback interface on the LSR as the LSR ID.
Perform the following steps on each node in an MPLS domain.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls lsr-id lsr-id
The LSR ID of the local node is configured.
By default, no LSR ID is set.
----End
Follow-up Procedure
Before changing the configured LSP ID, run the undo mpls command in the
system view.
NOTICE
Running the undo mpls command to delete all MPLS configurations will interrupt
MPLS services, so plan the LSR ID of each LSP uniformly to prevent LSR ID change.
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3.4.2 Enabling MPLS
Context
Perform the following steps on each LSR in an MPLS domain:
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
MPLS is enabled globally and the MPLS view is displayed.
By default, no node is enabled with MPLS.
Step 3 Run quit
Return to the system view.
Step 4 Run interface interface-type interface-number
The interface to participate in MPLS forwarding is specified.
Step 5 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 6 Run mpls
MPLS is enabled on the interface.
By default, no interface is enabled with MPLS.
----End
3.4.3 Establishing a Static LSP
Context
Static LSPs and static Constraint-based Routed LSPs (CR-LSPs) share the same
label space (16-1023). Note that the value of the outgoing label of the previous
node is equal to the value of the incoming label of the next node.
Perform the following operations on the ingress, transit, and egress nodes of the
static LSP. Figure 3-2 shows planned labels.
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Figure 3-2 Networking of establishing a static LSP
In Label
200
Loopback1
Loopback1
Loopback1
GE0/0/1 3.3.3.9/32
GE0/0/1 2.2.2.9/32 GE0/0/2
1.1.1.9/32 GE0/0/1
VLANIF200
VLANIF100 VLANIF100
VLANIF200
172.16.1.1/24 172.16.1.2/24
172.20.1.1/24 172.20.1.2/24
Out Label
100
In/Out Label
100/200
Ingress
Transit
Egress
LSP1
Procedure
Step 1 Configure the ingress node.
1.
Run system-view
The system view is displayed.
2.
Run static-lsp ingress lsp-name destination ip-address { mask-length |
mask } { nexthop next-hop-address | outgoing-interface interface-type
interface-number } * out-label out-label
The local node is configured as the ingress node of a specified LSP.
You are advised to set up a static LSP by specifying a next hop. Ensure that
the local routing table contains the route entries, including the destination IP
address and the next hop IP addresses of the LSP to be set up.
If an Ethernet interface is used as an outbound interface of an LSP, the
nexthop next-hop-address parameter must be configured.
As shown in Figure 3-2, the LSP name is LSP1, destination address is
3.3.3.9/32, next hop address is 172.16.1.2, outbound interface is Vlanif100,
and outgoing label is 100.
Step 2 Configure the transit node.
1.
Run system-view
The system view is displayed.
2.
Run static-lsp transit lsp-name [ incoming-interface interface-type
interface-number ] in-label in-label { nexthop next-hop-address | outgoinginterface interface-type interface-number } * out-label out-label
The local node is configured as the transit node of a specified LSP.
You are advised to set up a static LSP by specifying a next hop address. In
addition, ensure that the local routing table contains the route entries,
including the destination IP address and the next hop IP address of the LSP to
be set up.
If an Ethernet interface is used as an outbound interface of an LSP, the
nexthop next-hop-address parameter must be configured.
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As shown in Figure 3-2, the LSP name is LSP1, the inbound interface is
Vlanif100, incoming label is 100, next hop address is 172.20.1.2, outbound
interface is Vlanif200, and outgoing label is 200.
Step 3 Configure the egress node.
1.
Run system-view
The system view is displayed.
2.
Run static-lsp egress lsp-name [ incoming-interface interface-type
interface-number ] in-label in-label [ lsrid ingress-lsr-id tunnel-id tunnel-id ]
The local node is configured as the egress node of a specified LSP.
As shown in Figure 3-2, the LSP name is LSP1, the inbound interface is
Vlanif200, and incoming label is 200.
----End
3.4.4 Verifying the Static LSP Configuration
Prerequisites
The configurations of the static LSP function are complete.
Procedure
●
Run the display default-parameter mpls management command to check
default configurations of the MPLS management module.
●
Run the display mpls static-lsp [ lsp-name ] [ { include | exclude } ipaddress mask-length ] [ verbose ] command to check the static LSP.
●
Run the display mpls label static available [ [ label-from label-index ]
label-number label-number ] command to check information about labels
available for transmitting static services.
----End
3.5 Configuring Static BFD for Static LSPs
When configuring static BFD for static LSPs, pay attention to the following points:
●
A static BFD session can be created for non-host routes. When the static LSP
becomes Down, the associated BFD session also becomes Down. When the
static LSP goes Up, a BFD session is reestablished.
●
The forwarding modes on the forwarding path and reverse path can be
different (for example, an IP packet is sent from the source to the destination
through an LSP, and is sent from the destination to the source in IP
forwarding mode), but the forwarding path and reverse path must be
established over the same link. If they use different links, BFD cannot identify
the faulty path when a fault is detected.
By configuring static BFD for static LSPs, you can check connectivity of static LSPs.
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Pre-configuration Tasks
Before configuring static BFD for static LSP, create static LSPs. For details, see 3.4
Creating Static LSPs.
Configuration Procedure
Configure static BFD for static LSPs according to the following sequence.
3.5.1 Configuring BFD with Specific Parameters on the Ingress
Node
Context
BFD parameters on the ingress node include the local and remote discriminators,
minimum intervals for sending and receiving BFD packets, and local BFD detection
multiplier. The BFD parameters affect BFD session setup.
You can adjust the local detection time according to the network situation. On an
unstable link, if a small detection time is used, a BFD session may flap. You can
increase the detection time of the BFD session.
Actual interval for the local device to send BFD packets = MAX {locally configured interval
for sending BFD packets, remotely configured interval for receiving BFD packets}
Actual interval for the local device to receive BFD packets = MAX {remotely configured
interval for sending BFD packets, locally configured interval for receiving BFD packets}
Local detection time = Actual interval for receiving BFD packets x Remotely configured BFD
detection multiplier
Perform the following steps on the ingress node of the static LSP.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run bfd
This node is enabled with the global BFD function. The global BFD view is
displayed.
By default, global BFD is disabled.
Step 3 Run quit
Return to the system view.
Step 4 Run bfd cfg-name bind static-lsp lsp-name
The BFD session is bound to the static LSP.
Step 5 Set local and remote discriminators of a BFD session.
●
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Run discriminator local discr-value
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The local discriminator is configured.
●
Run discriminator remote discr-value
The remote discriminator is configured.
The local and remote discriminators of the two ends on a BFD session must be correctly
associated. That is, the local discriminator of the local device and the remote discriminator
of the remote device are the same, and the remote discriminator of the local device and the
local discriminator of the remote device are the same. Otherwise, the BFD session cannot
be correctly set up. In addition, the local and remote discriminators cannot be modified
after being successfully configured.
Step 6 (Optional) Run min-tx-interval interval
The interval for sending BFD packets is set on the local device.
Step 7 (Optional) Run min-rx-interval interval
The interval for receiving BFD packets is set on the local device.
Step 8 (Optional) Run detect-multiplier multiplier
The local BFD detection multiplier is set.
By default, the value is 3.
Step 9 Run process-pst
The changes of the BFD session status can be advertised to the upper-layer
application.
By default, a static BFD session cannot report faults of the monitored service
module to the system.
Step 10 Run commit
The configuration is committed.
----End
3.5.2 Configuring BFD with Specific Parameters on the Egress
Node
Context
BFD parameters on the egress node include the local and remote discriminators,
minimum intervals for sending and receiving BFD packets, and local BFD detection
multiplier. The BFD parameters affect BFD session setup.
You can adjust the local detection time according to the network situation. On an
unstable link, if a small detection time is used, a BFD session may flap. You can
increase the detection time of the BFD session.
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Actual interval for the local device to send BFD packets = MAX {locally configured interval
for sending BFD packets, remotely configured interval for receiving BFD packets}
Actual interval for the local device to receive BFD packets = MAX {remotely configured
interval for sending BFD packets, locally configured interval for receiving BFD packets}
Local detection time = Actual interval for receiving BFD packets x Remotely configured BFD
detection multiplier
Perform the following steps on the egress node of the LSP.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run bfd
This node is enabled with the global BFD function. The global BFD view is
displayed.
By default, global BFD is disabled.
Step 3 Run quit
Return to the system view.
Step 4 The IP link, LSP, or TE tunnel can be used as the reverse tunnel to inform the
egress node of a fault. To ensure that BFD packets are received and sent along the
same path, an LSP or TE tunnel is preferentially used to inform the egress node of
an LSP fault. If the configured reverse tunnel requires BFD detection, configure a
pair of BFD sessions for it. Run one of the following commands as required.
●
For the IP link, run bfd cfg-name bind peer-ip peer-ip [ vpn-instance vpninstance-name ] [ interface interface-type interface-number ] [ source-ip
source-ip ]
●
For the dynamic LSP, run bfd cfg-name bind ldp-lsp peer-ip ip-address
nexthop ip-address [ interface interface-type interface-number ]
●
For the static LSP, run bfd cfg-name bind static-lsp lsp-name
●
For MPLS TE, run bfd cfg-name bind mpls-te interface tunnel interfacenumber [ te-lsp [ backup ] ]
Step 5 Set local and remote discriminators of a BFD session.
●
Run discriminator local discr-value
The local discriminator is configured.
●
Run discriminator remote discr-value
The remote discriminator is configured.
The local and remote discriminators of the two ends on a BFD session must be correctly
associated. That is, the local discriminator of the local device and the remote discriminator
of the remote device are the same, and the remote discriminator of the local device and the
local discriminator of the remote device are the same. Otherwise, the BFD session cannot
be correctly set up. In addition, the local and remote discriminators cannot be modified
after being successfully configured.
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Step 6 (Optional) Run min-tx-interval interval
The interval for sending BFD packets is set on the local device.
Step 7 (Optional) Run min-rx-interval interval
The interval for receiving BFD packets is set on the local device.
Step 8 (Optional) Run detect-multiplier multiplier
The local BFD detection multiplier is set.
By default, the value is 3.
Step 9 (Optional) Run process-pst
The changes of the BFD session status can be advertised to the upper-layer
application.
By default, a static BFD session cannot report faults of the monitored service
module to the system.
If an LSP is used as a reverse tunnel to notify the ingress of a fault, you can run
this command to allow the reverse tunnel to switch traffic if the BFD session goes
Down. If a single-hop IP link is used as a reverse tunnel, this command can be
configured. Because the process-pst command can be only configured for BFD
single-link detection.
Step 10 Run commit
The configuration is committed.
----End
3.5.3 Verifying the Configuration of Static BFD for Static LSPs
Prerequisites
The configurations of the static BFD for static LSP function are complete.
Procedure
●
Run the display bfd configuration { all | static } command to check the BFD
configuration.
●
Run the display bfd session { all | static } command to check information
about the BFD session.
●
Run the display bfd statistics session { all | static } command to check
statistics about BFD sessions.
●
Run the display mpls static-lsp [ lsp-name ] [ { include | exclude } ipaddress mask-length ] [ verbose ] command to check the status of the static
LSP.
----End
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3.6 Verifying the LSP Connectivity
Context
In MPLS, the control panel used for setting up an LSP cannot detect data
forwarding failures on the LSP. This makes network maintenance difficult.
MPLS ping checks LSP connectivity, and MPLS traceroute locates network faults in
addition to checking LSP connectivity.
MPLS ping and MPLS traceroute can be performed in any view. MPLS ping and
MPLS traceroute do not support packet fragmentation.
Procedure
Step 1 Run the system-view command to enter the system view.
Step 2 Run the lspv mpls-lsp-ping echo enable command to enable the response to
MPLS Echo Request packets.
By default, the device is enabled to respond to MPLS Echo Request packets.
Step 3 (Optional) Run the lspv packet-filter acl-number command to enable MPLS Echo
Request packet filtering based on source IP addresses. The filtering rule is specified
in the ACL.
By default, the device does not filter MPLS Echo Request packets based on their
source IP addresses.
Step 4 Run the following command to check the LSP connectivity.
●
Run the ping lsp [ -a source-ip | -c count | -exp exp-value | -h ttl-value | -m
interval | -r reply-mode | -s packet-size | -t time-out | -v ] * ip destinationaddress mask-length [ ip-address ] [ nexthop nexthop-address | draft6 ]
command to perform an MPLS ping test.
If draft6 is specified, the command is implemented according to draft-ietfmpls-lsp-ping-06. By default, the command is implemented according to RFC
4379.
●
Run the tracert lsp [ -a source-ip | -exp exp-value | -h ttl-value | -r replymode | -t time-out | -v ] * ip destination-address mask-length [ ip-address ]
[ nexthop nexthop-address | draft6 ] command to perform an MPLS
traceroute test.
If draft6 is specified, the command is implemented according to draft-ietfmpls-lsp-ping-06. By default, the command is implemented according to RFC
4379.
----End
Follow-up Procedure
●
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Run the display lspv statistics command to check the LSPV test statistics. A
large amount of statistical information is saved in the system after MPLS ping
or traceroute tests are performed multiple times, which is unhelpful for
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problem analysis. To obtain more accurate statistics, run the reset lspv
statistics command to clear LSPV test statistics before running the display
lspv statistics command.
●
Run the undo lspv mpls-lsp-ping echo enable command to disable response
to MPLS Echo Request packets. It is recommended that you run this command
after completing an MPLS ping or traceroute test to save system resources.
●
Run the display lspv configuration command to check the current LSPV
configuration.
3.7 Configuration Examples for Static LSPs
3.7.1 Example for Configuring Static LSPs
Networking Requirements
As shown in Figure 3-3, the network topology is simple and stable, and LSR_1,
LSR_2, and LSR_3 are MPLS backbone network devices. A stable public tunnel
needs to be created on the backbone network to transmit L2VPN or L3VPN
services.
Figure 3-3 Networking diagram for establishing static LSPs
Loopback1
Loopback1
GE0/0/1 2.2.2.9/32 GE0/0/2
1.1.1.9/32 GE0/0/1
VLANIF100 VLANIF100
VLANIF200
172.1.1.1/24 172.1.1.2/24
172.2.1.1/24
LSR_1
LSR_2
Loopback1
GE0/0/1 3.3.3.9/32
VLANIF200
172.2.1.2/24
LSR_3
Configuration Roadmap
You can configure static LSPs to meet the requirement. Configure two static LSPs:
LSP1 from LSR_1 to LSR_3 with LSR_1, LSR_2, and LSR_3 as the ingress, transit,
and egress nodes respectively, and LSP2 from LSR_3 to LSR_1 with LSR_3, LSR_2,
and LSR_1 as the ingress, transit, and egress nodes respectively. The configuration
roadmap is as follows:
1.
Configure OSPF on the LSRs to ensure IP connectivity on the backbone
network.
2.
Configure MPLS on LSRs, which is the prerequisite for creating a public tunnel
on the backbone network.
3.
Configure static LSPs because a stable public tunnel needs to be created on
the backbone network with simple and stable network topology to transmit
L2VPN and L3VPN services. Perform the following operations:
a.
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Configure the destination IP address, next hop, value of the outgoing
label for the LSP on the ingress node.
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b.
Configure the inbound interface, value of the incoming label equivalent
to the outgoing label of the last node, and next hop and value of the
outgoing label of the LSP on the transit node.
c.
Configure the inbound interface and value of the incoming label
equivalent to the outgoing label of the last node of the LSP on the egress
node.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
# Configure LSR_1. The configurations of LSR_2 and LSR_3 are similar to the
configuration of LSR_1, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSR_1
[LSR_1] interface loopback 1
[LSR_1-LoopBack1] ip address 1.1.1.9 32
[LSR_1-LoopBack1] quit
[LSR_1] vlan batch 100
[LSR_1] interface vlanif 100
[LSR_1-Vlanif100] ip address 172.1.1.1 24
[LSR_1-Vlanif100] quit
[LSR_1] interface gigabitethernet 0/0/1
[LSR_1-GigabitEthernet0/0/1] port link-type trunk
[LSR_1-GigabitEthernet0/0/1] port trunk allow-pass vlan 100
[LSR_1-GigabitEthernet0/0/1] quit
Step 2 Configure OSPF to advertise the network segments that the interfaces are
connected to and the host route of the LSR ID.
# Configure LSR_1.
[LSR_1] ospf 1
[LSR_1-ospf-1] area 0
[LSR_1-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSR_1-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[LSR_1-ospf-1-area-0.0.0.0] quit
[LSR_1-ospf-1] quit
# Configure LSR_2.
[LSR_2] ospf 1
[LSR_2-ospf-1] area 0
[LSR_2-ospf-1-area-0.0.0.0]
[LSR_2-ospf-1-area-0.0.0.0]
[LSR_2-ospf-1-area-0.0.0.0]
[LSR_2-ospf-1-area-0.0.0.0]
[LSR_2-ospf-1] quit
network 2.2.2.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.2.1.0 0.0.0.255
quit
# Configure LSR_3.
[LSR_3] ospf 1
[LSR_3-ospf-1] area 0
[LSR_3-ospf-1-area-0.0.0.0] network 3.3.3.9 0.0.0.0
[LSR_3-ospf-1-area-0.0.0.0] network 172.2.1.0 0.0.0.255
[LSR_3-ospf-1-area-0.0.0.0] quit
[LSR_3-ospf-1] quit
After the configuration is complete, run the display ip routing-table command
on each node, and you can view that the nodes learn routes from each other.
Step 3 Enable basic MPLS functions on each node.
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# Configure LSR_1.
[LSR_1] mpls lsr-id 1.1.1.9
[LSR_1] mpls
[LSR_1-mpls] quit
# Configure LSR_2.
[LSR_2] mpls lsr-id 2.2.2.9
[LSR_2] mpls
[LSR_2-mpls] quit
# Configure LSR_3.
[LSR_3] mpls lsr-id 3.3.3.9
[LSR_3] mpls
[LSR_3-mpls] quit
Step 4 Enable MPLS on each VLANIF interface.
# Configure LSR_1.
[LSR_1] interface vlanif 100
[LSR_1-Vlanif100] mpls
[LSR_1-Vlanif100] quit
# Configure LSR_2.
[LSR_2] interface vlanif 100
[LSR_2-Vlanif100] mpls
[LSR_2-Vlanif100] quit
[LSR_2] interface vlanif 200
[LSR_2-Vlanif200] mpls
[LSR_2-Vlanif200] quit
# Configure LSR_3.
[LSR_3] interface vlanif 200
[LSR_3-Vlanif200] mpls
[LSR_3-Vlanif200] quit
Step 5 Configure a static LSP from LSR_1 to LSR_3.
# Configure ingress node LSR_1.
[LSR_1] static-lsp ingress LSP1 destination 3.3.3.9 32 nexthop 172.1.1.2 out-label 20
# Configure transit node LSR_2.
[LSR_2] static-lsp transit LSP1 incoming-interface vlanif 100 in-label 20 nexthop 172.2.1.2 out-label 40
# Configure egress node LSR_3.
[LSR_3] static-lsp egress LSP1 incoming-interface vlanif 200 in-label 40
After the configuration is complete, run the display mpls static-lsp command on
each node to check the status of the static LSP. Use the command output on
LSR_1 as an example.
[LSR_1] display mpls static-lsp
TOTAL
:1
STATIC LSP(S)
UP
:1
STATIC LSP(S)
DOWN
:0
STATIC LSP(S)
Name
FEC
I/O Label I/O If
LSP1
3.3.3.9/32
NULL/20 -/Vlanif100
Status
Up
The LSP is unidirectional, you need to configure a static LSP from LSR_3 to LSR_1.
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Step 6 Configure a static LSP from LSR_3 to LSR_1.
# Configure ingress node LSR_3.
[LSR_3] static-lsp ingress LSP2 destination 1.1.1.9 32 nexthop 172.2.1.1 out-label 30
# Configure transit node LSR_2.
[LSR_2] static-lsp transit LSP2 incoming-interface vlanif 200 in-label 30 nexthop 172.1.1.1 out-label 60
# Configure egress node LSR_1.
[LSR_1] static-lsp egress LSP2 incoming-interface vlanif 100 in-label 60
Step 7 Verify the configuration.
After the configuration is complete, run the display mpls static-lsp or display
mpls static-lsp verbose command on each node to check the status and detailed
information about the static LSP. Use the command output on LSR_3 as an
example.
[LSR_3] display mpls static-lsp
TOTAL
:2
STATIC LSP(S)
UP
:2
STATIC LSP(S)
DOWN
:0
STATIC LSP(S)
Name
FEC
I/O Label I/O If
LSP1
-/40/NULL Vlanif200/LSP2
1.1.1.9/32
NULL/30 -/Vlanif200
[LSR_3] display mpls static-lsp verbose
No
:1
LSP-Name
: LSP1
LSR-Type
: Egress
FEC
: -/In-Label
: 40
Out-Label
: NULL
In-Interface : Vlanif200
Out-Interface : NextHop
:Static-Lsp Type: Normal
Lsp Status
: Up
Status
Up
Up
No
:2
LSP-Name
: LSP2
LSR-Type
: Ingress
FEC
: 1.1.1.9/32
In-Label
: NULL
Out-Label
: 30
In-Interface : Out-Interface : Vlanif200
NextHop
: 172.2.1.1
Static-Lsp Type: Normal
Lsp Status
: Up
Run the ping lsp ip 1.1.1.9 32 command on LSR_3. The command output shows
that the static LSP can be pinged.
Run the ping lsp ip 3.3.3.9 32 command on LSR_1. The command output shows
that the static LSP can be pinged.
----End
Configuration Files
●
LSR_1 configuration file
#
sysname LSR_1
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#
vlan batch 100
#
mpls lsr-id 1.1.1.9
mpls
#
interface Vlanif100
ip address 172.1.1.1 255.255.255.0
mpls
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 172.1.1.0 0.0.0.255
#
static-lsp ingress LSP1 destination 3.3.3.9 32 nexthop 172.1.1.2 out-label 20
static-lsp egress LSP2 incoming-interface Vlanif100 in-label 60
#
return
●
LSR_2 configuration file
#
sysname LSR_2
#
vlan batch 100 200
#
mpls lsr-id 2.2.2.9
mpls
#
interface Vlanif100
ip address 172.1.1.2 255.255.255.0
mpls
#
interface Vlanif200
ip address 172.2.1.1 255.255.255.0
mpls
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 200
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.2.1.0 0.0.0.255
#
static-lsp transit LSP1 incoming-interface Vlanif100 in-label 20 nexthop 172.2.1.2 out-label 40
static-lsp transit LSP2 incoming-interface Vlanif200 in-label 30 nexthop 172.1.1.1 out-label 60
#
return
●
LSR_3 configuration file
#
sysname LSR_3
#
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vlan batch 200
#
mpls lsr-id 3.3.3.9
mpls
#
interface Vlanif200
ip address 172.2.1.2 255.255.255.0
mpls
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 200
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 172.2.1.0 0.0.0.255
#
static-lsp egress LSP1 incoming-interface Vlanif200 in-label 40
static-lsp ingress LSP2 destination 1.1.1.9 32 nexthop 172.2.1.1 out-label 30
#
return
3.7.2 Example for Configuring Static BFD to Monitor Static
LSPs
Networking Requirements
As shown in Figure 3-4, PEs and Ps are backbone network devices, and static LSPs
have been set up on the backbone network to transmit network services.
Network services, such as VoIP, online game, and online video service, have high
requirements for real-timeness. Data loss caused by faulty links will seriously
affect services. It is required that services be fast switched to the backup LSP when
the primary LSP becomes faulty, minimizing packet loss. Static BFD for static LSPs
is configured to fast detect static LSPs.
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
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3 Static LSP Configuration
Figure 3-4 Networking diagram for establishing static LSPs
Loopback1
2.2.2.9/32
G
VL E0
/1 0
0
/
A
0 10
17 N /0/2
2.2 IF2
GE NIF 2/24
.1. 00
A .1.
L
1/2
G
V 2.1
1
/
VL E0/
4
/0 00 17
0
A
P_1
17 N 0/1 Loopback1
Loopback1 GE NIF1 /24
2.2 IF2
1
.1. 00 4.4.4.9/32
1.1.1.9/32 VLA 1.1.
2/2
.
2
4
Primary LSP
17
G
PE_1 VL E0/
A
17 N 0/2
2.3 IF3
.1. 00
1/2
4
Backup LSP
G
VL E0/
A
17 NI 0/1
2.3 F3
.1. 00
2/2
4
P_2
Loopback1
3.3.3.9/32
PE_2
2
/0/ 00
0
4
GE NIF 2/24
A .1.
L
V .4
2
/0/ 00 172
0
GE NIF4 /24
A
.1
VL .4.1
2
17
Configuration Roadmap
The configuration roadmap is as follows:
1.
Configure OSPF between the PEs and P to implement IP connectivity on the
backbone network.
2.
Configure static LSPs on PEs and P to transmit network services.
3.
Configure static BFD on PEs to fast detect static LSPs. This is because faults on
static LSPs can only be detected by static BFD.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
# Configure PE_1. The configurations of P_1, P_2, and PE_2, are similar to the
configuration of PE_1, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname PE_1
[PE_1] interface loopback 1
[PE_1-LoopBack1] ip address 1.1.1.9 32
[PE_1-LoopBack1] quit
[PE_1] vlan batch 100 300
[PE_1] interface vlanif 100
[PE_1-Vlanif100] ip address 172.1.1.1 24
[PE_1-Vlanif100] quit
[PE_1] interface vlanif 300
[PE_1-Vlanif300] ip address 172.3.1.1 24
[PE_1-Vlanif300] quit
[PE_1] interface gigabitethernet0/0/1
[PE_1-GigabitEthernet0/0/1] port link-type trunk
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[PE_1-GigabitEthernet0/0/1] port trunk allow-pass vlan 100
[PE_1-GigabitEthernet0/0/1] quit
[PE_1] interface gigabitethernet0/0/2
[PE_1-GigabitEthernet0/0/2] port link-type trunk
[PE_1-GigabitEthernet0/0/2] port trunk allow-pass vlan 300
[PE_1-GigabitEthernet0/0/2] quit
Step 2 Configure OSPF to advertise the network segments that the interfaces are
connected to and the host route of the LSR ID.
# Configure PE_1. The configurations of P_1, P_2, and PE_2, are similar to the
configuration of PE_1, and are not mentioned here.
[PE_1] ospf 1
[PE_1-ospf-1] area 0
[PE_1-ospf-1-area-0.0.0.0]
[PE_1-ospf-1-area-0.0.0.0]
[PE_1-ospf-1-area-0.0.0.0]
[PE_1-ospf-1-area-0.0.0.0]
[PE_1-ospf-1] quit
network 1.1.1.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.3.1.0 0.0.0.255
quit
Step 3 Set the cost of VLANIF 300 on PE_1 to 1000.
[PE_1] interface vlanif 300
[PE_1-Vlanif300] ospf cost 1000
[PE_1-Vlanif300] quit
After the configuration is complete, run the display ip routing-table command
on each node. You can see that the nodes learn routes from each other. The
outbound interface of the route from PE_1 to PE_2 is VLANIF 100.
Step 4 Enable basic MPLS functions on each node.
# Configure PE_1.
[PE_1] mpls lsr-id 1.1.1.9
[PE_1] mpls
[PE_1-mpls] quit
# Configure P_1.
[P_1] mpls lsr-id 2.2.2.9
[P_1] mpls
[P_1-mpls] quit
# Configure P_2.
[P_2] mpls lsr-id 3.3.3.9
[P_2] mpls
[P_2-mpls] quit
# Configure PE_2.
[PE_2] mpls lsr-id 4.4.4.9
[PE_2] mpls
[PE_2-mpls] quit
Step 5 Enable MPLS on each VLANIF interface.
# Configure PE_1.
[PE_1] interface vlanif 100
[PE_1-Vlanif100] mpls
[PE_1-Vlanif100] quit
[PE_1] interface vlanif 300
[PE_1-Vlanif300] mpls
[PE_1-Vlanif300] quit
# Configure P_1.
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[P_1] interface vlanif 100
[P_1-Vlanif100] mpls
[P_1-Vlanif100] quit
[P_1] interface vlanif 200
[P_1-Vlanif200] mpls
[P_1-Vlanif200] quit
# Configure P_2.
[P_2] interface vlanif 300
[P_2-Vlanif300] mpls
[P_2-Vlanif300] quit
[P_2] interface vlanif 400
[P_2-Vlanif400] mpls
[P_2-Vlanif400] quit
# Configure PE_2.
[PE_2] interface vlanif 200
[PE_2-Vlanif200] mpls
[PE_2-Vlanif200] quit
[PE_2] interface vlanif 400
[PE_2-Vlanif400] mpls
[PE_2-Vlanif400] quit
Step 6 Create a static LSP named LSP1 with PE_1 being the ingress node, P_1 being the
transit node, and PE_2 being the egress node.
# Configure ingress node PE_1.
[PE_1] static-lsp ingress LSP1 destination 4.4.4.9 32 nexthop 172.1.1.2 out-label 20
# Configure transit node P_1.
[P_1] static-lsp transit LSP1 incoming-interface vlanif 100 in-label 20 nexthop 172.2.1.2 out-label 40
# Configure egress node PE_2.
[PE_2] static-lsp egress LSP1 incoming-interface vlanif 200 in-label 40
Step 7 Create a static LSP named LSP2 with PE_1 being the ingress node, P_2 being the
transit node, and PE_2 being the egress node.
# Configure ingress node PE_1.
[PE_1] static-lsp ingress LSP2 destination 4.4.4.9 32 nexthop 172.3.1.2 out-label 30
# Configure transit node P_2.
[P_2] static-lsp transit LSP2 incoming-interface vlanif 300 in-label 30 nexthop 172.4.1.2 out-label 60
# Configure egress node PE_2.
[PE_2] static-lsp egress LSP2 incoming-interface vlanif 400 in-label 60
After the configuration is complete, run the ping lsp ip 4.4.4.9 32 command on
PE_1. The command output shows that the LSP can be pinged.
Run the display mpls static-lsp verbose command on each node to check the
detailed information about the static LSP. Use the command output on PE_1 as an
example.
[PE_1] display mpls static-lsp verbose
No
:1
LSP-Name
: LSP1
LSR-Type
: Ingress
FEC
: 4.4.4.9/32
In-Label
: NULL
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3 Static LSP Configuration
Out-Label
: 20
In-Interface : Out-Interface : Vlanif100
NextHop
: 172.1.1.2
Static-Lsp Type: Normal
Lsp Status
: Up
No
:2
LSP-Name
: LSP2
LSR-Type
: Ingress
FEC
: 4.4.4.9/32
In-Label
: NULL
Out-Label
: 30
In-Interface : Out-Interface : Vlanif300
NextHop
: 172.3.1.2
Static-Lsp Type: Normal
Lsp Status
: Down
Step 8 Configure the BFD session to detect static LSP LSP1.
# On ingress node PE_1, configure a BFD session, with the local discriminator of 1,
the remote discriminator of 2, and the intervals for sending and receiving packets
of 100 ms. The port state table (PST) can be modified.
[PE_1] bfd
[PE_1-bfd] quit
[PE_1] bfd pe1tope2 bind static-lsp LSP1
[PE_1-bfd-lsp-session-pe1tope2] discriminator local 1
[PE_1-bfd-lsp-session-pe1tope2] discriminator remote 2
[PE_1-bfd-lsp-session-pe1tope2] min-tx-interval 100
[PE_1-bfd-lsp-session-pe1tope2] min-rx-interval 100
[PE_1-bfd-lsp-session-pe1tope2] process-pst
[PE_1-bfd-lsp-session-pe1tope2] commit
[PE_1-bfd-lsp-session-pe1tope2] quit
# On egress node PE_2, configure a BFD session to notify PE_1 of faults on the
static LSP.
[PE_2] bfd
[PE_2-bfd] quit
[PE_2] bfd pe2tope1 bind peer-ip 1.1.1.9
[PE_2-bfd-session-pe2tope1] discriminator local 2
[PE_2-bfd-session-pe2tope1] discriminator remote 1
[PE_2-bfd-session-pe2tope1] min-tx-interval 100
[PE_2-bfd-session-pe2tope1] min-rx-interval 100
[PE_2-bfd-session-pe2tope1] commit
[PE_2-bfd-session-pe2tope1] quit
# Run the display bfd session all command on PE_1 to check the configuration.
The command output shows that the BFD session on PE_1 is Up.
[PE_1] display bfd session all
-------------------------------------------------------------------------------Local Remote
PeerIpAddr
State
Type
InterfaceName
-------------------------------------------------------------------------------1
2
4.4.4.9
Up
S_STA_LSP -------------------------------------------------------------------------------Total UP/DOWN Session Number : 1/0
# Run the display bfd session all command on PE_2 to check the configuration.
[PE_2] display bfd session all
-------------------------------------------------------------------------------Local Remote
PeerIpAddr
State
Type
InterfaceName
-------------------------------------------------------------------------------2
1
1.1.1.9
Up
S_IP_PEER
-------------------------------------------------------------------------------Total UP/DOWN Session Number : 1/0
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3 Static LSP Configuration
Step 9 Verify the configuration.
# Run the shutdown command on GE0/0/2 of P_1 to simulate a fault on a static
LSP.
[P_1] interface gigabitethernet0/0/2
[P_1-GigabitEthernet0/0/2] shutdown
# Run the display bfd session all command on PE to check the status of the BFD
session.
[PE_2] display bfd session all
-------------------------------------------------------------------------------Local Remote
PeerIpAddr
State
Type
InterfaceName
-------------------------------------------------------------------------------2
1
1.1.1.9
Down
S_IP_PEER
-------------------------------------------------------------------------------Total UP/DOWN Session Number : 0/1
----End
Configuration Files
●
PE_1 configuration file
#
sysname PE_1
#
vlan batch 100 300
#
bfd
#
mpls lsr-id 1.1.1.9
mpls
#
interface Vlanif100
ip address 172.1.1.1 255.255.255.0
mpls
#
interface Vlanif300
ip address 172.3.1.1 255.255.255.0
ospf cost 1000
mpls
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 300
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.3.1.0 0.0.0.255
#
static-lsp ingress LSP1 destination 4.4.4.9 32 nexthop 172.1.1.2 out-label 20
static-lsp ingress LSP2 destination 4.4.4.9 32 nexthop 172.3.1.2 out-label 30
#
bfd pe1tope2 bind static-lsp LSP1
discriminator local 1
discriminator remote 2
min-tx-interval 100
min-rx-interval 100
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process-pst
commit
#
return
●
P_1 configuration file
#
sysname P_1
#
vlan batch 100 200
#
mpls lsr-id 2.2.2.9
mpls
#
interface Vlanif100
ip address 172.1.1.2 255.255.255.0
mpls
#
interface Vlanif200
ip address 172.2.1.1 255.255.255.0
mpls
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 200
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.2.1.0 0.0.0.255
#
static-lsp transit LSP1 incoming-interface Vlanif100 in-label 20 nexthop 172.2.1.2 out-label 40
#
return
●
P_2 configuration file
#
sysname P_2
#
vlan batch 300 400
#
mpls lsr-id 3.3.3.9
mpls
#
interface Vlanif300
ip address 172.3.1.2 255.255.255.0
mpls
#
interface Vlanif400
ip address 172.4.1.1 255.255.255.0
mpls
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 300
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 400
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
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#
ospf 1
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 172.3.1.0 0.0.0.255
network 172.4.1.0 0.0.0.255
#
static-lsp transit LSP2 incoming-interface Vlanif300 in-label 30 nexthop 172.4.1.2 out-label 60
#
return
●
PE_2 configuration file
#
sysname PE_2
#
vlan batch 200 400
#
bfd
#
mpls lsr-id 4.4.4.9
mpls
#
interface Vlanif200
ip address 172.2.1.2 255.255.255.0
mpls
#
interface Vlanif400
ip address 172.4.1.2 255.255.255.0
mpls
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 200
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 400
#
interface LoopBack1
ip address 4.4.4.9 255.255.255.255
#
bfd pe2tope1 bind peer-ip 1.1.1.9
discriminator local 2
discriminator remote 1
min-tx-interval 100
min-rx-interval 100
commit
#
ospf 1
area 0.0.0.0
network 4.4.4.9 0.0.0.0
network 172.2.1.0 0.0.0.255
network 172.4.1.0 0.0.0.255
#
static-lsp egress LSP1 incoming-interface Vlanif200 in-label 40
static-lsp egress LSP2 incoming-interface Vlanif400 in-label 60
#
return
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4
4 MPLS LDP Configuration
MPLS LDP Configuration
About This Chapter
This chapter describes how to configure Multiprotocol Label Switching Label
Distribution Protocol (MPLS LDP). MPLS LDP defines the messages and procedures
for distributing labels. MPLS LDP is used by Label Switching Routers (LSRs) to
negotiate session parameters, distribute labels, and then establish Label Switched
Paths (LSPs).
4.1 Overview of MPLS LDP
4.2 Understanding MPLS LDP
4.3 Summary of MPLS LDP Configuration Tasks
4.4 Licensing Requirements and Limitations for MPLS LDP
4.5 Default Settings for MPLS LDP
4.6 Configuring Basic Functions of MPLS LDP
4.7 Configuring LDP Extensions for Inter-Area LSPs
4.8 Configuring Static BFD to Detect an LDP LSP
4.9 Configuring Dynamic BFD for LDP LSPs
4.10 Configuring Synchronization Between LDP and IGP
4.11 Configuring LDP FRR
4.12 Configuring LDP GR
4.13 Configuring LDP Security Mechanisms
4.14 Configuring Non-labeled Public Network Routes to Be Iterated to LSPs
4.15 Maintaining MPLS LDP
4.16 Configuration Examples for MPLS LDP
4.17 Troubleshooting MPLS LDP
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4.18 FAQ About MPLS
4.1 Overview of MPLS LDP
Definition
Label Distribution Protocol (LDP) is a control protocol that functions like a
signaling protocol on traditional networks. LDP classifies forwarding equivalence
classes (FECs), distributes labels, and establishes and maintains label switched
paths (LSPs). LDP defines messages used in the label distribution process as well
as procedures for processing these messages.
Purpose
MPLS is highly scalable because it allows multiple labels to be carried on a packet
and has a connection-oriented forwarding plane. Scalability enables MPLS/IP
networks to provide various services. Label switching routers (LSRs) on MPLS
networks use the LDP protocol to map Layer 3 routing information to Layer 2
switched paths, and establish LSPs at network layers.
LDP is widely used to provide virtual private network (VPN) services due to simple
deployment and configuration, ability to establish LSPs dynamically based on
routing information, and ability to support many LSPs.
4.2 Understanding MPLS LDP
4.2.1 Basic Concepts of LDP
LDP Peers
Two LSRs that use LDP to establish an LDP session and exchange label messages
are called LDP peers. LDP peers learn labels from each other over the LDP session
between them.
LDP Adjacency
When an LSR receives a Hello message from its peer, an LDP adjacency is
established. Two types of LDP adjacencies are used:
●
Local adjacency
Discovered by multicasting a Hello message (Link Hello message).
●
Remote adjacency
Discovered by unicasting a Hello message (Targeted Hello message).
LDP maintains peer information based on adjacencies. The peer type is defined by
the type of LDP adjacency. A peer can be maintained by multiple adjacencies. If a
peer is maintained by both local and remote adjacencies, the peer type is
coexistent local and remote.
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LDP Session
LSRs exchange messages, such as label mapping and release messages, over LDP
sessions. LDP sessions are only established between LDP peers. LDP sessions are
classified into the following types:
●
Local LDP session
Established between two directly connected LSRs.
●
Remote LDP session
Established between two directly or indirectly connected LSRs.
The local and remote LDP sessions can coexist.
4.2.2 LDP Working Mechanism
4.2.2.1 LDP Messages and Process
LDP defines the label distribution process and messages transmitted during label
distribution. LSRs use LDP to map Layer 3 routing information to Layer 2 switched
paths and establish LSPs.
For details about LDP, see RFC 5036 (LDP Specification).
LDP Messages
LDP defines the following messages:
●
Discovery messages
Announce and maintain LSRs on networks. Hello messages are discovery
messages.
●
Session messages
Establish, maintain, and terminate sessions between LDP peers. Initialization
and Keepalive messages are session messages.
●
Advertisement messages
Create, modify, and delete label mappings for FECs.
●
Notification messages
Provide advisory and error information.
LDP uses the Transmission Control Protocol (TCP) to transmit Session,
Advertisement, and Notification messages to ensure reliable message
transmission. LDP uses the User Datagram Protocol (UDP) only for transmitting
Discovery messages.
LDP Process
LDP process is as follows:
1.
LDP Session Setup
After LSRs send Hello messages to discover peers, LDP sessions are
established. LDP peers then periodically send Hello and Keepalive messages to
maintain sessions.
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4 MPLS LDP Configuration
Hello messages are sent to maintain adjacency.
If an LSR does not receive a Hello message from a peer before the Hello
timer expires, the local LSR deletes the adjacency and sends a
Notification message to terminate the session.
–
Keepalive messages are sent to maintain the session.
If an LSR does not receive a Keepalive message from a peer before the
Keepalive timer expires, the local LSR terminates the TCP connection and
sends a Notification message to terminate the session.
2.
LDP LSP Setup
After sessions are established, LDP peers send Label Request and Mapping
messages to advertise FEC-to-label mappings and establish LSPs based on
mappings.
4.2.2.2 LDP Session Setup
LSRs use LDP discovery mechanisms to discover LDP peers and establish an LDP
session. An LDP LSP can be established to transmit services only after LDP sessions
are established.
LDP Discovery Mechanisms
LSRs use LDP discovery mechanisms to discover LDP peers. LSRs can use the
following types of LDP discovery mechanisms:
●
Basic discovery mechanism: discovers directly-connected LSR peers on links.
LSRs periodically send LDP Link Hello messages through the basic discovery
mechanism to establish local LDP sessions.
LDP Link Hello messages are encapsulated in UDP packets with the multicast
destination address 224.0.0.2. If an LSR receives an LDP Link Hello message
on an interface, the LSR connects to an LDP peer through this interface.
●
Extended discovery mechanism: discovers LSR peers not directly connected on
links.
LSRs periodically send LDP Targeted Hello messages to specified destination
IP addresses to establish remote LDP sessions through the extended discovery
mechanism.
LDP Targeted Hello messages are encapsulated in UDP packets with unicast
destination IP addresses. If an LSR receives LDP Targeted Hello messages, LDP
peers are connected to this LSR.
LDP Session Setup Process
Two LSRs exchange Hello messages to establish an LDP session.
Figure 4-1 shows the process of establishing an LDP session.
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Figure 4-1 Process of establishing an LDP session
LSR_2 (responder)
192.168.1.1/32
LSR_1 (initiator)
192.168.1.2/32
Step 1
Step 2
Step 3
Step 4
Step 5
Send Hello messages.
LSR_1 initiates a TCP connection.
LSR_1 sends an Initialization message.
If LSR_2 accepts parameters in the Initialization
message, LSR_2 sends an Initialization
message and a Keepalive message to LSR_1.
If LSR_1 accepts the parameters in the
Initialization message sent from LSR_2, LSR_1
sends a Keepalive message to LSR_2.
The LDP session setup process is as follows:
1.
Two LSRs send Hello messages to each other.
Each Hello message contains the transport address (device IP address) used to
establish an LDP session.
2.
The LSR with a larger transport address initiates a TCP connection.
LSR_1 initiates a TCP connection and LSR_2 waits for the TCP connection
request, as shown in Figure 4-1.
3.
After the TCP connection is successfully established, LSR_1 sends an
Initialization message to negotiate parameters with LSR_2 to establish the
LDP session.
These parameters include the LDP version, label distribution mode, Keepalive
timer value, maximum packet data unit (PDU) length, and label space.
4.
If LSR_2 accepts the parameters in the Initialization message, LSR_2 sends an
Initialization message and a Keepalive message to LSR_1.
If LSR_2 rejects the parameters in the Initialization message, LSR_2 sends a
Notification message to LSR_1 to stop the establishment process.
Parameters in the Initialization message include the LDP version, label
distribution mode, Keepalive timer value, maximum PDU length, and label
space.
5.
If LSR_1 accepts the parameters in the Initialization message, LSR_1 sends a
Keepalive message to LSR_2.
If LSR_1 rejects the parameters in the Initialization message, LSR_1 sends a
Notification message to LSR_2 to stop the establishment process.
After both LSR_1 and LSR_2 have accepted Keepalive messages from each other,
an LDP session is established between them.
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4.2.2.3 LDP LSP Setup
LDP peers send Label Request and Mapping messages to advertise FEC-to-label
mappings and establish LSPs based on mappings. Label distribution and
management depend on advertisement, distribution control, and retention modes.
Label Advertisement and Management
Label Advertisement Mode
An LSR distributes a label to a specified FEC and notifies an upstream LSR of this
label. This means the label is specified by a downstream LSR and distributed from
downstream to upstream.
Two label advertisement modes are available and label advertisement modes on
upstream and downstream LSRs must be the same, as shown in Table 4-1.
Table 4-1 Label advertisement mode
Label Advertisement
Mode
Definition
Description
Downstream Unsolicited
(DU) mode
An LSR distributes a
label for a specified FEC
without receiving a Label
Request message from
an upstream LSR.
As shown in Figure 4-2,
the downstream egress
node actively sends a
Label Mapping message
to the upstream transit
node to advertise the
label for the host route
192.168.1.1/32.
Downstream on Demand
(DoD) mode
An LSR distributes a
label for a specified FEC
only after receiving a
Label Request message
from an upstream LSR.
As shown in Figure 4-2,
the downstream egress
node sends a Label
Mapping message to the
upstream transit node to
advertise the label for
the host route
192.168.1.1/32 after
receiving a Label Request
message from the
ingress node.
When the DU mode is used, LDP distributes labels to all peers by default. Each node sends
Label Mapping messages to all peers without distinguishing upstream and downstream
nodes. If LSRs only distribute labels to upstream peers, they must identify their upstream
and downstream nodes based on routing information before sending Label Mapping
messages. Upstream nodes cannot send Label Mapping messages to their downstream
nodes. If upstream/downstream roles change because corresponding routes change, new
downstream nodes send Label Mapping messages to their upstream nodes. This slows
down network convergences.
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Figure 4-2 DU and DoD modes
DU
Distribute a label to
its upstream device
Distribute a label to
its upstream device
Ingress
Request a label from
DOD its downstream device
Transit
Request a label from its
downstream device
Send a label after the
request is received
192.168.1.1/32
Egress
Send a label after the
request is received
Label Distribution Control Mode
Label distribution control modes are used on the LSR during LSP establishment.
There are two label distribution control modes: Independent and Ordered.
●
Independent mode
A local LSR distributes a label bound to an FEC and informs its upstream LSR
without waiting for the label distributed by its downstream LSR.
●
Ordered mode
An LSR advertises mappings between a label and an FEC to its upstream LSR
only when the LSR is the outgoing node of the FEC or receives a Label
Mapping message from the next hop.
Table 4-2 describes the combination between the label distribution control mode
and label advertisement mode.
Table 4-2 Combination between the label distribution control mode and label
advertisement mode
Label Distribution
Control Mode
DU Mode
DoD Mode
Independent Mode
A transit LSR can assign
a label to the ingress
node without waiting for
the label assigned by the
egress node.
The directly-connected
ingress transit node that
sends a Label Request
message replies with a
label without waiting for
the label assigned by the
egress node.
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Label Distribution
Control Mode
DU Mode
DoD Mode
Ordered Mode
The LSR (the transit LSR
in Figure 4-2) must
receive a Label Mapping
message from the
downstream LSR (the
egress node in Figure
4-2). Then, the transit
LSR can distribute a label
to the ingress node in
the diagram.
The directly connected
transit node of the
ingress node that sends
the Label Request
message must receive a
Label Mapping message
from the downstream
(the egress node in the
diagram). Then, the
transit node can
distribute a label to the
ingress node in Figure
4-2.
Label Retention Mode
Label retention modes refer to modes used when LSRs receive label mappings not
immediately used. Label mappings received by LSRs may or may not come from
next hops. There are two types of label retention modes: Liberal and Conservative.
Table 4-3 compares the two label retention modes.
Table 4-3 Label retention mode
Label Retention Mode
Definition
Description
Liberal mode
Upon receiving a Label
Mapping message from
a neighbor LSR, the local
LSR retains the label
regardless of whether
the neighbor LSR is its
next hop.
When the next hop of an
LSR changes due to a
network topology
change, note that:
● In Liberal mode, LSRs
use previous labels
sent by non-next hops
to quickly reestablish
LSPs. This requires
more memory and
label space than
conservative modes.
● In Conservative mode,
LSRs only retain labels
sent by next hops.
This saves memory
and label space but
slows down the
reestablishment of
LSPs.
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Label Retention Mode
Definition
Description
Conservative mode
Upon receiving a Label
Mapping message from
a neighbor LSR, the local
LSR retains the label only
when the neighbor LSR
is its next hop.
Conservative and DoD
modes are used
together on LSRs with
limited label space.
The following mode combinations are supported:
●
(Default) DU label advertisement mode, ordered label distribution control
mode, and liberal label retention mode
●
DoD label advertisement mode, ordered label distribution control mode, and
conservative label retention mode
LDP LSP Setup Process
LSP setup is the process of mapping an FEC to a label and advertising the
mapping to neighboring LSRs. Figure 4-3 shows the LDP LSP setup process in DU
and Ordered modes.
Figure 4-3 LDP LSP setup process
FEC
3.3.3.3/32
In/Out Label
In/Out IF
NULL/1025
-/IF2
FEC
3.3.3.3/32
In/Out Label In/Out IF
1025/3
IF1/IF2
Loopback 0
1.1.1.1/32
Loopback 0
2.2.2.2/32
IF2
Ingress
FEC
3.3.3.3/32
In/Out Label
In/Out IF
3/NULL
IF1/-
IF1
FEC : 3.3.3.3
Loopback 0
3.3.3.3/32
IF2
Transit
Label: 1025
IF1
FEC : 3.3.3.3
Egress
Label: 3
LSP
Label mapping
LDP LSP setup consists of the following steps:
1.
By default, during route change, if an edge node (egress) finds a new host
route that does not belong to any existing FEC, the egress node creates an
FEC for the route.
2.
If the egress node has available labels, it distributes a label for the new FEC
and sends a Label Mapping message to the upstream node. This Label
Mapping message contains the distributed label and FEC.
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3.
After receiving the Label Mapping message, the upstream transit node checks
whether the sender (egress node) is the next hop of the FEC. If it is the next
hop, the transit node adds the label-to-FEC mapping in the Label Mapping
message to its label forwarding table, and sends the Label Mapping message
of the specified FEC to the upstream LSR (ingress).
4.
After receiving the Label Mapping message, the ingress node checks whether
the sender (transit node) is the next hop of the FEC. If it is the next hop, the
ingress node adds the label-to-FEC mapping in the Label Mapping message to
its label forwarding table. An LSP is established, and the packets of this FEC
can be forwarded based on labels.
This process establishes a common LDP LSP. A proxy egress establishes LSPs using
routes in which the next-hop addresses are not local addresses. If penultimate hop
popping (PHP) is enabled, an LSR at the penultimate hop is a specific proxy egress
along an LSP. A proxy egress is configured manually and applies to a network with
MPLS-incapable switches or helps load balance traffic based on Border Gateway
Protocol (BGP) routes.
Figure 4-4 shows the proxy egress of an LDP LSP.
Figure 4-4 Proxy egress
Proxy egress
Loopback 0
1.1.1.1/32
LSR_1
Loopback 0
2.2.2.2/32
Loopback 0
3.3.3.3/32
Loopback 0
4.4.4.4/32
LSR_2
LSR_3
LSR_4
MPLS domain
IP domain
In Figure 4-4, LSR_1, LSR_2, and LSR_3 are in an MPLS domain. LSR_4 is not
enabled with or does not support MPLS LDP. If a policy is configured to use all IGP
routes to establish LDP LSPs, LSR_3 functions as a proxy egress and becomes the
penultimate hop of the routes. This allows LSR_1, LSR_2, and LSR_3 to establish
LDP LSPs to LSR_4.
4.2.3 Coexistent Local and Remote LDP Session
When a local node establishes both local and remote LDP adjacencies with the
same LDP peer, local and remote LDP sessions coexist.
Figure 4-5 shows a coexistent local and remote LDP session between two nodes.
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Figure 4-5 Coexistent local and remote LDP session
Remote adjacency
P
CE_1
PE_1
Local
PE_2
adjacency
CE_2
In Figure 4-5, when the local LDP adjacency is deleted due to a failure in the link
to which the adjacency is connected, the peer type may change without affecting
its presence or status. (The peer type is determined by the adjacency type, which
can be local, remote, and coexistent local and remote.) If the link becomes faulty
or is recovering from a fault, the peer type and corresponding session type may
change. The session however stays Up and is not deleted or set to Down.
A typical application of coexistent local and remote LDP session is Layer 2 virtual
private network (L2VPN). In Figure 4-5, L2VPN services are transmitted between
PE_1 and PE_2. When the direct link between PE_1 and PE_2 is disconnected and
then recovers, changes in the peer and session types are as follows:
1.
MPLS LDP is enabled on the directly connected PE_1 and PE_2, and a local
LDP session is set up between them. PE_1 and PE_2 are then configured as
the remote peer of each other, and a remote LDP session is set up between
them. PE_1 and PE_2 maintain both local and remote adjacencies. In this case,
a coexistent local and remote LDP session is set up between PE_1 and PE_2 to
transmit L2VPN messages.
2.
When the physical link between PE_1 and PE_2 goes Down, local LDP
adjacency goes Down. The route between PE_1 and PE_2 is reachable through
the P, which indicates that the remote LDP adjacency is still Up. The session
type changes to remote so that it can remain Up. The L2VPN is uninformed of
the session type change and does not delete the session. This avoids the
neighbor disconnection and recovery process and therefore reduces the
service interruption time.
3.
When the physical link between PE_1 and PE_2 recovers, local LDP adjacency
goes Up. The session type is restored to coexistent local and remote and
remains Up. Again, L2VPN is uninformed of the session type change and does
not delete the session. This reduces service interruption time.
4.2.4 LDP Security Mechanisms
MPLS provides three security mechanisms to ensure the security of LDP packets:
LDP message digest algorithm 5 (MD5), LDP Keychain authentication, and LDP
Generalized TTL Security Mechanism (GTSM).
LDP Keychain is more secure than LDP MD5 authentication, and only one of these
mechanisms is used for an LDP peer. LDP GTSM protects devices against attacks of
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invalid LDP packets and can be used with LDP MD5 authentication or LDP
Keychain.
MD5 Authentication
MD5 authentication is a standard digest algorithm defined in RFC 1321. MD5
calculates message digests to prevent message spoofing. MD5 message digests
are unique results calculated by irreversible character string conversions. If
messages are modified during transmission, different digests are generated. After
messages arrive at receivers, receivers determine whether these messages have
been modified by comparing received digests with pre-calculated digests.
MD5 generates unique digests for information segments to prevent LDP packets
from being modified. This authentication method is stricter than the common
checksum verification of TCP.
MD5 authentication is as follows:
1.
Before an LDP session message is sent over a TCP connection, the sender pads
the TCP header with a unique digest. The digest is calculated using the MD5
algorithm based on the TCP header, LDP session message, and configured
password.
2.
Upon receiving the TCP packet, the receiver obtains the TCP header, digest,
and LDP session message, and uses MD5 to calculate a digest based on the
received TCP header, LDP session message, and locally stored password. The
receiver compares the calculated digest with the received one to check
whether the packet has been modified.
Passwords are set in either cipher text or plain text. Plain-text passwords are saved
directly in configuration files. Cipher-text passwords are saved in configuration
files after being encrypted using special algorithms. Character strings, entered by
users are, however, used to calculate digests, regardless of whether passwords are
set in plain text or cipher text. Cipher-text passwords, in particular, do not
participate in MD5 calculation. As devices from different vendors use proprietary
password encryption algorithms, LDP MD5 authentication shields differences of
password encryption algorithms used on different devices.
Keychain Authentication
Compared with LDP MD5, LDP Keychain is an enhanced encryption algorithm that
calculates message digests for the same LDP messages to prevent messages from
being modified.
LDP Keychain allows users to define password groups as password strings.
Encryption/Decryption algorithms and validity periods are defined for passwords.
Devices select valid passwords based on configurations, encrypt packets before
sending them, and decrypt packets upon receiving using encryption or decryption
algorithms, (such as MD5 and SHA-1) matching selected passwords. In addition,
devices use new passwords after previous passwords expire, minimizing risks of
cracking passwords.
Keychain authentication passwords, encryption and decryption algorithms, and
password validity periods are configured independently. Keychain configuration
nodes require at least one password as well as encryption and decryption
algorithms.
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LDP GTSM
GTSM protects services by checking whether time-to-live (TTL) values in IP
headers are within pre-defined ranges. The prerequisites for using GTSM include:
●
The TTL of normal packets between devices is determined.
●
Changing TTL values is difficult.
LDP GTSM refers to implementing GTSM over LDP.
To protect devices against attacks, GTSM verifies TTL in packets. LDP GTSM is
applied to LDP packets between neighbors or adjacent devices (based on a fixed
number of hops). TTL ranges are preset on devices for packets from other devices.
With LDP GTSM enabled, if LDP packet TTLs received by LDP-enabled devices are
out of TTL ranges, packets are considered invalid and are discarded. LDP GTSM
protects upper-layer protocols.
4.2.5 LDP Extensions for Inter-Area LSPs
LDP extensions for inter-area LSPs enable LDP to search for routes according to
the longest match rule and use summarized routes to establish LDP LSPs spanning
multiple IGP areas.
Background
On a large-scale network, multiple IGP areas are often configured for flexible
network deployment and fast route convergence. To reduce the number of routes
and conserve resources, area border routers (ABRs) summarize the routes in their
areas and advertise the summarized routes to neighboring IGP areas. However,
LDP follows the exact match rule when establishing LSPs. LDP searches for the
route exactly matching a forwarding equivalence class (FEC) in the received Label
Mapping message. If only summarized routes are available, LDP supports only
liberal LSPs and cannot set up inter-area LSPs. LDP extensions are available to
help set up inter-area LDP LSPs.
A liberal LSP is an LSP that has been assigned labels but fails to be established.
Implementation
The network shown in Figure 4-6 has two IGP areas, Area 10 and Area 20. LSR_2
at the border of Area 10 has two host routes to LSR_3 and LSR_4. To reduce the
resources consumed by routes, LSR_2 can run IS-IS to summarize the two routes
to one route 1.3.0.0/24 and advertise this route to Area 20.
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Figure 4-6 Networking topology for LDP extensions for inter-area LSPs
Loopback0
1.3.0.1/32
Loopback0
1.2.0.1/32
Loopback0
1.1.0.1/32
LSR_3
IS-IS
Area10
LSR_1
LSR_2
IS-IS
Area20
Loopback0
1.3.0.2/32
LSR_4
When establishing an LSP, LDP searches the routing table for the route that
exactly matches the FEC in the received Label Mapping message. In Figure 4-6,
LSR_1 has only a summarized route (1.3.0.0/24) but not 32-bit host routes in its
routing table. Table 4-4 lists the route of LSR_1 and routes carried in the FEC.
Table 4-4 Route of LSR_1 and routes carried in the FEC
Route of LSR_1
FEC
1.3.0.0/24
1.3.0.1/32
1.3.0.2/32
If only summarized routes are available, LDP supports only liberal LSPs and cannot
set up inter-area LDP LSPs. In this situation, tunnels cannot be set up on the
backbone network.
To set up an LSP, LSR_1 must follow the longest match rule to find the route.
There is a summarized route 1.3.0.0/24 in the routing table of LSR_1. When LSR_1
receives a Label Mapping message (for example, a message carrying FEC
1.3.0.1/32) from Area 10, LSR_1 finds the summarized route 1.3.0.0/24 according
to the longest match rule. Then LSR_1 applies the outbound interface and next
hop of the summarized route to the route 1.3.0.1/32. An inter-area LDP LSP is
established.
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4.2.6 LDP Reliability
4.2.6.1 Overview of LDP Reliability
Reliability measures are used to ensure the reliability of LSPs. LSPs are paths
established through LDP.
LDP LSP reliability technologies are necessary for the following reasons:
●
If a node or link on a working LDP LSP fails, reliability technologies are used
to establish a backup LDP LSP and switch traffic to the backup LDP LSP, while
minimizing packet losses in the process.
●
If a node on a working LDP LSP encounters a control plane failure but the
forwarding plane is still working, reliability technologies ensure traffic
forwarding during fault recovery on the control plane.
MPLS provides multiple reliability technologies to ensure the high reliability of key
services transmitted over LDP LSP. The following table describes the LDP reliability
technologies.
Table 4-5 LDP reliability technologies
Reliability
Technology
Description
Function
Fault
detection
Rapidly detects faults on LDP LSPs of
an MPLS network and triggers
protection switching.
● 4.2.6.2 BFD for
LDP LSP
Traffic
protection
Ensures traffic is switched to the
backup LDP LSP and minimizes packet
loss when the working LDP LSP fails.
● 4.2.6.3
Synchronization
Between LDP and
IGP
Ensures nonstop forwarding on the
forwarding plane when the control
plane fails on a node.
● 4.2.6.5 LDP GR
4.2.6.2 BFD for LDP LSP
Bidirectional Forwarding Detection (BFD) improves network reliability by quickly
detecting LDP LSP faults and triggering traffic switchover upon LDP LSP faults.
Background
If a node or link along a working LDP LSP fails, traffic is switched to the backup
LSP. The fault detection mechanism of LDP is slow so traffic switching between
primary and backup LDP LSPs takes a relatively long time, causing traffic loss.
Figure 4-7 shows fault detection through the exchange of Hello messages.
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Figure 4-7 Fault detection through the exchange of Hello messages
LSR_3
LSR_1
LSR_2
LSR_5
LSR_6
Primary LSP
Backup LSP
LSR_4
Hello message
In Figure 4-7, an LSR periodically sends Hello messages to its neighboring LSRs to
advertise its network existence and maintain adjacencies. An LSR creates a Hello
timer for each neighbor to maintain an adjacency. Each time the LSR receives a
Hello message, the LSR resets the Hello timer. If the Hello timer expires before the
LSR receives a new Hello message, the LSR considers the adjacency terminated.
Exchange of Hello messages cannot detect link faults quickly, especially when a
Layer 2 device is deployed between LSRs.
BFD for LDP LSP quickly detects faults on an LDP LSP and triggers a traffic
switchover upon LDP LSP failures, minimizing packet losses and improving
network reliability.
Implementation
BFD for LDP LSP rapidly detects faults on LDP LSPs and notifies the forwarding
plane of the fault to ensure fast traffic switchover.
The implementation process is as follows:
1.
A BFD session is bound to an LSP established between ingress and egress
nodes.
2.
A BFD packet is sent from the ingress node to the egress node along an LSP.
3.
The egress node responds to the BFD packet, allowing the ingress node to
quickly detect the LSP status.
4.
After BFD detects an LSP failure, it notifies the forwarding plane.
5.
The forwarding plane switches traffic to the backup LSP.
The following figure shows quick fault detection using BFD for LDP LSP.
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Figure 4-8 BFD for LDP LSP
LSR_3
LSR_1
LSR_2
LSR_5
LSR_4
LSR_6
Primary LSP
Backup LSP
BFD session
4.2.6.3 Synchronization Between LDP and IGP
Synchronization between LDP and IGP ensures consistent IGP and LDP traffic by
suppressing IGP route advertisement. This minimizes packet loss and improves
network reliability.
Background
Because LDP convergence is slower than IGP route convergence, the following
problems occur on an MPLS network where primary and backup links exist:
●
When a primary link fails, both the IGP route and LSP are switched to backup
link. After the primary link recovers, the IGP route is switched to the original
primary link before LDP convergence completes. As a result, traffic is dropped
during attempts to use the unreachable LSP.
●
When an IGP route of the primary link is reachable and an LDP session
between nodes on the primary link fails, traffic is directed using the IGP route
of the primary link, while the LSP over the primary link is torn down. Since a
preferred IGP route of the backup link is unavailable, an LSP over the backup
link cannot be established, causing traffic loss.
●
When the primary/backup switchover occurs on a node, the LDP session is
established after IGP GR completion. IGP advertises the maximum cost of the
link, causing route flapping.
Synchronization between LDP and IGP helps prevent traffic loss caused by these
problems.
Related Concepts
Synchronization between LDP and IGP involves three timers:
●
Hold-down timer: controls the period of time before establishing IGP neighbor
relationships.
●
Hold-max-cost timer: controls the interval for advertising the maximum link
cost on an interface.
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4 MPLS LDP Configuration
Delay timer: controls the period of time before LSP establishment.
Implementation
●
Figure 4-9 shows the implementation of switching between primary/backup
links.
Figure 4-9 Switching between primary/backup links
LSR_3
LSR_1
LSR_2
LSR_5
LSR_4
LSR_6
Primary LSP
Backup LSP
Link fault
LSP fault
Synchronization between LDP and IGP is implemented as follows:
–
–
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The primary link recovers from a physical fault.
i.
The faulty link between LSR_2 and LSR_3 recovers.
ii.
An LDP session is set up between LSR_2 and LSR_3. IGP starts the
Hold-down timer to suppress establishment of the neighbor
relationship.
iii.
Traffic keeps traveling through the backup LSP.
iv.
After the link fault is rectified, LSR2 and LSR3 discover each other as
LDP peers and reestablish an LDP session (along the path LSR2 ->
LSR4 -> LSR5 -> LSR3). LSR2 and LSR3 send a Label Mapping
message to each other to establish an LSP and instruct IGP to start
synchronization.
v.
IGP establishes a neighbor relationship and switches traffic back to
the primary link. The LSP is reestablished and its route converges on
the primary link.
IGP on the primary link is normal and the LDP session is Down.
i.
An LDP session between nodes along the primary link becomes
Down.
ii.
LDP notifies the primary link of the session fault. IGP starts the Holdmax-cost timer and advertises the maximum cost on the primary
link.
iii.
The IGP route of the backup link becomes reachable.
iv.
An LSP is established over the backup link and the LDP module on
LSR_2 delivers forwarding entries.
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The Hold-max-cost timer is configured to always advertise the maximum
cost of the primary link. This allows traffic to continue through the
backup link before the LDP session over the primary link is reestablished.
●
Figure 4-10 shows synchronization between LDP and IGP upon a primary/
backup switchover on a node.
Figure 4-10 Primary/backup switchover on a node
LSR_3
GR Helper
LSR_1
LSR_2
LSR_5
GR Restarter
LSR_6
Primary LSP
Backup LSP
LSR_4
Active/Standby switchover
Synchronization between LDP and IGP is implemented as follows:
a.
An IGP on the GR Restarter advertises the actual cost of the primary link
and starts the GR Delay timer. The GR Restarter does not end the GR
process before the GR Delay timer expires. An LDP session is established
during this period.
b.
Before the GR Delay timer expires, the GR Helper retains the original IGP
route and the LSP. If the LDP session goes Down, LDP does not notify the
IGP link that the session is Down. In this case, IGP still advertises the
actual link cost, ensuring the IGP route is not switched to the backup link.
If the GR Delay timer expires, GR is complete. If the LDP session is not
established, IGP starts the Hold-max-cost timer and advertises the
maximum cost of the primary link, so the IGP route is switched to the
backup link.
c.
If the LDP session is established or the Hold-max-cost timer expires, IGP
resumes the actual link cost of the interface and then switches the IGP
route back to the primary link.
4.2.6.4 LDP FRR
LDP fast reroute (FRR) provides link backup on an MPLS network. When the
primary LSP fails, traffic is quickly switched to the backup LSP, minimizing traffic
loss.
Background
On an MPLS network, when the primary link fails, IP FRR ensures fast IGP route
convergence and switches traffic to the backup link. However, a new LSP needs to
be established, which causes traffic loss. If the LSP fails (for some reason other
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than a primary link failure), traffic is restored until a new LSP is established,
causing traffic interruption for a long time. LDP FRR is used on an MPLS network
to address these issues.
LDP FRR, using the liberal label retention mode of LDP, obtains a liberal label,
assigns a forwarding entry to the label, and delivers the forwarding entry to the
forwarding plane as the backup forwarding entry for the primary LSP. When the
interface goes Down (detected by the interface itself or by BFD) or the primary
LSP fails (detected by BFD), traffic is quickly switched to the backup LSP.
Concepts
LDP FRR protects LSPs in two modes:
●
Manual LDP FRR: The outbound interface and next hop of the backup LSP
must be specified using a command. When the source of the liberal label
matches the outbound interface and next hop, a backup LSP can be
established and its forwarding entry can be delivered.
●
Auto LDP FRR: This automatic approach depends on IP FRR. A backup LSP can
be established and its forwarding entry can be delivered only when the source
of the liberal label matches the backup route. That is, the liberal label is
obtained from the outbound interface and next hop of the backup route, the
backup LSP triggering conditions are met, and there is no backup LSP
manually configured based on the backup route. By default, LDP LSP setup is
triggered by a 32-bit backup route.
When both Manual LDP FRR and Auto LDP FRR meet the establishment
conditions, Manual LDP FRR backup LSP is established preferentially.
Implementation
In liberal label retention mode, an LSR can receive a Label Mapping message of an
FEC from any neighboring LSR. However, only the Label Mapping message sent by
the next hop of the FEC can be used to generate a label forwarding table for LSP
setup. In contrast, LDP FRR can generate an LSP as the backup of the primary LSP
based on Label Mapping messages that are not from the next hop of the FEC.
Auto LDP FRR establishes a forwarding entry for the backup LSP and adds the
forwarding entry to the forwarding table. If the primary LSP fails, traffic is
switched to the backup LSP quickly to minimize traffic loss.
Figure 4-11 LDP FRR - triangle topology
LSR_3
Backup LSP
LSR_1
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Primary LSP
LSR_2
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In Figure 4-11, the optimal route from LSR_1 to LSR_2 is LSR_1-LSR_2. A
suboptimal route is LSR_1-LSR_3-LSR_2. After receiving a label from LSR_3, LSR_1
compares the label with the route from LSR_1 to LSR_2. Because LSR_3 is not the
next hop of the route from LSR_1 to LSR_2, LSR_1 stores the label as a liberal
label. If a route is available for the source of the liberal label, LSR_1 assigns a
forwarding entry to the liberal label as the backup forwarding entry, and then
delivers this forwarding entry to the forwarding plane with the primary LSP. In this
way, the primary LSP is associated with the backup LSP.
LDP FRR is triggered when an interface failure is detected by the interface itself or
BFD, or a primary LSP failure is detected by BFD. After LDP FRR is complete, traffic
is switched to the backup LSP using the backup forwarding entry. Then the route is
converged from LSR_1-LSR_2 to LSR_1-LSR_3-LSR_2. An LSP is established on the
new path (the original backup LSP) and the original primary LSP is deleted. Traffic
is forwarded along the new LSP of LSR_1-LSR_3-LSR_2.
Usage Scenario
Figure 4-11 shows a typical application environment of LDP FRR. LDP FRR
functions well in a triangle topology but may not take effect in some situations in
a rectangle topology.
Figure 4-12 LDP FRR - rectangle topology
LSR_3
Primary LSP
LSR_4
Backup LSP
LSR_1
LSR_2
As shown in Figure 4-12, if the optimal route from LSR_1 to LSR_4 is LSR_1LSR_2-LSR_4 (with no other route for load balancing), LSR_3 receives a liberal
label from LSR_1 and is bound to LDP FRR. If the link between LSR_3 and LSR_4
fails, traffic is switched to the route of LSR_3-LSR_1-LSR_2-LSR_4. No loop occurs
in this situation.
However, if optional routes from LSR_1 to LSR_4 are available for load balancing
(LSR_1-LSR_2-LSR_4 and LSR_1-LSR_3-LSR_4), LSR_3 may not receive a liberal
label from LSR_1 because LSR_3 is a downstream node of LSR_1. Even if LSR_3
receives a liberal label and is configured with LDP FRR, traffic may still be
forwarded to LSR_3 after the traffic switching, leading to a loop. The loop exists
until the route from LSR_1 to LSR_4 is converged to LSR_1-LSR_2-LSR_4.
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4.2.6.5 LDP GR
LDP Graceful Restart (GR) ensures uninterrupted traffic transmission during a
protocol restart or a primary/backup switchover because the forwarding plane is
separated from the control plane.
Background
On an MPLS network, when the GR Restarter restarts a protocol or performs a
primary/backup switchover, label forwarding entries on the forwarding plane are
deleted, interrupting data forwarding.
LDP GR addresses this issue and therefore improves network reliability. During a
protocol restart or primary/backup switchover, LDP GR retains label forwarding
entries because the forwarding plane is separated from the control plane. The
switch still forwards packets based on the label forwarding entries, ensuring data
transmission. After the protocol restart or primary/backup switchover is complete,
the GR Restarter can restore to the original state with the help of the GR Helper.
Related Concepts
LDP GR is a high-reliability technology based on non-stop forwarding (NSF). The
GR process involves GR Restarter and GR Helper devices:
●
GR Restarter has GR capability.
●
GR Helper is a GR-capable neighbor of the GR Restarter.
LDP GR uses the following timers:
●
Forwarding State Holding timer: specifies the duration of the LDP GR process.
●
Reconnect timer: controls the time the GR Helper waits for LDP session
reestablishment. After a protocol restart or primary/backup switchover occurs
on the GR Restarter, the GR Helper detects the LDP session as Down. The GR
Helper then starts this timer to wait for the LDP session to be reestablished.
●
Recovery timer: controls the time the GR Helper waits for LSP recovery. After
the LDP session is reestablished, the GR Helper starts this timer to wait for the
LSP to recover.
Implementation
Figure 4-13 shows LDP GR implementation.
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Figure 4-13 LDP GR implementation
GR Restarter
GR Helper
Negotiate GR capability
Active/Standby
switchover or
protocol restart
Send an LDP Initialization message
Reestablish an LDP session
Forwarding
State Holding
timer
Exchange Label Mapping messages
Reconnect
timer
Recovery
timer
The implementation of LDP GR is as follows:
1.
An LDP session is set up between the GR Restarter and GR Helper. The GR
Restarter and GR Helper negotiate GR capabilities during LDP session setup.
2.
When restarting a protocol or performing a primary/backup switchover, the
GR Restarter starts the Forwarding State Holding timer, retains label
forwarding entries, and sends an LDP Initialization message to the GR Helper.
When the GR Helper detects that the LDP session with the GR Restarter is
Down, it retains label forwarding entries of the GR Restarter and starts the
Reconnect timer.
3.
After the protocol restart or primary/backup switchover, the GR Restarter
reestablishes an LDP session with the GR Helper. If an LDP session is not
reestablished before the Reconnect timer expires, the GR Helper deletes label
forwarding entries of the GR Restarter.
4.
After the GR Restarter reestablishes an LDP session with the GR Helper, the
GR Helper starts the Recovery timer. Before the Recovery timer expires, the GR
Restarter and GR Helper exchange Label Mapping messages over the LDP
session. The GR Restarter and GR Helper then restore forwarding entries with
each other's help. After the Recovery timer expires, the GR Helper deletes all
forwarding entries that have not been restored.
5.
After the Forwarding State Holding timer expires, the GR Restarter deletes
label forwarding entries and completes the implementation process.
4.3 Summary of MPLS LDP Configuration Tasks
After basic functions of MPLS LDP are configured, you can build an MPLS network
using LDP. To ensure network reliability and security, you need to perform other
configuration in addition to MPLS LDP.
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Table 4-6 lists MPLS LDP configuration tasks.
Table 4-6 MPLS LDP configuration tasks
Scenario
Description
Task
Configure basic
functions of
MPLS LDP
You can build an MPLS
network and establish LDP
LSPs only after basic functions
of MPLS LDP are configured.
4.6 Configuring Basic
Functions of MPLS LDP
Configure LDP
extensions for
inter-area LSPs
This function enables LDP to
search for routes according to
the longest match rule and to
establish multiple inter-area
LDP LSPs based on the
summarized route.
4.7 Configuring LDP
Extensions for Inter-Area
LSPs
Configure LDP
reliability
The following reliability
technologies can be used to
improve MPLS network
reliability:
4.8 Configuring Static BFD
to Detect an LDP LSP
● BFD for LDP LSPs: quickly
detects faults on an LDP
LSP and triggers a traffic
switchover upon an LDP
LSP failure, minimizing
packet loss.
4.10 Configuring
Synchronization Between
LDP and IGP
4.9 Configuring Dynamic
BFD for LDP LSPs
4.11 Configuring LDP FRR
4.12 Configuring LDP GR
● Synchronization between
LDP and IGP: solves the
traffic loss problem when
the primary LSP is faulty in
networking where there
are the primary and
backup LSPs.
● LDP fast reroute (LDP
FRR): provides link backup
on an MPLS network.
When the primary LSP
fails, traffic is quickly
switched to the backup
LSP, minimizing traffic loss.
● LDP GR: ensures
uninterrupted traffic
transmission when an
active/standby switchover
or a protocol restart occurs
on the neighboring device
(GR Restarter). LDP GR
helps GR Restarter to
restart.
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Scenario
Description
Task
Configure LDP
security
mechanisms
LDP security mechanisms
ensure security of LDP
messages.
4.13 Configuring LDP
Security Mechanisms
Configure nonlabeled public
network routes
to be iterated
to LSPs
After this configuration is
performed on access devices,
service data is forwarded to
the Internet through tunnels.
By dong this, core devices of
the carrier do not need to
learn many Internet routes,
saving the routing table
storage space and CPU
resources.
4.14 Configuring Nonlabeled Public Network
Routes to Be Iterated to
LSPs
4.4 Licensing Requirements and Limitations for MPLS
LDP
Involved Network Elements
Other network elements are not required.
License Requirements
MPLS LDP is a basic feature of a switch and is not under license control.
Version Requirements
Table 4-7 Products and versions supporting MPLS LDP
Produ
ct
Product Model
Software Version
S1700
S1720GFR
Not supported
S1720GW,
S1720GWR
Not supported
S1720GW-E,
S1720GWR-E
Not supported
S1720X, S1720XE
Not supported
Other S1700
models
Models that cannot be configured using
commands. For details about features and versions,
see S1700 Documentation Bookshelf.
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Produ
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Product Model
Software Version
S2700
S2700SI
Not supported
S2700EI
Not supported
S2710SI
Not supported
S2720EI
Not supported
S2750EI
Not supported
S3700SI, S3700EI
Not supported
S3700HI
Not supported
S5700LI
Not supported
S5700S-LI
Not supported
S5710-C-LI
Not supported
S5710-X-LI
Not supported
S5700SI
Not supported
S5700EI
Not supported
S5710EI
V200R002C00, V200R003C00, V200R005(C00&C02)
S5720EI
V200R009C00, V200R010C00, V200R011C00,
V200R011C10
S5720LI, S5720SLI
Not supported
S5720SI, S5720SSI
Not supported
S5700HI
V200R001(C00&C01), V200R002C00,
V200R003C00, V200R005(C00SPC500&C01&C02)
S5710HI
V200R003C00, V200R005(C00&C02&C03)
S5720HI
V200R007C10, V200R009C00, V200R010C00,
V200R011C00, V200R011C10
S5730SI
Not supported
S5730S-EI
Not supported
S6720LI, S6720SLI
Not supported
S6720SI, S6720SSI
Not supported
S6700EI
V200R005(C00&C01&C02)
S3700
S5700
S6700
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Product Model
Software Version
S6720EI
V200R008C00, V200R009C00, V200R010C00,
V200R011C00, V200R011C10
S6720S-EI
V200R009C00, V200R010C00, V200R011C00,
V200R011C10
To know details about software mappings, see Hardware Query Tool.
Feature Limitations
●
In V200R003 and earlier versions, only VLANIF interfaces support MPLS LDP.
In V200R005 and later versions, only VLANIF interfaces and Layer 3 Ethernet
interfaces support MPLS LDP.
●
On the S5720EI switch, if hardware support for MPLS is displayed as NO in
the output of the display device capability command, the switch does not
support MPLS. In this case, you need to pay attention to the following points:
–
MPLS cannot be enabled on the S5720EI switch. If the switch has been
added to a stack, MPLS cannot be enabled on the stack.
–
The S5720EI switch cannot be added to a stack running MPLS.
4.5 Default Settings for MPLS LDP
Table 4-8 Default settings for MPLS LDP
Parameter
Default Setting
Global MPLS capability
Disabled
Global MPLS LDP capability
Disabled
Link-Hello send timer
5 seconds
Link-Hello hold timer
15 seconds
Target-Hello send timer
15 seconds
Target-Hello hold timer
45 seconds
Keepalive send timer
15 seconds
Keepalive hold timer
45 seconds
Exponential backoff timer
Initial value: 15 seconds; maximum
value: 120 seconds
Longest-match
Disabled
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Parameter
Default Setting
Global BFD capability
Disabled
Synchronization Between LDP and
Open Shortest Path First (OSPF)
Disabled
Synchronization Between LDP and
Intermediate System to Intermediate
System (IS-IS)
Disabled
LDP GR
Disabled
4.6 Configuring Basic Functions of MPLS LDP
You can build an MPLS network only after basic functions of MPLS LDP are
configured.
Pre-configuration Tasks
Before configuring basic functions of MPLS LDP, configure static routes or an IGP
to ensure that IP routes between LSRs are reachable.
When Routing Information Protocol version 1 (RIP-1) is used, you need to enable LDP to
search for routes to establish LSPs according to the longest match rule. For details, see 4.7
Configuring LDP Extensions for Inter-Area LSPs.
Configuration Procedure
Configure basic functions of MPLS LDP according to the following sequence.
4.6.1 Configuring the LSR ID
Context
An LSR ID identifies an LSR on a network. An LSR does not have the default LSR
ID, and you must configure an LSR ID for it. To enhance network reliability, you
are advised to use the IP address of a loopback interface on the LSR as the LSR ID.
Perform the following steps on each node in an MPLS domain.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls lsr-id lsr-id
The LSR ID of the local node is configured.
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By default, no LSR ID is set.
----End
Follow-up Procedure
Before changing the configured LSP ID, run the undo mpls command in the
system view.
NOTICE
Running the undo mpls command to delete all MPLS configurations will interrupt
MPLS services, so plan the LSR ID of each LSP uniformly to prevent LSR ID change.
4.6.2 Enabling Global MPLS
Context
You can perform other MPLS configurations only after enabling global MPLS.
Perform the following steps on each node in an MPLS domain.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
MPLS is enabled globally and the MPLS view is displayed.
By default, no node is enabled with MPLS.
----End
4.6.3 Enabling Global MPLS LDP
Context
You can perform other MPLS LDP configurations only after enabling global MPLS
LDP.
Perform the following steps on each node in an MPLS domain.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls ldp
MPLS LDP is enabled globally and the MPLS LDP view is displayed.
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By default, LDP is not enabled globally.
Step 3 (Optional) Run lsr-id lsr-id
The LSR ID is set for an LDP instance.
By default, the LSR ID of the LDP instance is the LSR ID of the local node. It is
recommended that the default value be used.
In certain networking where VPN instances are used, such as BGP/MPLS IP VPN
networking, if the VPN address and the LSR ID overlap, you need to configure LSR
IDs for LDP instances to ensure that TCP connections can be correctly set up.
----End
4.6.4 Configuring LDP Sessions
Context
The MPLS LDP session is classified into local LDP sessions and remote LDP
sessions. You can choose one of the following configurations according to your
requirements:
●
Configuring a local LDP session
In most cases, you need to configure a local LDP session when deploying
MPLS LDP services.
●
Configuring a remote LDP session
In most cases, remote LDP sessions are not established between adjacent
LSRs. A remote LDP session is used for configuring a VLL or VPLS in Martini
mode.
A local LDP session and a remote LDP session can coexist. That is, two LSRs can
establish a local LDP session and a remote LDP session simultaneously. In this
case, configurations of the local and remote LDP sessions at both ends must be
the same.
Procedure
●
Configuring a local LDP session
Perform the following steps on two directly connected LSRs.
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The view of the interface on which the LDP session is to be set up is
displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
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Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run mpls
MPLS is enabled on the interface.
By default, no interface is enabled with MPLS.
e.
Run mpls ldp
MPLS LDP is enabled on the interface.
By default, no interface is enabled with LDP.
●
Configuring a remote MPLS LDP session
Perform the following steps on the LSRs on both ends of a remote LDP
session.
a.
Run system-view
The system view is displayed.
b.
Run mpls ldp remote-peer remote-peer-name
The remote peer is created and the remote peer view is displayed.
c.
Run remote-ip ip-address
The IP address of the remote MPLS LDP peer is configured.
By default, the IP address of the remote LDP peer is not configured.
This IP address must be the LSR ID of the remote MPLS LDP peer. If the
LSR IDs of the LDP instance and the local node are different, use the LSR
ID of the LDP instance.
NOTICE
● Modifying or deleting the IP address of a remote peer leads to
deletion of the remote LDP session and MPLS service interruption.
● After the IP address of the remote peer is configured using the
remote-ip ip-address command, the value of ip-address cannot be
used as the IP address of the local interface. Otherwise, the remote
session will be interrupted, causing MPLS service interruption.
----End
4.6.5 (Optional) Configuring an LDP Transport Address
Context
LDP sessions are established based on TCP connections. Before two LSRs establish
an LDP session, they need to check the LDP transport address of each other, and
then establish a TCP connection.
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Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface interface-type interface-number
The view of the interface on which the LDP session is to be set up is displayed.
Step 3 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 4 Run mpls ldp transport-address { interface-type interface-number | interface }
An LDP transport address is specified.
The default transport address for a node on a public network is the LSR ID of the
node, and the default transport address for a node on a private network is the
primary IP address of an interface on the node.
If LDP sessions are to be established over multiple links connecting two LSRs, LDPenabled interfaces on either LSR must use the default transport address or the
same transport address. If multiple transport addresses are configured on an LSR,
only one transport address can be used to establish only one LDP session.
NOTICE
Changing an LDP transport address interrupts an LDP session. Exercise caution
when running this command.
----End
4.6.6 (Optional) Configuring Timers for LDP Session
Context
Table 4-9 describes the timers for an LDP session.
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Table 4-9 Timers for an LDP session
LDP Timer
Description
Suggestion
Hello send
timer:
Used to send Hello
messages periodically to
notify a peer LSR of the
local LSR's presence and
establish a Hello adjacency.
On an unstable network,
decrease the value of a Hello
send timer, speeding up network
fault detection.
Used to exchange Hello
messages periodically
between two LDP peers to
maintain the Hello
adjacency. If no Hello
message is received after
the Hello hold timer
expires, the Hello adjacency
is torn down.
On a network with unstable links
or a large number of packets,
increase the value of the Hello
hold timer, preventing the LDP
session from being torn down
and set up frequently.
Keepalive
send timer
Used to send Keepalive
messages periodically,
maintaining the LDP
sessions.
On an unstable network, set a
smaller value for a Keepalive
send timer, speeding up network
fault detection.
Keepalive
hold timer
Used to send LDP PDUs
over an LDP session,
maintaining the LDP
session. If no LDP PDU is
received after the Keepalive
hold timer expires, the TCP
connection is closed and
the LDP session is
terminated.
On a network with unstable
links, increase the value of the
Keepalive hold timer, preventing
the LDP session from flapping.
● Link-Hello
send timer
(for only
local LDP
sessions)
● TargetHello send
timer (for
only
remote
LDP
sessions)
Hello hold
timer:
● Link-Hello
hold timer
(for only
local LDP
sessions)
● TargetHello hold
timer (for
only
remote
LDP
sessions)
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LDP Timer
Description
Suggestion
Exponential
backoff timer
Started by an LSR that plays
an active role after an LDP
Initialization message sent
by the LSR to another LSR
that plays a passive role
fails to be processed or
parameters carried in the
message are rejected. The
LSR that plays the active
role periodically resends an
LDP Initialization message
to initiate an LDP session
before the Exponential
backoff timer expires.
● When a device is upgraded,
prolong the period for the
active role to retry setting up
a session. In this case, you can
set larger initial and
maximum values for the
Exponential backoff timer.
● When a device that bears
services tends to alternate
between Up and Down,
shorten the period for the
active role to retry setting up
a session. In this case, you can
set smaller initial and
maximum values for the
Exponential backoff timer.
When local and remote LDP sessions coexist, the timeout interval of the Keepalive hold
timer of the local and remote LDP sessions must be the same.
Procedure
●
Configuring timers for a local LDP session
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The view of an interface on which an LDP session is to be established is
displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run mpls ldp timer hello-send interval
A link Hello send timer is configured.
The default value of a link Hello send timer is one third of the value of a
link Hello hold timer.
Effective value of a link Hello send timer = Min {Configured value of the
link Hello send timer, one third of the value of the link Hello hold timer}
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4 MPLS LDP Configuration
Run mpls ldp timer hello-hold interval
A link Hello hold timer is configured.
The default value of a link Hello hold timer is 15, in seconds.
The smaller value between two configured link Hello hold timers on both
ends of the LDP session takes effect.
f.
Run mpls ldp timer keepalive-send interval
A Keepalive send timer is configured.
The default value of a Keepalive send timer is one third of the value of
the Keepalive hold timer.
Effective value of a Keepalive send timer = Min { Configured value of the
Keepalive send timer, one third of the value of the Keepalive hold timer }
If more than one LDP-enabled links connect two LSRs, the values of
Keepalive send timers for all links must be the same. Otherwise, LDP
sessions become unstable or fail to be set up.
If there is only one link between two LSRs and both local and remote
sessions are configured, the local and remote sessions must have the
same Keepalive send timer value. Otherwise, LDP sessions become
unstable or fail to be set up.
g.
Run mpls ldp timer keepalive-hold interval
A Keepalive hold timer is configured.
The default value of a Keepalive hold timer is 45, in seconds.
The smaller value between two configured Keepalive hold timers on both
ends of the LDP session takes effect.
If more than one LDP-enabled links connect two LSRs, the values of
Keepalive hold timers for all links must be the same. Otherwise, LDP
sessions become unstable or fail to be set up.
If there is only one link between two LSRs and both local and remote
sessions are configured, the local and remote sessions must have the
same Keepalive hold timer value. Otherwise, LDP sessions become
unstable or fail to be set up.
NOTICE
Changing the Keepalive hold timer value in an instance will interrupt the
MPLS service in the instance because the LDP session must be
reestablished.
h.
Configure an Exponential backoff timer.
i.
Run quit
The system view is displayed.
ii.
Run mpls ldp
The MPLS LDP view is displayed.
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Run backoff timer init max
An Exponential backoff timer is configured.
By default, the initial value is 15 and the maximum value is 120, in
seconds. Setting the initial value of the Exponential backoff timer to
be greater than or equal to 15s and the maximum value to be
greater than or equal to 120s is recommended.
●
Configuring timers for a remote LDP session
a.
Run system-view
The system view is displayed.
b.
Run mpls ldp remote-peer remote-peer-name
The remote MPLS LDP peer view is displayed.
c.
Run mpls ldp timer hello-send interval
The target Hello send timer is configured.
The default value of the target Hello send timer is one third of the value
of a target Hello hold timer that takes effect.
Effective value of a target Hello send timer = Min { Configured value of
the target Hello send timer, One third of the value of the target Hello
hold timer }
d.
Run mpls ldp timer hello-hold interval
The target Hello hold timer is configured.
The default value of the target Hello hold timer is 45, in seconds.
The smaller value between two configured target Hello hold timers on
both ends of the LDP session takes effect.
e.
Run mpls ldp timer keepalive-send interval
A Keepalive send timer is configured.
The default value of a Keepalive send timer is one third of the value of
the Keepalive hold timer.
Effective value of a Keepalive send timer = Min { Configured value of the
Keepalive send timer, one third of the value of the Keepalive hold timer }
If more than one LDP-enabled links connect two LSRs, the values of
Keepalive send timers for all links must be the same. Otherwise, LDP
sessions become unstable or fail to be set up.
If there is only one link between two LSRs and both local and remote
sessions are configured, the local and remote sessions must have the
same Keepalive send timer value. Otherwise, LDP sessions become
unstable or fail to be set up.
f.
Run mpls ldp timer keepalive-hold interval
A Keepalive hold timer is configured.
The default value of a Keepalive hold timer is 45, in seconds.
The smaller value between two configured Keepalive hold timers on both
ends of the LDP session takes effect.
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If more than one LDP-enabled links connect two LSRs, the values of
Keepalive hold timers for all links must be the same. Otherwise, LDP
sessions become unstable or fail to be set up.
If there is only one link between two LSRs and both local and remote
sessions are configured, the local and remote sessions must have the
same Keepalive hold timer value. Otherwise, LDP sessions become
unstable or fail to be set up.
NOTICE
Changing the Keepalive hold timer value in an instance may interrupt the
MPLS service in the instance because the LDP session must be
reestablished.
g.
Configure an Exponential backoff timer.
i.
Run quit
The system view is displayed.
ii.
Run mpls ldp
The MPLS LDP view is displayed.
iii.
Run backoff timer init max
An Exponential backoff timer is configured.
By default, the initial value is 15 and the maximum value is 120, in
seconds. Setting the initial value of the Exponential backoff timer to
be greater than or equal to 15s and the maximum value to be
greater than or equal to 120s is recommended.
----End
4.6.7 (Optional) Configuring the PHP Feature
Context
No label needs to be swapped on the egress node of an LSP. PHP can be
configured on the egress node to allow the LSR at the penultimate hop to pop out
the label from an MPLS packet and send the packet to the egress node. After
receiving the packet, the egress node directly forwards the packet through an IP
link or according to the next layer label. PHP helps reduce the burden on the
egress node.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run label advertise { explicit-null | implicit-null | non-null }
The label allocated to the LSR at the penultimate hop is configured.
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The egress node can allocate different labels to the PHP based on the parameter
setting.
●
implicit-null: default value, which indicates that PHP is supported. If this
parameter is configured, the egress node allocates an implicit null label with
the value of 3 to the LSR at the penultimate hop.
●
explicit-null: PHP is not supported. If this parameter is configured, the egress
node allocates an explicit null label with the value of 0 to the LSR at the
penultimate hop. The explicit-null parameter can be configured when MPLS
QoS attributes are used.
●
non-null: PHP is not supported. If this parameter is configured, the egress
allocates a common label with a value greater than or equal to 16 to the LSR
at the penultimate hop.
After the label advertise command is run to change the label distribution mode on the
egress node, the modification takes effect on new LSPs but not on existing LSPs. To enable
the modification to take effect on the existing LSPs, run the reset mpls ldp or lsp-trigger
command.
----End
4.6.8 (Optional) Configuring an LDP Label Advertisement
Mode
Context
By default, a downstream node sends Label Mapping messages to its upstream
node. When faults occur on the network, services can be fast switched to the
standby path, improving network reliability. Edge devices on the MPLS network
are low-end devices. To ensure network reliability, resources must be fully used.
You can configure the Downstream on Demand (DoD) mode to save system
resources. In DoD mode, the downstream LSR sends a Label Mapping message to
the upstream LSR only when the upstream LSR sends a Label Request message to
the downstream LSR.
NOTICE
● Modifying a configured label advertisement mode leads to the reestablishment
of an LDP session, resulting in MPLS service interruption.
● When the local and remote LDP sessions coexist, they must be configured with the
same label advertisement mode.
Procedure
●
Configuring an LDP label advertisement mode of local LDP session.
a.
Run system-view
The system view is displayed.
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b.
4 MPLS LDP Configuration
Run interface interface-type interface-number
The interface view is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run mpls ldp advertisement { dod | du }
A label advertisement mode is configured.
By default, the label advertisement mode is downstream unsolicited
(DU).
Inconsistency in label advertisement modes leads to failure in
establishing LDP LSPs between the two LDP peers over multiple links.
●
Configuring an LDP label advertisement mode of remote LDP session.
a.
Run system-view
The system view is displayed.
b.
Run mpls ldp remote-peer remote-peer-name
A remote MPLS LDP peer is created and the remote MPLS LDP peer view
is displayed.
c.
Run mpls ldp advertisement { dod | du }
A label advertisement mode is configured.
By default, the label advertisement mode is downstream unsolicited
(DU).
----End
4.6.9 (Optional) Configuring LDP to Automatically Trigger the
Request in DoD Mode
Context
On a large-scale network, the label advertisement mode is set to downstream on
demand (DoD) to reduce the workload of edge devices. Because edge devices
cannot learn the accurate route to each other, an LDP LSP cannot be set up even if
LDP extensions for inter-area LSPs are configured. You can configure LDP to
automatically trigger the request in DoD mode to request the Label Mapping
message from a specified downstream LSR or all LSRs for LDP LSP establishment.
Before configuring LDP to automatically trigger the request in DoD mode, perform
the following operations:
●
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●
Configure LDP extensions for inter-area LSPs according to 4.7 Configuring
LDP Extensions for Inter-Area LSPs.
●
Configure the DoD mode according to 4.6.8 (Optional) Configuring an LDP
Label Advertisement Mode.
●
Configure automatic triggering of requests for Label Mapping messages in
DoD mode from all downstream remote LDP peers.
Procedure
a.
Run system-view
The system view is displayed.
b.
Run mpls ldp
The MPLS LDP view is displayed.
c.
Run remote-peer auto-dod-request
LDP is configured to automatically trigger requests for Label Mapping
messages in DoD mode from all downstream remote LDP peers.
By default, the device does not automatically trigger requests for Label
Mapping messages in DoD mode from all downstream remote LDP peers.
●
Configure automatic triggering of a request for a Label Mapping message in
DoD mode from a downstream remote LDP peer with a specified LSR ID.
a.
Run system-view
The system view is displayed.
b.
Run mpls ldp remote-peer remote-peer-name
A remote MPLS LDP peer is created and the remote MPLS LDP peer view
is displayed.
c.
Run remote-ip auto-dod-request [ block ]
LDP is configured to automatically trigger a request for a Label Mapping
message in DoD mode from a downstream remote LDP peer with a
specified LSR ID.
By default, the configuration of the remote-peer auto-dod-request
command is inherited.
If the remote-peer auto-dod-request command is enabled in the system
view, you can specify block to disable automatic triggering of a request
for a Label Mapping message in DoD mode from a downstream remote
LDP peer of a specified LSR ID.
----End
4.6.10 (Optional) Configuring LDP Loop Detection
Context
The device does not support LDP loop detection. If the neighbor of a node
supports loop detection and requires the same loop detection function on both
ends of an LDP session, configure LDP loop detection on the local node to ensure
the establishment of an LDP session.
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Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls ldp
The MPLS LDP view is displayed.
Step 3 Run loop-detect
The device is enabled to advertise the loop detection capability during
initialization of LDP sessions.
By default, a device does not advertise loop detection capability during
initialization of LDP sessions.
Step 4 (Optional) Run path-vectors integer
The maximum value of a path vector is specified.
By default, a maximum of 32 hops of the path vector are used for LDP loop
detection.
A path vector is carried in a Mapping message to record the addresses of nodes
that an LDP LSP has passed. By setting the maximum hops that a path vector can
record, you can adjust the sensitivity of LDP loop detection. If the maximum hops
of a path vector is n, the egress LSP triggered by local routes detects a loop after n
+ 1 hops, and the egress LSP triggered by non-local routes detects a loop after n
hops.
----End
4.6.11 (Optional) Configuring MPLS MTU
Context
The size of the maximum transmission unit (MTU) determines the maximum
number of bytes that can be transmitted by the sender at a time. If the MTU
exceeds the maximum number of bytes supported by the receiver or a transit
device, packets are fragmented or even discarded, which increases the network
transmission load. In this manner, devices have to calculate the MTU before the
communication to ensure that sent packets reach the receiver successfully.
LDP MTU = Min {All MTUs advertised by all downstream devices, MTU of the local
outbound interface}
A downstream LSR uses the preceding formula to calculate an MTU, adds it to the
MTU TLV in a Label Mapping message, and sends the Label Mapping message to
the upstream device. If an MTU value changes (such as when the local outbound
interface or its configuration is changed), an LSR recalculates an MTU and sends a
Label Mapping message carrying the new MTU to its upstream LSR. The
relationships between the MPLS MTU and the interface MTU are as follows:
●
If an interface MTU but not an MPLS MTU is configured on an interface, the
interface MTU is used.
●
If both an MPLS MTU and an interface MTU are configured on an interface,
the smaller value between the MPLS MTU and the interface MTU is used.
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4 MPLS LDP Configuration
MPLS determines the size of MPLS packets on the ingress node according to the
LDP MTU to prevent the transit node from forwarding large-sized MPLS packets.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls ldp
The MPLS LDP view is displayed.
Step 3 Run the following commands as required.
●
Run undo mtu-signalling
The LSR is disabled from sending Label Mapping messages carrying MTU
TLVs.
By default, the switch with MPLS LDP globally enabled sends Label Mapping
messages carrying the MTU TLV, in compliance with draft-ietf-mpls-ldp-mtuextensions.
If a non-Huawei device does not support the MTU TLV, to implement
interworking, configure the device not to encapsulate the MTU TLV in Label
Mapping messages. If the LSR is disabled from sending the MTU TLV, the
configured MPLS MTU does not take effect.
●
Run mtu-signalling apply-tlv
The LSR is configured to send Label Mapping messages carrying MTU TLVs
that comply with RFC 3988.
By default, the switch with MPLS LDP globally enabled sends Label Mapping
messages carrying the MTU TLV, in compliance with draft-ietf-mpls-ldp-mtuextensions.
If a non-Huawei device supports the MTU TLV, to implement interworking,
configure the device to send Label Mapping messages carrying MTU TLVs that
comply with RFC 3988. Otherwise, the configured MPLS MTU may not take
effect.
NOTICE
Enabling or disabling the function to send an MTU TLV leads the reestablishment
of existing LDP sessions, resulting in MPLS service interruption.
Step 4 Run quit
The system view is displayed.
Step 5 Run interface interface-type interface-number
The view of an MPLS-enabled interface is displayed.
Step 6 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
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Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 7 Run mpls mtu mtu
An MPLS MTU is configured on the interface.
By default, the MTU of MPLS packets is equal to the interface MTU.
----End
4.6.12 (Optional) Configuring the MPLS TTL Processing Mode
Context
MPLS processes the TTL in the following modes:
●
MPLS TTL processing modes
In MPLS VPN applications, the MPLS backbone network needs to be shielded
to ensure network security. The MPLS Pipe mode on the ingress node is
recommended for private network packets. To reflect the path where packets
pass, use the MPLS Uniform mode on the ingress node.
●
Path where ICMP response packets are transmitted
By default, when the received MPLS packet contains only one label, the LSR
directly sends an ICMP response packet to the sender using an IP route. When
the received MPLS packet contains multiple labels, the LSR sends an ICMP
response packet to the sender along an LSP.
The MPLS VPN packets may contain only one label when they arrive at an
autonomous system boundary router (ASBR) on the MPLS VPN, or a
superstratum PE (SPE) device in HoVPN networking. These devices have no IP
routes to the sender, so they forward the ICMP response packets along an LSP.
The MPLS VPN packets may contain only one label when they arrive at an
autonomous system boundary router (ASBR) on the MPLS VPN. These devices
have no IP routes to the sender, so they forward the ICMP response packets
along an LSP.
Procedure
●
Configuring the MPLS TTL processing mode
Perform the following steps on the ingress node.
a.
Run system-view
The system view is displayed.
b.
Run undo ttl propagate
The MPLS TTL processing mode is set to Pipe.
Or, run ttl propagate
The MPLS TTL processing mode is set to Uniform.
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By default, the TTL propagate function is enabled and the MPLS TTL
processing mode is Uniform.
The ttl propagate command only take effect on LSPs that are to be set up.
Before using the function on LSPs that have been set up, run the reset mpls ldp
command to reestablish the LSPs.
●
Configuring the path where ICMP response packets are transmitted
Perform the following steps on the ingress and egress nodes.
a.
Run system-view
The system view is displayed.
b.
Run mpls
The MPLS view is displayed.
c.
Run undo ttl expiration pop
The device is configured to transmit ICMP response packets along an LSP.
Or, run ttl expiration pop
The device is configured to transmit ICMP response packets using an IP
route.
By default, upon receiving an MPLS packet with one label, an LSR returns
an ICMP response packet using a local IP route.
----End
4.6.13 (Optional) Configuring the LDP Label Policies
Context
The LSR distributes labels to both upstream and downstream LDP peers, which
increases the LDP LSP convergence speed. However, receiving and sending Label
Mapping messages result in the establishments of a large number of LSPs, which
wastes resources. To reduce the number of LSPs and save memory, use the
following policies:
●
Configure the LDP inbound policy.
Configure LDP inbound policy to restrict the receiving of Label Mapping
messages.
●
Configure the LDP split horizon policy.
Access devices on the MPLS network have low performance If LDP distributes
labels to all peers, a large number of LSPs will be established, which cannot
be processed by the LSR. The split horizon policy is recommended.
Procedure
●
Configure an inbound LDP policy.
a.
Run system-view
The system view is displayed.
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b.
4 MPLS LDP Configuration
Run mpls ldp
The MPLS LDP view is displayed.
c.
Run inbound peer { peer-id | peer-group peer-group-name | all } fec
{ none | host | ip-prefix prefix-name }
An inbound policy for allowing the local LSR to receive Label Mapping
messages from a specified LDP peer for a specified IGP route is
configured.
To apply a policy associated with a single Forwarding Equivalence Class
(FEC) range to an LDP peer group or all LDP peers from which the local
LSR receives Label Mapping messages, configure either the peer-group
peer-group-name or all parameter in the command.
If multiple inbound policies are configured for a specified LDP peer, the first
configured one takes effect. For example, the following two inbound policies are
configured:
inbound peer 2.2.2.2 fec host
inbound peer peer-group group1 fec none
As group1 also contains an LDP peer with peer-id of 2.2.2.2, the following
inbound policy takes effect:
inbound peer 2.2.2.2 fec host
If two inbound policies are configured in sequence and the peer parameters in
the two commands are the same, the second command overwrites the first one.
For example, the following two inbound policies are configured:
inbound peer 2.2.2.2 fec host
inbound peer 2.2.2.2 fec none
The second configuration overwrites the first one. This means that the following
inbound policy takes effect on the LDP peer with peer-id of 2.2.2.2:
inbound peer 2.2.2.2 fec none
●
Configure an LDP split horizon policy.
a.
Run system-view
The system view is displayed.
b.
Run mpls ldp
The MPLS LDP view is displayed.
c.
Run outbound peer { peer-id | all } split-horizon
A split horizon policy is configured to distribute labels to only upstream
LDP peers.
By default, split horizon is not enabled and an LSR distributes labels to
both upstream and downstream LDP peers.
The all parameter takes preference over the peer-id parameter. For example, the
outbound peer all split-horizon and then outbound peer 2.2.2.2 split-horizon
commands are run, the outbound peer all split-horizon command can be saved
in the configuration file and take effect, not the outbound peer 2.2.2.2 splithorizon command.
----End
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Follow-up Procedure
●
To delete all inbound policies, run the undo command multiple times to
delete them one by one, or run the undo inbound peer all command to
delete them simultaneously. The first method takes a long time.
●
To delete all outbound policies, run the undo command multiple times to
delete them one by one, or run the undo outbound peer all command to
delete them simultaneously. The first method takes a long time.
4.6.14 (Optional) Disabling a Device from Distributing Labels
to Remote Peers
Context
In MPLS L2VPN scenarios using LDP (including Martini VLL, PWE3, and Martini
VPLS), PEs at both ends need to establish a remote LDP session. The remote LDP
session is only used to transmit Label Mapping messages, so LDP is not required.
By default, LDP allocates common LDP labels to remote peers. Many useless idle
labels are generated, wasting LDP labels.
To solve the preceding problem, disable a device from distributing labels to remote
peers to save system resources. You can use either of the following modes:
●
In the LDP view, disable the PE from distributing labels to all remote peers.
●
In the view of a specified remote peer, disable the PE from distributing labels
to the specified remote peer.
●
Disable a device from distributing labels to a specified remote peer.
Procedure
a.
Run system-view
The system view is displayed.
b.
Run mpls ldp remote-peer remote-peer-name
The remote MPLS LDP peer view is displayed.
c.
Run remote-ip ip-address pwe3
LDP is prevented from allocating public network labels to a specified
remote peer device.
By default, the IP address of the remote LDP peer is not configured.
●
Disable a device from distributing LDP labels to all remote peers.
a.
Run system-view
The system view is displayed.
b.
Run mpls ldp
The MPLS LDP view is displayed.
c.
Run remote-peer pwe3
LDP is prevented from allocating public network labels to all remote peer
devices.
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By default, an LSR is permitted to distribute public network labels to all
remote peers.
----End
4.6.15 (Optional) Configuring a Policy for Triggering LDP LSP
Establishment
Context
After MPLS LDP is enabled, LSPs are automatically established. If no policy is
configured, an increasing number of LSPs are established, wasting resources.
●
Configure the lsp-trigger command on the ingress and egress nodes to
trigger LSP establishment based on routes matching specified conditions. This
setting controls the number of LSPs and saves network resources.
●
Configure the propagate mapping command on the transit node to trigger
LSP establishment based on routes matching specified conditions. For the
routes that do not match specified conditions, the local device does not send
Label Mapping messages to the upstream device, which reduces the number
of LSPs and saves network resources.
By default, the lsp-trigger command is recommended. If this command cannot be
configured on the ingress and egress nodes, configure the propagate mapping
command on the transit node.
Procedure
●
Perform the following steps on the ingress and egress nodes:
a.
Run system-view
The system view is displayed.
b.
Run mpls
The MPLS view is displayed.
c.
Use either the following commands to configure a policy for triggering
LSP establishment.
n
Run lsp-trigger { all | host | ip-prefix ip-prefix-name | none }
A policy for triggering LSP establishment based on static and IGP
routes is configured.
By default, the policy is host. This policy allows LDP to use 32-bit
host routes (except 32-bit host routes of interfaces) to establish LSPs.
LSPs can be established using exactly matching routes on LSRs. On a
loopback interface with 32-bit mask, an LSP can be established only when
an exactly matching host route is available.
n
Run lsp-trigger bgp-label-route [ ip-prefix ip-prefix-name ]
A policy for triggering LSP establishment based on labeled public
BGP routes is configured.
By default, LDP does not distribute labels to labeled public BGP
routes.
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Run proxy-egress disable
The device is disabled from establishing proxy egress LSPs.
By default, a device is enabled to establish proxy egress LSPs.
If a policy allows a device to use all static and IGP routes to establish
LSPs or use an IP address prefix list to establish LSPs, the policy also
triggers proxy egress LSP establishment. However, the proxy egress LSPs
may be unnecessary, wasting system resources. To prevent this problem,
run the proxy-egress disable command to disable a device from
establishing such proxy egress LSPs.
●
Perform the following steps on the transit node:
a.
Run system-view
The system view is displayed.
b.
Run mpls ldp
The MPLS LDP view is displayed.
c.
Run propagate mapping for ip-prefix ip-prefix-name
LDP is configured to establish LSPs based on routes filtered out based on
the IP address prefix list.
By default, when LDP establishes an LSP, LDP does not filter out received
routes.
----End
4.6.16 (Optional) Configuring Delayed Transmission of Label
Withdraw Messages
Context
An LSP on a local node flaps because an LDP session between the node and its
downstream peer flaps, a route flaps, or an LDP policy is modified. The local node
repeatedly sends Label Withdraw and Label Mapping messages in sequence to
upstream nodes. This causes the upstream nodes to repeatedly tear down and
reestablish LSPs. As a result, the entire LDP LSP flaps. The label withdraw delay
function prevents the entire LDP LSP from flapping.
Perform the following steps on each node of an LDP LSP:
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls ldp
The MPLS-LDP view is displayed.
Step 3 Run label-withdraw-delay
The label withdraw delay function is enabled.
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By default, the label withdraw delay function is disabled.
Step 4 Run label-withdraw-delay timer time
The delay time for a Label Withdraw message to be sent is set.
The default delay time is 5 seconds.
----End
4.6.17 (Optional) Enabling LDP to Maintain a Session After
Receiving Error TCP Packets
Context
When a device from another vendor fails or a link fails, the LDP session alternates
between Up and Down. To prevent LDP session flapping and maintain upper-layer
L2VPN services, you can enable LDP to maintain a session after receiving error TCP
packets.
According to RFC5036, LDP tears down a session after receiving error TCP packets.
When a device from another vendor fails or a link fails, the LDP session alternates
between Up and Down after processing in this way. If the LDP transmits L2VPN
services, the L2VPN services will be interrupted. To prevent this problem, enable
LDP to maintain a session after receiving error TCP packets. This prevents LDP
session flapping and helps maintain upper-layer L2VPN services.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls ldp
The MPLS LDP view is displayed.
Step 3 Run maintain-session received-error-message
LDP is enabled to maintain a session after receiving error TCP packets.
By default, LDP tears down a session after receiving error TCP packets.
----End
4.6.18 Verifying the Configuration of Basic MPLS LDP
Functions
Prerequisites
The configurations of the MPLS LDP function are complete.
Procedure
●
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default configurations of the MPLS management module.
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●
Run the display default-parameter mpls ldp command to check the default
configurations of MPLS LDP.
●
Run the display mpls interface [ interface-type interface-number ]
[ verbose ] command to check information about MPLS-enabled interfaces.
●
Run the display mpls ldp [ all ] [ verbose ] command to check LDP
information.
●
Run the display mpls ldp interface [ interface-type interface-number | [ all ]
[ verbose ] ] command to check information about LDP-enabled interfaces.
●
Run the display mpls ldp adjacency [ interface interface-type interfacenumber | remote ] [ peer peer-id ] [ verbose ] command to check
information about LDP adjacencies.
●
Run the display mpls ldp adjacency statistics command to check statistics
about LDP adjacencies.
●
Run the display mpls ldp session [ [ all ] [ verbose ] | peer-id ] command to
check the LDP session status.
●
Run the display mpls ldp session statistics command to check statistics
about sessions between LDP peers.
●
Run the display mpls ldp peer [ [ all ] [ verbose ] | peer-id ] command to
check information about LDP peers.
●
Run the display mpls ldp peer statistics command to check statistics about
LDP peers.
●
Run the display mpls ldp remote-peer [ remote-peer-name | peer-id lsr-id ]
command to check information about the LDP remote peer.
●
Run the display mpls ldp lsp [ all ] command to check LDP LSP information.
●
Run the display mpls ldp lsp statistics command to check statistics about
LDP LSPs.
●
Run the display mpls route-state [ { exclude | include } { idle | ready |
settingup } * | destination-address mask-length ] [ verbose ] command to
check the dynamic LSP route.
●
Run the display mpls lsp [ verbose ] command to check LSP information.
●
Run the display mpls lsp statistics command to check statistics about the
LSPs that are in the Up state and the number of the LSPs that are activated
on the ingress, transit, and egress nodes.
●
Run the display mpls label all summary command to check allocation
information about all MPLS labels.
●
Run the display mpls label-stack ilm inlabel in-label command to check
information about the label stack for packets with a specified incoming label.
----End
4.7 Configuring LDP Extensions for Inter-Area LSPs
Pre-configuration Tasks
Before configuring LDP extensions for inter-area LSPs, complete the following
tasks:
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●
Configure a local LDP session. For details, see 4.6 Configuring Basic
Functions of MPLS LDP.
●
Configure a policy for summarizing routes. For details, see S1720, S2700,
S5700, and S6720 V200R011C10 Configuration Guide - IP Unicast Routing.
LDP extensions for inter-area LSPs enable LDP to search for routes according to
the longest match rule and use summarized routes to establish LDP LSPs spanning
multiple IGP areas.
Context
Perform the following steps on the ingress or transit node.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls ldp
The MPLS LDP view is displayed.
Step 3 Run longest-match
LDP is configured to search for routes based on the longest match rule to
establish LSPs.
By default, LDP searches for routes to establish LSPs based on the exact matching
rule.
----End
Verifying the Configuration
Run the display mpls lsp command to check the setup of inter-area LSPs after
LDP is configured to search for routes based on the longest match rule to
establish LSPs.
4.8 Configuring Static BFD to Detect an LDP LSP
Context
When static BFD monitors an LDP LSP, pay attention to the following points:
●
BFD is bound to only the ingress node of an LDP LSP.
●
One LSP is bound to only one BFD session.
●
The detection only supports the LDP LSP that is triggered to establish by the
host route.
●
The forwarding modes on the forwarding path and reverse path can be
different (for example, an IP packet is sent from the source to the destination
through an LSP, and is sent from the destination to the source in IP
forwarding mode), but the forwarding path and reverse path must be
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established over the same link. If they use different links, BFD cannot identify
the faulty path when a fault is detected.
Static BFD for LDP LSPs fast detects faults on an LDP LSP. Static BFD for LDP LSPs
can be flexibly deployed, but needs to be manually controlled.
Pre-configuration Tasks
Before configuring static BFD to detect an LDP LSP, configure a local LDP session.
For details, see 4.6 Configuring Basic Functions of MPLS LDP.
Configuration Procedure
Configure static BFD for LDP LSPs according to the following sequence.
4.8.1 Configuring BFD with Specific Parameters on the Ingress
Node
Context
BFD parameters on the ingress node include the local and remote discriminators,
intervals for sending and receiving BFD packets, and local BFD detection multiplier.
The BFD parameters affect BFD session setup.
You can adjust the local detection time according to the network situation. On an
unstable link, if a small detection time is used, a BFD session may flap. You can
increase the detection time of the BFD session.
Actual interval for the local device to send BFD packets = MAX {locally configured interval
for sending BFD packets, remotely configured interval for receiving BFD packets }
Actual interval for the local device to receive BFD packets = MAX {remotely configured
interval for sending BFD packets, locally configured interval for receiving BFD packets }
Local detection time = Actual interval for receiving BFD packets x Remotely configured BFD
detection multiplier
Perform the following steps on the ingress node of an LSP:
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run bfd
This node is enabled with the global BFD function. The global BFD view is
displayed.
By default, global BFD is disabled.
Step 3 Run quit
Return to the system view.
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Step 4 Run bfd cfg-name bind ldp-lsp peer-ip ip-address nexthop ip-address [ interface
interface-type interface-number ]
The BFD session is bound to a dynamic LSP.
When the IP address of the egress node on the LSP to be detected is borrowed or
lent, an interface must be specified.
Step 5 Set local and remote discriminators of a BFD session.
●
Run discriminator local discr-value
The local discriminator is configured.
●
Run discriminator remote discr-value
The remote discriminator is configured.
The local and remote identifiers on both ends of a BFD session must be consistent with
each other; otherwise, the session cannot be established correctly. In addition, the local and
remote identifiers cannot be modified after configuration.
Step 6 (Optional) Run min-tx-interval interval
The interval for sending BFD packets is set on the local device.
Step 7 (Optional) Run min-rx-interval interval
The interval for receiving BFD packets is set on the local device.
Step 8 (Optional) Run detect-multiplier multiplier
The local BFD detection multiplier is set.
The default value is 3.
Step 9 Run process-pst
The changes of BFD session status can be advertised to the application on the
upper layer.
By default, a static BFD session cannot report faults of the monitored service
module to the system.
Step 10 Run commit
The configuration is committed.
----End
Follow-up Procedure
When the BFD session is established and its status is Up, the BFD starts to detect
failure in an LDP LSP.
When the LDP LSP is deleted, the BFD status turns Down.
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4.8.2 Configuring BFD with Specific Parameters on the Egress
Node
Context
BFD parameters on the egress node include the local and remote discriminators,
intervals for sending and receiving BFD packets, and local BFD detection multiplier.
The BFD parameters affect BFD session setup.
You can adjust the local detection time according to the network situation. On an
unstable link, if a small detection time is used, a BFD session may flap. You can
increase the detection time of the BFD session.
Actual interval for the local device to send BFD packets = MAX {locally configured interval
for sending BFD packets, remotely configured interval for receiving BFD packets}
Actual interval for the local device to receive BFD packets = MAX {remotely configured
interval for sending BFD packets, locally configured interval for receiving BFD packets}
Local detection time = Actual interval for receiving BFD packets x Remotely configured BFD
detection multiplier
Perform the following steps on the egress node of the LSP.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run bfd
This node is enabled with global BFD. The global BFD view is displayed.
By default, global BFD is disabled.
Step 3 Run quit
Return to the system view.
Step 4 Configure a reverse tunnel to inform the ingress node of a fault if the fault occurs.
The reverse tunnel can be the IP link, LSP, or TE tunnel. To ensure that BFD
packets are received and sent along the same path, an LSP or TE tunnel is
preferentially used to inform the egress node of an LSP fault. If the configured
reverse tunnel requires BFD detection, configure a pair of BFD sessions for it. Run
the following commands as required.
●
For the IP link, run bfd cfg-name bind peer-ip peer-ip [ vpn-instance vpninstance-name ] [ interface interface-type interface-number ] [ source-ip
source-ip ]
●
For the dynamic LSP, run bfd cfg-name bind ldp-lsp peer-ip ip-address
nexthop ip-address [ interface interface-type interface-number ]
●
For the static LSP, run bfd cfg-name bind static-lsp lsp-name
●
For MPLS TE, run bfd cfg-name bind mpls-te interface tunnel interfacenumber [ te-lsp [ backup ] ]
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Step 5 Set local and remote discriminators of a BFD session.
●
Run discriminator local discr-value
The local discriminator is configured.
●
Run discriminator remote discr-value
The remote discriminator is configured.
The local identifier and remote identifier on both ends of a BFD session must accord with
each other. The session cannot be established correctly otherwise. In addition, the local
identifier and remote identifier cannot be modified after configuration.
Step 6 (Optional) Run min-tx-interval interval
The interval for sending BFD packets is set on the local device.
Step 7 (Optional) Run min-rx-interval interval
The interval for receiving BFD packets is set on the local device.
Step 8 (Optional) Run detect-multiplier multiplier
The local BFD detection multiplier is set.
The default value is 3.
Step 9 (Optional) Run process-pst
The changes of the BFD session status can be advertised to the upper-layer
application.
By default, a static BFD session cannot report faults of the monitored service
module to the system.
If an LSP is used as a reverse tunnel to notify the ingress of a fault, you can run
this command to allow the reverse tunnel to switch traffic if the BFD session goes
Down. If a single-hop IP link is used as a reverse tunnel, this command can be
configured. Because the process-pst command can be only configured for BFD
single-link detection.
Step 10 Run commit
The configuration is committed.
----End
4.8.3 Verifying the Configuration of Static BFD for LDP LSPs
Prerequisites
The configurations of the static BFD for LDP LSP are complete.
Procedure
●
Run the display bfd configuration { all | static } command to check the BFD
configuration.
●
Run the display bfd session { all | static } command to check information
about the BFD session.
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●
4 MPLS LDP Configuration
Run the display bfd statistics session { all | static } command to check
statistics about BFD.
----End
4.9 Configuring Dynamic BFD for LDP LSPs
Context
You do not need to specify BFD parameters when configuring dynamic BFD for
LDP LSPs. Dynamic BFD for LDP LSPs speeds up link fault detection and reduces
the configuration workload. This configuration is simple and flexible.
When configuring dynamic BFD for LDP LSPs, pay attention to the following
points:
●
Dynamic BFD only monitors the LDP LSP that is established using a host
route.
●
The forwarding modes on the forwarding path and reverse path can be
different (for example, an IP packet is sent from the source to the destination
through an LSP, and is sent from the destination to the source in IP
forwarding mode), but the forwarding path and reverse path must be
established over the same link. If they use different links, BFD cannot identify
the faulty path when a fault is detected.
Pre-configuration Tasks
Before configuring the dynamic BFD for LDP LSP, configure a local LDP session. For
details, see 4.6 Configuring Basic Functions of MPLS LDP.
Configuration Procedure
Configure dynamic BFD for LDP LSPs according to the following sequence.
4.9.1 Enabling Global BFD Capability
Context
Perform the following steps on the ingress and egress nodes:
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run bfd
Enable BFD globally.
By default, global BFD is disabled.
You can set BFD parameters only after enabling global BFD.
----End
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4.9.2 Enabling MPLS to Dynamically Establish BFD Sessions
Context
You can enable MPLS to dynamically establish BFD sessions after enabling BFD on
the ingress and egress nodes.
Procedure
●
Perform the following steps on the ingress node:
a.
Run system-view
The system view is displayed.
b.
Run mpls
The MPLS view is displayed.
c.
Run mpls bfd enable
An LDP LSP is enabled with the capability of creating BFD session
dynamically.
By default, an ingress cannot dynamically create BFD sessions for
monitoring LDP LSPs.
The BFD session is not created after this command is run.
●
Perform the following steps on the egress node:
a.
Run system-view
The system view is displayed.
b.
Run bfd
The BFD view is displayed.
c.
Run mpls-passive
The function of creating BFD session passively is enabled.
By default, the egress node of an LSP cannot passively create a BFD
session.
Running this command cannot create a BFD session. The BFD session is
not created until the egress node receives the request packet that
contains LSP ping of BFD TLV from the ingress node.
----End
4.9.3 Configuring the Triggering Policy of Dynamic BFD for
LDP LSP
Context
There are two triggering policies to establish the session of dynamic BFD for LDP
LSP:
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●
Host mode: is used when all host addresses are required to be triggered to
create BFD session. You can specify parameters of nexthop and outgoinginterface to define LSPs that can create a BFD session.
●
FEC list mode: is used when only a part of host addresses are required to be
triggered to create a BFD session. You can use the fec-list command to
specify host addresses.
You can configure the triggering policy on the source end of the detected LSP.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 (Optional) If you need the FEC list triggering policy, perform the following
operations in this step:
1.
Run fec-list list-name
A FEC list is created, and the FEC list view is displayed.
By default, no FEC list is created.
2.
Run fec-node ip-address [ nexthop ip-address | outgoing-interface interfacetype interface-number ] *
A FEC node is added to the FEC list.
By default, no FEC node is created.
3.
Run quit
Return to the system view.
Step 3 Run mpls
The MPLS view is displayed.
Step 4 Run mpls bfd-trigger [ host [ nexthop next-hop-address | outgoing-interface
interface-type interface-number ] * | fec-list list-name ]
The triggering policy to establish the session of dynamic BFD for LDP LSP is
configured.
By default, no trigger policy for an LDP BFD session is configured.
After the command is run, the BFD session is started to create.
----End
4.9.4 (Optional) Adjusting BFD Parameters
Context
BFD parameters include the minimum intervals for sending and receiving BFD
packets, and local BFD detection multiplier. The parameters affect BFD session
setup.
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You can adjust the local detection time according to the network situation. On an
unstable link, if a small detection time is used, a BFD session may flap. You can
increase the detection time of the BFD session.
Actual interval for the local device to send BFD packets = MAX {locally configured interval
for sending BFD packets, remotely configured interval for receiving BFD packets}
Actual interval for the local device to receive BFD packets = MAX {remotely configured
interval for sending BFD packets, locally configured interval for receiving BFD packets}
Local detection time = Actual interval for receiving BFD packets x Remotely configured BFD
detection multiplier
Perform the following steps on the ingress node.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run bfd
The BFD view is displayed.
Step 3 Run mpls ping interval interval
The interval for sending LSP ping packets is adjusted.
By default, the interval at which LSP ping packets are sent in a dynamic BFD
session is 60 seconds.
Step 4 Run quit
Exit from the BFD view.
Step 5 Run mpls
The MPLS view is displayed.
Step 6 Run mpls bfd { min-tx-interval tx-interval | min-rx-interval rx-interval | detectmultiplier multiplier }*
BFD time parameters are set.
----End
4.9.5 Verifying the Configuration of Dynamic BFD for LDP
LSPs
Prerequisites
The configurations of the dynamic BFD for LDP LSP function are complete.
Procedure
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Run the display bfd configuration all [ verbose ] command to check the
BFD configuration (ingress).
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●
Run the display bfd configuration passive-dynamic [ peer-ip peer-ip
remote-discriminator discriminator ] [ verbose ] command to check the BFD
configuration (egress).
●
Run the display bfd session all [ verbose ] command to check information
about the BFD session (ingress).
●
Run the display bfd session passive-dynamic [ peer-ip peer-ip remotediscriminator discriminator ] [ verbose ] command to check information
about the BFD established passively (egress).
●
Run the display mpls bfd session [ statistics | protocol ldp | outgoinginterface interface-type interface-number | nexthop ip-address | fec fecaddress | verbose | monitor ] command to check information about MPLS
BFD session (ingress).
----End
4.10 Configuring Synchronization Between LDP and
IGP
Synchronization between LDP and IGP applies to MPLS networks where primary
and backup LSPs exist. LSPs are established between LSRs based on IGP. When the
LDP session on the primary LSP fails (not due to a link failure) or the faulty
primary LSP is restored, you can enable synchronization between LDP and IGP to
prevent traffic interruption caused by the active/standby switchover.
Pre-configuration Tasks
Before configuring synchronization between LDP and IGP, configure a local LDP
session. For details, see 4.6 Configuring Basic Functions of MPLS LDP.
Configuration Procedure
Enabling synchronization between LDP and IGP is mandatory and other tasks are
optional.
4.10.1 Enabling Synchronization Between LDP and IGP
Context
Synchronization between LDP and IGP can be configured in either of the following
modes:
●
Enable this function in the interface view.
This mode allows synchronization between LDP and IGP to be enabled on
interfaces. This mode applies to the scenario where a few interfaces need to
support this function.
●
Enable this function in an IGP process.
This mode allows synchronization between LDP and IGP to be enabled on all
interfaces in the IGP process. This mode applies to the scenario where many
interfaces on a node need to support this function.
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● Synchronization between LDP and IGP can be enabled in IS-IS processes, not in the
interface view.
● If the synchronization status between LDP and IS-IS is different on an interface and
in an IS-IS process, the synchronization status on the interface takes effect.
Procedure
●
If OSPF is used as an IGP, perform the following steps:
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The interface view is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run ospf ldp-sync
Synchronization between LDP and OSPF is enabled on the specified
interface.
By default, synchronization between LDP and OSPF is disabled on an
interface.
●
If IS-IS is used as an IGP, perform the following steps:
Enable synchronization between LDP and IS-IS on an interface.
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The interface view is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run isis enable process-id
IS-IS is enabled.
e.
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Run isis ldp-sync
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Synchronization between LDP and IS-IS is enabled on the specified
interface.
By default, synchronization between LDP and IS-IS is disabled on an
interface.
Enable synchronization between LDP and IS-IS in an IS-IS process.
a.
Run system-view
The system view is displayed.
b.
Run isis [ process-id ]
The IS-IS process view is displayed.
process-id specifies an IS-IS process. If process-id is not specified, the
default IS-IS process ID of the system is 1.
c.
Run ldp-sync enable [ mpls-binding-only ]
Synchronization between LDP and IS-IS is enabled on all interfaces in the
specified IS-IS process.
By default, synchronization between LDP and IS-IS is disabled on all
interfaces in an IS-IS process.
If you want to enable synchronization between LDP and IS-IS on MPLS
LDP-enabled interfaces, please specify the parameter mpls-binding-only.
----End
4.10.2 (Optional) Blocking Synchronization Between LDP and
IS-IS on an Interface
Context
The ldp-sync enable command run in an IS-IS process enables synchronization
between LDP and IS-IS on all local IS-IS interfaces. On an IS-IS interface transmits
importance services, LDP and IS-IS synchronization may affect service
transmission. If the link is working properly and an LDP session over the link fails,
IS-IS sends link state PDUs (LSPs) to advertise the maximum cost of the link. As a
result, IS-IS does not select the route for the link, which affects important service
transmission.
To prevent the preceding problem, block LDP and IS-IS synchronization on an IS-IS
interface that transmits important services.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface interface-type interface-number
The IS-IS interface view is displayed.
Step 3 (Optional) On an Ethernet interface, run undo portswitch
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The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 4 Run isis ldp-sync block
Synchronization between LDP and IS-IS is blocked on the interface.
By default, synchronization between LDP and IS-IS is not blocked on an interface.
----End
4.10.3 (Optional) Setting the Hold-down Timer Value
Context
On a device that has LDP-IGP synchronization enabled, if the active physical link
recovers, an IGP enters the Hold-down state, and a Hold-down timer starts. Before
the Hold-down timer expires, the IGP delays establishing an IGP neighbor
relationship until an LDP session is established over the active link so that the LDP
session over and IGP route for the active link can become available
simultaneously.
If IS-IS is used, you can set the value of the Hold-down timer on a specified interface or set
the value of the Hold-down timer for all IS-IS interfaces in the IS-IS view.
If different Hold-down values on an interface and in an IS-IS process are set, the setting on
the interface takes effect.
Procedure
●
If OSPF is used as an IGP, perform the following steps:
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The interface view is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run ospf timer ldp-sync hold-down value
The interval during which OSPF waits for an LDP session to be
established is set.
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By default, the Hold-down timer value is 10 seconds.
●
If IS-IS is used as an IGP, perform the following steps:
Set the Hold-down timer on a specified IS-IS interface.
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The interface view is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run isis timer ldp-sync hold-down value
The interval during which IS-IS waits for an LDP session to be established
is set.
By default, the Hold-down timer value is 10 seconds.
Set the Hold-down timer on all IS-IS interfaces in a specified IS-IS process.
a.
Run system-view
The system view is displayed.
b.
Run isis [ process-id ]
The IS-IS process view is displayed.
c.
Run timer ldp-sync hold-down value
The Hold-down timer is set, which enables all IS-IS interfaces within an
IS-IS process to delay establishing IS-IS neighbor relationships until LDP
sessions are established.
By default, the Hold-down timer value is 10 seconds.
----End
4.10.4 (Optional) Setting the Hold-max-cost Timer Value
Context
If an LDP session over the active link fails but an IGP route for the active link is
reachable, a node that has LDP-IGP synchronization enabled uses a Hold-max-cost
timer to enable an IGP to advertise LSAs or LSPs carrying the maximum route
cost, which delays IGP route convergence until an LDP session is established.
Therefore, an IGP route for a standby link and an LDP session over the standby
link can become available simultaneously.
You can set the Hold-max-cost timer value in either of the following methods:
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4 MPLS LDP Configuration
Setting the Hold-max-cost timer value in the interface view
You can set the Hold-max-cost timer value on a specified interface. This mode
applies to the scenario where a few interfaces need to use the Hold-max-cost
timer.
●
Setting the Hold-max-cost timer value in the IGP process
After you set the Hold-max-cost timer value in the IGP process, the Holdmax-cost timers on all interfaces in the IGP process are set to this value. This
mode applies to the scenario where many interfaces on a node need to use
the Hold-max-cost timer.
A Hold-max-cost timer can be set on either an OSPF or IS-IS interface and can only be
set in an IS-IS process, not an OSPF process.
If different Hold-max-cost values on an interface and in an IS-IS process are set, the
setting on the interface takes effect.
Select parameters based on networking requirements:
●
If an IGP carries only LDP services, configure the parameter infinite to ensure
that a selected IGP route is kept consistent with the LDP LSP.
●
If an IGP carries multiple types of services including LDP services, set the
value of the parameter value to ensure that a teardown of LDP sessions does
not affect IGP route selection or other services.
●
If OSPF is used as an IGP, perform the following steps:
Procedure
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The interface view is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run ospf timer ldp-sync hold-max-cost { value | infinite }
The interval for advertising the maximum cost in the LSAs of local LSRs
through OSPF is set.
By default, the value of the Hold-max-cost timer is 10 seconds.
●
If IS-IS is used as an IGP, perform the following steps:
Set the Hold-max-cost timer on a specified IS-IS interface.
a.
Run system-view
The system view is displayed.
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4 MPLS LDP Configuration
Run interface interface-type interface-number
The interface view is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run isis timer ldp-sync hold-max-cost { value | infinite }
The value of the Hold-max-cost timer is set.
By default, the value of the Hold-max-cost timer is 10 seconds.
Set the Hold-max-cost timer on all IS-IS interfaces in a specified IS-IS process.
a.
Run system-view
The system view is displayed.
b.
Run isis [ process-id ]
The IS-IS process view is displayed.
c.
Run timer ldp-sync hold-max-cost { infinite | interval }
The Hold-max-cost timer is set, which enables IS-IS to keep advertising
LSPs carrying the maximum route cost on all interfaces within an IS-IS
process.
By default, the value of the Hold-max-cost timer is 10 seconds.
----End
4.10.5 (Optional) Setting the Delay Timer Value
Context
When an LDP session is reestablished on a faulty link, LDP starts the Delay timer
to wait for the establishment of an LSP. After the Delay timer times out, LDP
notifies the IGP that synchronization between LDP and IGP is complete.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface interface-type interface-number
The interface view is displayed.
Step 3 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
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Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 4 Run mpls ldp timer igp-sync-delay value
The period of waiting for the LSP setup after the establishment of the LDP session
is set.
By default, the value of the delay timer is 10s.
----End
4.10.6 Verifying the Configuration of Synchronization
Between LDP and IGP
Prerequisites
The configurations of the synchronization between LDP and IGP function are
complete.
Procedure
●
Run the display ospf ldp-sync interface { all | interface-type interfacenumber } command to check information about synchronization between LDP
and OSPF on an interface.
●
Run the display isis [ process-id ] ldp-sync interface command to check
information about synchronization between LDP and IS-IS on the interface.
●
Run the display rm interface [ interface-type interface-number | vpninstance vpn-instance-name ] command to check information about the
route management.
----End
4.11 Configuring LDP FRR
Pre-configuration Tasks
There are two types of LDP FRR: manual LDP FRR and Auto LDP FRR. Configure
LDP FRR by performing either of the following pre-configuration tasks as required.
●
●
Before configuring manual LDP FRR, complete the following tasks:
–
Configure a local LDP session. For details, see 4.6 Configuring Basic
Functions of MPLS LDP.
–
Configure single-hop BFD if BFD-based manual LDP FRR needs to be
configured. For details, see BFD Configuration in the S1720, S2700,
S5700, and S6720 V200R011C10 Configuration Guide - Reliability.
Before configuring Auto LDP FRR, complete the following tasks:
–
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Functions of MPLS LDP.
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4 MPLS LDP Configuration
Configure IS-IS Auto FRR or OSPF IP FRR. For details about IS-IS Auto
FRR, see Enabling IPv4 IS-IS Auto FRR under IPv4 IS-IS Configuration in
the S1720, S2700, S5700, and S6720 V200R011C10 CLI-based
Configuration - IP Unicast Routing Configuration Guide. For details about
OSPF IP FRR, see Configuring OSPF IP FRR under OSPF Configuration in
the S1720, S2700, S5700, and S6720 V200R011C10 CLI-based
Configuration - IP Unicast Routing Configuration Guide.
To implement millisecond-level switching, perform 4.8 Configuring Static BFD to Detect
an LDP LSP or 4.9 Configuring Dynamic BFD for LDP LSPs.
Context
LDP FRR is classified into the following types:
●
Manual LDP FRR: A backup LSP is configured manually by specifying an
outbound interface or a next hop. The configuration is complex and flexible.
Manual LDP FRR applies to simple networks.
●
Auto LDP FRR: A backup LSP is automatically created based on a specified
policy. The configuration is simple and prevents loops. Auto LDP FRR applies
to complex and large networks.
Select a type according to situations on your network.
Perform the following steps on the ingress or transit node.
Procedure
●
Configuring manual LDP FRR
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The interface view is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run mpls ldp frr nexthop nexthop-address [ ip-prefix ip-prefix-name ]
[ priority priority ]
LDP FRR is enabled on the interface.
By default, no interface is enabled with LDP FRR.
On the same interface, you can configure up to 10 LDP FRR entries with
different precedences. According to different precedences, only one
bypass LSP is generated. The smaller the value is, the higher the
precedence is. By default, the precedence value is 50.
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4 MPLS LDP Configuration
●
LDP FRR cannot be enabled or disabled during the LDP GR.
●
If manual LDP FRR and IP FRR are deployed concurrently, IP FRR is used
preferentially.
●
When the undo mpls ldp command is run to disable the LDP function in
the system view or the undo mpls ldp command is run to disable the LDP
function in the interface view, the LDP FRR configuration in the interface
view is not automatically deleted. Only the LDP FRR function is invalid.
●
In manual LDP FRR configuration, the backup LSP must be in liberal state.
That is, the route state of the bypass LSP from Ingress to Egress node must
be "Inactive Adv".
(Optional) Configuring a Static BFD Session to Report Faults of the
Detected Service Module:
The procedure is only applicable to configure the LDP FRR based on static
BFD.
i.
Run quit
Return to the system view.
ii.
Run bfd session-name
The created BFD session view is displayed.
iii.
Run process-pst
The BFD session is enabled to report faults of the associated LDP LSP
to the system.
By default, a static BFD session cannot report faults of the monitored
service module to the system.
iv.
Run commit
The configuration is committed.
●
Configuring Auto LDP FRR
a.
Run system-view
The system view is displayed.
b.
Run mpls ldp
The MPLS-LDP view is displayed.
c.
Run auto-frr lsp-trigger { all | host | ip-prefix ip-prefix-name | none }
A policy for triggering backup LDP LSP establishment is configured.
By default, LDP uses backup routes to addresses with 32-bit masks to set
up backup LSPs.
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● During the LDP GR process, a policy for triggering the backup LDP LSP
establishment cannot be changed.
● Auto LDP FRR depends on IGP auto FRR. After the frr (IS-IS) or frr (OSPF)
command is used to enable IGP auto FRR, Auto LDP FRR will be automatically
enabled. The auto-frr lsp-trigger command is used to configure or change a
policy for triggering backup LDP LSP establishment.
● If both the auto-frr lsp-trigger command and the lsp-trigger command are
run, the established backup LSPs satisfy both the policy for triggering LDP LSP
establishment and the policy for triggering backup LDP LSP establishment.
----End
Verifying the Configuration
●
Run the display mpls lsp command to check information about LSPs enabled
with LDP FRR.
●
Run the display bfd interface [ interface-type interface-number ] command
to check information about the BFD interface.
4.12 Configuring LDP GR
LDP Graceful Restart (GR) ensures uninterrupted traffic transmission during a
protocol restart or active/standby switchover because the forwarding plane is
separated from the control plane.
Pre-configuration Tasks
Before configuring LDP GR, complete the following tasks:
●
Configure a local LDP session. For details, see 4.6 Configuring Basic
Functions of MPLS LDP.
●
Configure IGP GR. For details, see S1720, S2700, S5700, and S6720
V200R011C10 Configuration Guide - IP Unicast Routing.
Context
Table 4-10 describes timers used during LDP GR.
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Table 4-10 Timers used during LDP GR
Timer
Description
Suggestion
Reconnect
timer
After the GR Restarter
performs an active/standby
switchover, the GR Helper
detects that the LDP session
with the GR Restarter fails,
and then starts the
Reconnect timer and waits
for reestablishment of the
LDP session.
When a network with a large
number of routes is faulty, you
can increase the value of the
Reconnect timer to avoid that all
the LDP sessions cannot recover
within the default timeout period
300s.
The value of the Reconnect
timer that takes effect on
the GR Helper is the smaller
one between the value of
the Neighbor-liveness timer
set on the GR Helper and
the value of Reconnect
timer set on the GR
Restarter.
Recovery
timer
After the LDP session is
reestablished, the GR Helper
starts the Recovery timer
and waits for the recovery
of the LSP.
The value of the Recovery
timer that takes effect on
the GR Helper is the smaller
one between the value of
the Recovery timer set on
the GR Helper and the value
of Recovery timer set on the
GR Restarter.
Neighborliveness timer
The value of the neighborliveness timer defines the
LDP GR period.
The value of the Neighborliveness timer on the GR
Restarter is the same as
that of the Forwarding State
Holding timer.
When a network with a large
number of routes is faulty, you
can increase the value of the
Recovery timer to avoid that all
the LSPs cannot recover within
the default timeout period 300s.
When the number of LSPs on a
network is small, you can set a
smaller value for the Neighborliveness timer to shorten the GR
period.
● Enabling or disabling LDP GR, or changing the LDP GR timer value cause LDP session
reestablishment. To disable a device from re-establishing LDP sessions when LDP GR is
enabled or disabled, or the LDP GR timer valure is changed, run the no-renegotiate
session-parameter-change graceful-restart command in the MPLS-LDP view.
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Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls ldp
The MPLS LDP view is displayed.
Step 3 Run graceful-restart
The LDP GR function is enabled.
By default, the LDP GR function is disabled.
Step 4 (Optional) Run graceful-restart timer reconnect time
The Reconnect timer for the LDP session is set.
By default, the Reconnect timer is set to 300 seconds.
Step 5 (Optional) Run graceful-restart timer recovery time
The LSP Recovery timer is set.
By default, the LSP Recovery timer is set to 300 seconds.
Step 6 (Optional) Run graceful-restart timer neighbor-liveness time
The Neighbor-liveness timer is set.
By default, the Neighbor-liveness timer is 600 seconds.
----End
Verifying the Configuration
●
Run the display mpls graceful-restart command to check information about
GR of all protocols related to MPLS.
●
Run the display mpls ldp event gr-helper command to check GR Helper
information.
●
Run the display mpls ldp [ all ] [ verbose ] command to check information
about LDP.
●
Run the display mpls ldp session [ all ] [ verbose ] command to check
information about the LDP session.
4.13 Configuring LDP Security Mechanisms
LDP security mechanisms such as LDP MD5 authentication, LDP Keychain
authentication, and LDP GTSM can be configured to meet high network security
requirements.
Pre-configuration Tasks
Before configuring LDP security features, configure basic functions of MPLS LDP.
For details, see 4.6 Configuring Basic Functions of MPLS LDP.
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Configuration Procedure
You can perform the following configuration tasks in any sequence as required.
You can configure only either of LDP MD5 authentication and Keychain
authentication for one neighbor at the same time.
4.13.1 Configuring LDP MD5 Authentication
Context
MD5 authentication can be configured for a TCP connection over which an LDP
session is established, improving security. Note that the peers of an LDP session
can be configured with different encryption modes, but must be configured with a
single password.
The MD5 algorithm is easy to configure and generates a single password which
can be changed only manually. MD5 authentication applies to the network
requiring short-period encryption.
Keychain authentication and MD5 authentication cannot be both configured on a
single LDP peer.
LDP authentication configurations are prioritized in descending order: for a single
peer, for a specified peer group, for all peers. Keychain and MD5 configurations of
the same priority are mutually exclusive. Keychain or MD5 authentication can be
configured simultaneously for a specified LDP peer, for this LDP peer in a specified
peer group, and for all LDP peers. The configuration with a higher priority takes
effect. For example, if MD5 authentication is configured for Peer1 and then
keychain authentication is configured for all LDP peers, MD5 authentication takes
effect on Peer1. Keychain authentication takes effect on other peers.
NOTICE
Configuring LDP MD5 authentication may cause LDP session reestablishment,
deletion of the LSP associated with the deleted LDP session, and MPLS service
interruption.
MD5 encryption algorithm cannot ensure security. Keychain authentication is
recommended.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls ldp
The MPLS-LDP view is displayed.
Step 3 Configure LDP MD5 authentication.
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NOTICE
If plain is selected, the password is saved in the configuration file in plain text. In
this case, users at a lower level can easily obtain the password by viewing the
configuration file. This brings security risks. Therefore, it is recommended that you
select cipher to save the password in cipher text.
●
Configure LDP MD5 authentication for a single LDP peer.
Run md5-password { plain | cipher } peer-lsr-id password
MD5 authentication is configured and a password is set.
By default, LDP MD5 authentication is not performed between LDP peers.
●
Configure LDP MD5 authentication for LDP peers in a specified LDP peer
group.
a.
Run md5-password { plain | cipher } peer-group ip-prefix-name
password
MD5 authentication is enabled and a password is set for LDP peers in a
specified LDP peer group.
An IP prefix list can be specified using ip-prefix-name to define the range
of IP addresses in a group. Before using an IP prefix list, ensure that the
IP prefix list must have been created.
b.
(Optional) Run authentication exclude peer peer-id
The device is disabled from authenticating a specified LDP peer.
By default, after LDP MD5 authentication is enabled for a specified LDP
peer group, MD5 authentication takes effect on all LDP peers in the
group. To disable the device from authenticating a specified LDP peer in
the group, perform this step.
●
Configure LDP MD5 authentication for all LDP peers.
a.
Run md5-password { plain | cipher } all password
MD5 authentication is enabled and a password is set for all LDP peers.
b.
(Optional) Run authentication exclude peer peer-id
The device is disabled from authenticating a specified LDP peer.
By default, after LDP MD5 authentication is enabled for all LDP peers,
MD5 authentication takes effect on all LDP peers. To disable the device
from authenticating a specified LDP peer, perform this step.
----End
4.13.2 Configuring LDP Keychain Authentication
Context
To improve LDP session security, keychain authentication can be configured for a
TCP connection over which an LDP session has been established.
Keychain authentication involves a set of passwords and uses a new password
when the previous one expires. Keychain authentication is complex to configure
and applies to a network requiring high security.
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You cannot configure keychain authentication and MD5 authentication for a
neighbor at the same time.
Before configuring LDP keychain authentication, configure keychain globally. For
details about the keychain configuration, see Keychain Configuration in the S1720,
S2700, S5700, and S6720 V200R011C10 Configuration Guide - Security.
LDP authentication configurations are prioritized in descending order: for a single
peer, for a specified peer group, for all peers. Keychain and MD5 configurations of
the same priority are mutually exclusive. Keychain or MD5 authentication can be
configured simultaneously for a specified LDP peer, for this LDP peer in a specified
peer group, and for all LDP peers. The configuration with a higher priority takes
effect. For example, if MD5 authentication is configured for Peer1 and then
keychain authentication is configured for all LDP peers, MD5 authentication takes
effect on Peer1. Keychain authentication takes effect on other peers.
NOTICE
Configuring LDP keychain authentication may cause LDP session reestablishment,
deletion of the LSP associated with the deleted LDP session, and MPLS service
interruption.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls ldp
The MPLS-LDP view is displayed.
Step 3 Configure LDP keychain authentication.
●
Configure LDP keychain authentication for a specified LDP peer.
Run authentication key-chain peer peer-id name keychain-name
LDP keychain is enabled and a keychain name is specified.
By default, LDP keychain authentication is not performed between LDP peers.
●
Configure LDP keychain authentication for LDP peers in a specified LDP peer
group.
a.
Run authentication key-chain peer-group ip-prefix-name name
keychain-name
LDP keychain is enabled and a keychain name is specified for a specified
LDP peer group.
An IP prefix list can be specified using ip-prefix-name to define the range
of IP addresses in a group. Before using an IP prefix list, ensure that the
IP prefix list must have been created.
b.
(Optional) Run authentication exclude peer peer-id
The device is disabled from authenticating a specified LDP peer.
By default, after LDP keychain authentication is enabled for a specified
LDP peer group, keychain authentication takes effect on all LDP peers in
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the group. To disable the device from authenticating a specified LDP peer,
perform this step.
●
Configure LDP keychain authentication for all LDP peers.
a.
Run authentication key-chain all name keychain-name
LDP keychain is enabled and a keychain name is specified for all LDP
peers.
b.
(Optional) Run authentication exclude peer peer-id
The device is disabled from authenticating a specified LDP peer.
By default, after LDP keychain authentication is enabled for all LDP peers,
keychain authentication takes effect on all LDP peers. To disable the
device from authenticating a specified LDP peer, perform this step.
----End
4.13.3 Configuring the LDP GTSM
Context
To protect device from attacks, Generalized TTL Security Mechanism (GTSM)
checks the TTL value of a packet to check whether the packet is valid. To check
the TTL value of an LDP packet exchanged between LDP peers, enable GTSM on
LDP peers and set the TTL range. If the TLL of an LDP packet is out of the TTL
range, the LDP packet is considered as an invalid attack packet and discarded. This
prevents the CPU from processing a large number of forged LDP packets. In this
way, the upper layer protocols are protected.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls ldp
The MPLS-LDP view is displayed.
Step 3 Run gtsm peer ip-address valid-ttl-hops hops
The LDP GTSM is configured.
By default, no LDP peer is configured with the GTSM.
hops is the maximum number of valid hops permitted by the GTSM. If a TTL value
carried in a received packet is in a specified range of [255 - hops + 1, 255], the
packet is accepted; if the TTL value is out of the range, the packet is discarded.
----End
4.13.4 Verifying the Configuration of LDP Security
Mechanisms
Prerequisites
The configurations of LDP security features are complete.
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Procedure
●
Run the display mpls ldp session verbose command to check the
configurations of LDP MD5 authentication and LDP keychain authentication.
●
Run the display gtsm statistics all command to check GTSM statistics.
----End
4.14 Configuring Non-labeled Public Network Routes
to Be Iterated to LSPs
By default, non-labeled public network routes can be iterated to outgoing
interfaces and next hops, but cannot be iterated to tunnels. After this feature is
configured, non-labeled public network routes can be iterated to LSPs.
Pre-configuration Tasks
Before configuring non-labeled public network routes to be iterated to LSPs,
complete the following tasks:
●
Configure a local LDP session. For details, see 4.6 Configuring Basic
Functions of MPLS LDP.
●
Configure an IP prefix list if non-labeled public network routes to be iterated
to LSPs need to be limited.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run route recursive-lookup tunnel [ only ] [ ip-prefix ip-prefix-name ]
The non-label public network route is allowed to be iterated to the LSP to forward
through MPLS.
By default, the non-label public network route can be iterated only to the
outbound interface and the next hop but not the LSP tunnel.
If ip-prefix ip-prefix-name is not set, all static routes and non-labeled public BGP
routes will be preferentially iterated to LSP tunnels.
----End
Verifying the Configuration
After non-labeled public routes are iterated to LSPs, you can run the display bgp
routing-table network command to view route iteration information.
4.15 Maintaining MPLS LDP
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4 MPLS LDP Configuration
4.15.1 Resetting LDP
Context
NOTICE
● Resetting LDP may temporarily affect the reestablishment of the LSP. Exercise
caution when you reset LDP.
● Resetting LDP is prohibited during the LDP GR.
Procedure
●
Run the reset mpls ldp command to reset configurations of the global LDP
instance in the user view.
●
Run the reset mpls ldp all command to reset configurations on all LDP
instances in the user view.
●
Run the reset mpls ldp peer peer-id command to reset a specified peer in the
user view.
----End
4.15.2 Clearing LDP Statistics
Context
NOTICE
The cleared LDP statistics cannot be restored. Exercise caution when you use the
following commands.
Procedure
●
Run the reset mpls ldp error packet { tcp | udp | l2vpn | all } command in
the user view to clear statistics on LDP error messages.
●
Run the reset mpls ldp event adjacency-down command in the user view to
clear statistics on LDP adjacencies in Down state.
●
Run the reset mpls ldp event session-down command in the user view to
clear statistics on LDP sessions in Down state.
----End
4.15.3 Monitoring the LDP Running Status
Context
In routine maintenance, you can run the following commands in any view to view
the LDP running status.
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4 MPLS LDP Configuration
Procedure
●
Run the display mpls ldp error packet { tcp | udp | l2vpn } [ number ]
command to check statistics on LDP error messages.
●
Run the display mpls ldp error packet state command to check the record
status of LDP-related error messages.
●
Run the display mpls ldp event adjacency-down [ interface interface-type
interface-number | remote ] [ peer peer-id ] [ verbose ] command to check
information about LDP adjacencies in Down state.
●
Run the display mpls ldp event session-down command to check
information about LDP sessions in Down state.
●
Run the display mpls last-info lsp-down [ protocol ldp ] [ verbose ]
command to check information about LDP LSPs in Down state.
----End
4.15.4 Verifying the LSP Connectivity
Context
In MPLS, the control panel used for setting up an LSP cannot detect data
forwarding failures on the LSP. This makes network maintenance difficult.
MPLS ping checks LSP connectivity, and MPLS traceroute locates network faults in
addition to checking LSP connectivity.
MPLS ping and MPLS traceroute can be performed in any view. MPLS ping and
MPLS traceroute do not support packet fragmentation.
Procedure
Step 1 Run the system-view command to enter the system view.
Step 2 Run the lspv mpls-lsp-ping echo enable command to enable the response to
MPLS Echo Request packets.
By default, the device is enabled to respond to MPLS Echo Request packets.
Step 3 (Optional) Run the lspv packet-filter acl-number command to enable MPLS Echo
Request packet filtering based on source IP addresses. The filtering rule is specified
in the ACL.
By default, the device does not filter MPLS Echo Request packets based on their
source IP addresses.
Step 4 Run the following command to check the LSP connectivity.
●
Run the ping lsp [ -a source-ip | -c count | -exp exp-value | -h ttl-value | -m
interval | -r reply-mode | -s packet-size | -t time-out | -v ] * ip destinationaddress mask-length [ ip-address ] [ nexthop nexthop-address | draft6 ]
command to perform an MPLS ping test.
If draft6 is specified, the command is implemented according to draft-ietfmpls-lsp-ping-06. By default, the command is implemented according to RFC
4379.
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●
4 MPLS LDP Configuration
Run the tracert lsp [ -a source-ip | -exp exp-value | -h ttl-value | -r replymode | -t time-out | -v ] * ip destination-address mask-length [ ip-address ]
[ nexthop nexthop-address | draft6 ] command to perform an MPLS
traceroute test.
If draft6 is specified, the command is implemented according to draft-ietfmpls-lsp-ping-06. By default, the command is implemented according to RFC
4379.
----End
Follow-up Procedure
●
Run the display lspv statistics command to check the LSPV test statistics. A
large amount of statistical information is saved in the system after MPLS ping
or traceroute tests are performed multiple times, which is unhelpful for
problem analysis. To obtain more accurate statistics, run the reset lspv
statistics command to clear LSPV test statistics before running the display
lspv statistics command.
●
Run the undo lspv mpls-lsp-ping echo enable command to disable response
to MPLS Echo Request packets. It is recommended that you run this command
after completing an MPLS ping or traceroute test to save system resources.
●
Run the display lspv configuration command to check the current LSPV
configuration.
4.15.5 Enabling the MPLS Trap Function
Context
To facilitate operation and maintenance and learn about the running status of the
MPLS network, configure the MPLS trap function so that the device can notify the
NMS of the LDP session status and usage of LDP LSPs, BGP LSPs and dynamic
labels.
If the proportion of used MPLS resources, such as LSPs, dynamic labels, and
dynamic BFD sessions to all supported ones reaches a specified upper limit, new
MPLS services may fail to be established because of insufficient resources. To
facilitate operation and maintenance, an upper alarm threshold of MPLS resource
usage can be set. If MPLS resource usage reaches the specified upper alarm
threshold, an alarm is generated.
Procedure
●
Configuring the trap function for LDP
a.
Run the system-view command to enter the system view.
b.
Run the snmp-agent trap enable feature-name ldp trap-name
{ session-down-mib | session-pvl | session-retry | session-up-mib }
command to enable the trap function for the MPLS LDP module.
By default, the trap function is disabled for the MPLS LDP module.
●
Configure the trap function for LSPM.
a.
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b.
4 MPLS LDP Configuration
Run the snmp-agent trap enable feature-name mpls_lspm trap-name
trapname command to enable the trap function for the LSPM module.
By default, the trap function is disabled for the LSPM module.
When performing the following steps to configure alarm thresholds, pay
attention to the following points:
c.
n
To configure the alarm function for dynamic label usage, specify
hwMplsDynamicLabelThresholdExceed and
hwMplsDynamicLabelThresholdExceedClear to enable the
threshold exceeding alarm and clear alarm when configuring trapname. When the usage of dynamic labels exceeds the upper
threshold or falls below the lower threshold, the system generates a
threshold exceeding alarm or clear alarm.
n
To configure the LSP usage alarm function, specify
hwmplslspthresholdexceed and hwmplslspthresholdexceedclear
to enable the threshold exceeding alarm and clear alarm when
configuring trap-name. When the LSP usage exceeds the upper
threshold or falls below the lower threshold, the system generates a
threshold exceeding alarm or clear alarm.
Run the snmp-agent trap suppress feature-name lsp trap-name
{ mplsxcup | mplsxcdown } trap-interval trap-interval [ max-trapnumber max-trap-number ] command to set the interval for suppressing
excess LSP traps.
By default, the interval for suppressing the display of excessive LSP traps
is 300 seconds, and a maximum of three LSP traps can be sent in the
suppression interval.
d.
Run the mpls command to enter the MPLS view.
e.
Run the mpls dynamic-label-number threshold-alarm upper-limit
upper-limit-value lower-limit lower-limit-value command to set alarm
thresholds for dynamic label usage.
You can set the following parameters:
n
upper-limit-value: a percent indicating the upper limit of dynamic
labels. If dynamic label usage reaches the upper limit, an alarm is
generated. An upper limit less than or equal to 95% is
recommended.
n
lower-limit-value: a percent indicating the lower limit of dynamic
labels. If dynamic label usage falls below the lower limit, an alarm is
generated.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
By default, the upper limit is 80%, and the lower limit is 70%, which are
recommended.
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● Each command only configures the trigger conditions for an alarm and its
clear alarm. Although trigger conditions are met, the alarm and its clear
alarm can be generated only after the snmp-agent trap enable featurename mpls_lspm trap-name { hwMplsDynamicLabelThresholdExceed |
hwMplsDynamicLabelThresholdExceedClear } command is run to enable
the device to generate a dynamic label insufficiency alarm and its clear alarm.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwMplsDynamicLabelTotalCountExceed |
hwMplsDynamicLabelTotalCountExceedClear } command is run to enable
the device to generate limit-reaching alarms and their clear alarms, the
following situations occur:
f.
●
If the number of dynamic labels reaches the maximum number of
dynamic labels supported by a device, a limit-reaching alarm is
generated.
●
If the number of dynamic labels falls below 95% of the maximum
number of dynamic labels supported by the device, a clear alarm is
generated.
Run the mpls ldp-lsp-number [ ingress | transit | egress ] thresholdalarm upper-limit upper-limit-value lower-limit lower-limit-value
command to configure the upper and lower thresholds of alarms for LDP
LSP usage.
The parameters in this command are described as follows:
n
upper-limit-value specifies the upper threshold of alarms for LDP LSP
usage. An alarm is generated when the proportion of established
LDP LSPs to total supported LDP LSPs reaches the upper limit.
n
lower-limit-value specifies the lower threshold of clear alarms for
LDP LSP usage. A clear alarm is generated when the proportion of
established LDP LSPs to total supported LDP LSPs falls below the
lower limit.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
The default upper limit of an alarm for LDP LSP usage is 80%. The
default lower limit of a clear alarm for LDP LSP usage is 75%. Using the
default upper limit and lower limit is recommended.
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● This command configures the alarm threshold for LDP LSP usage. The alarm
that the number of LSPs reached the upper threshold is generated only when
the command snmp-agent trap enable feature-name mpls_lspm trapname hwmplslspthresholdexceed is configured, and the actual LDP LSP
usage reaches the upper limit of the alarm threshold. The alarm that the
number of LSPs fell below the lower threshold is generated only when the
command snmp-agent trap enable feature-name mpls_lspm trap-name
hwmplslspthresholdexceedclear is configured, and the actual LDP LSP usage
falls below the lower limit of the clear alarm threshold.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwmplslsptotalcountexceed | hwmplslsptotalcountexceedclear }
command is run to enable LSP limit-crossing alarm and LSP limit-crossing
clear alarm, an alarm is generated in the following situations:
g.
●
If the total number of LDP LSPs reaches the upper limit, a limit-crossing
alarm is generated.
●
If the total number of LDP LSPs falls below 95% of the upper limit, a
limit-crossing clear alarm is generated.
Run the mpls bgp-lsp-number [ ingress | egress ] threshold-alarm
upper-limit upper-limit-value lower-limit lower-limit-value command to
configure the upper and lower thresholds of alarms for BGP LSP usage.
The parameters in this command are described as follows:
n
upper-limit-value specifies the upper threshold of alarms for BGP LSP
usage. An alarm is generated when the proportion of established
BGP LSPs to total supported BGP LSPs reaches the upper limit.
n
lower-limit-value specifies the lower threshold of clear alarms for
BGP LSP usage. A clear alarm is generated when the proportion of
established BGP LSPs to total supported BGP LSPs falls below the
lower limit.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
The default upper limit of an alarm for BGP LSP usage is 80%. The
default lower limit of a clear alarm for BGP LSP usage is 75%. Using the
default upper limit and lower limit is recommended.
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● This command configures the alarm threshold for BGP LSP usage. The alarm
that the number of LSPs reached the upper threshold is generated only when
the command snmp-agent trap enable feature-name mpls_lspm trapname hwmplslspthresholdexceed is configured, and the actual BGP LSP
usage reaches the upper limit of the alarm threshold. The alarm that the
number of LSPs fell below the lower threshold is generated only when the
command snmp-agent trap enable feature-name mpls_lspm trap-name
hwmplslspthresholdexceedclear is configured, and the actual BGP LSP
usage falls below the lower limit of the clear alarm threshold.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwmplslsptotalcountexceed | hwmplslsptotalcountexceedclear }
command is run to enable LSP limit-crossing alarm and LSP limit-crossing
clear alarm, an alarm is generated in the following situations:
h.
●
If the total number of BGP LSPs reaches the upper limit, a limit-crossing
alarm is generated.
●
If the total number of BGP LSPs falls below 95% of the upper limit, a
limit-crossing clear alarm is generated.
Run the mpls bgpv6-lsp-number [ egress ] threshold-alarm upperlimit upper-limit-value lower-limit lower-limit-value command to
configure the upper and lower thresholds of alarms for BGP IPv6 LSP
usage.
The parameters in this command are described as follows:
n
upper-limit-value specifies the upper threshold of alarms for BGP
IPv6 LSP usage. An alarm is generated when the proportion of
established BGP IPv6 LSPs to total supported BGP IPv6 LSPs reaches
the upper limit.
n
lower-limit-value specifies the lower threshold of clear alarms for
BGP IPv6 LSP usage. A clear alarm is generated when the proportion
of established BGP IPv6 LSPs to total supported BGP IPv6 LSPs falls
below the lower limit.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
The default upper limit of an alarm for BGP IPv6 LSP usage is 80%. The
default lower limit of a clear alarm for BGP IPv6 LSP usage is 75%. Using
the default upper limit and lower limit is recommended.
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● This command configures the alarm threshold for BGP IPv6 LSP usage. The
alarm that the number of LSPs reached the upper threshold is generated only
when the command snmp-agent trap enable feature-name mpls_lspm
trap-name hwmplslspthresholdexceed is configured, and the actual BGP
IPv6 LSP usage reaches the upper limit of the alarm threshold. The alarm that
the number of LSPs fell below the lower threshold is generated only when the
command snmp-agent trap enable feature-name mpls_lspm trap-name
hwmplslspthresholdexceedclear is configured, and the actual BGP IPv6 LSP
usage falls below the lower limit of the clear alarm threshold.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwmplslsptotalcountexceed | hwmplslsptotalcountexceedclear }
command is run to enable LSP limit-crossing alarm and LSP limit-crossing
clear alarm, an alarm is generated in the following situations:
i.
●
If the total number of BGP IPv6 LSPs reaches the upper limit, a limitcrossing alarm is generated.
●
If the total number of BGP IPv6 LSPs falls below 95% of the upper limit,
a limit-crossing clear alarm is generated.
Run the mpls total-lsp-number [ ingress | transit | egress ] thresholdalarm upper-limit upper-limit-value lower-limit lower-limit-value
command to configure the upper and lower thresholds of alarms for total
LSP usage.
The parameters in this command are described as follows:
n
upper-limit-value specifies the upper threshold of alarms for total
LSP usage. An alarm is generated when the proportion of established
LSPs to total supported LSPs reaches the upper limit.
n
lower-limit-value specifies the lower threshold of clear alarms for
total LSP usage. A clear alarm is generated when the proportion of
established LSPs to total supported LSPs falls below the lower limit.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
The default upper limit of an alarm for total LSP usage is 80%. The
default lower limit of a clear alarm for total LSP usage is 75%. Using the
default upper limit and lower limit is recommended.
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● This command configures the alarm threshold for total LSP usage. The alarm
that the number of LSPs reached the upper threshold is generated only when
the command snmp-agent trap enable feature-name mpls_lspm trapname hwmplslspthresholdexceed is configured, and the actual total LSP
usage reaches the upper limit of the alarm threshold. The alarm that the
number of LSPs fell below the lower threshold is generated only when the
command snmp-agent trap enable feature-name mpls_lspm trap-name
hwmplslspthresholdexceedclear is configured, and the actual total LSP
usage falls below the lower limit of the clear alarm threshold.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwmplslsptotalcountexceed | hwmplslsptotalcountexceedclear }
command is run to enable LSP limit-crossing alarm and LSP limit-crossing
clear alarm, an alarm is generated in the following situations:
●
●
If the total number of LSPs reaches the upper limit, a limit-crossing
alarm is generated.
●
If the total number of LSPs falls below 95% of the upper limit, a limitcrossing clear alarm is generated.
Configure MPLS resource threshold-related alarms.
a.
Run the system-view command to enter the system view.
b.
Run the mpls command to enter the MPLS view.
c.
Run the mpls bfd-ldp-number threshold-alarm upper-limit upper-limitvalue lower-limit lower-limit-value command to configure the conditions
that trigger the threshold-reaching alarm and its clear alarm for dynamic
BFD sessions for LDP.
Note the following issues when configuring trigger conditions:
n
upper-limit-value: upper alarm threshold for the proportion of used
LDP resources to all LDP resources supported by a device.
n
lower-limit-value: lower alarm threshold for the proportion of used
LDP resources to all LDP resources supported by a device.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
By default, the upper alarm threshold is 80%, and the lower alarm
threshold is 75%, which are recommended.
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4 MPLS LDP Configuration
● Each command only configures the trigger conditions for an alarm and its
clear alarm. Although trigger conditions are met, the alarm and its clear
alarm can be generated only after the snmp-agent trap enable featurename mpls_lspm trap-name { hwmplsresourcethresholdexceed |
hwmplsresourcethresholdexceedclear } command is run to enable the
device to generate an LDP resource insufficiency alarm and its clear alarm.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwmplsresourcetotalcountexceed |
hwmplsresourcetotalcountexceedclear } command is run to enable the
device to generate limit-reaching alarms and their clear alarms, the following
situations occur:
d.
●
If the number of used LDP resources reaches the maximum number of
LDP resources supported by a device, a limit-reaching alarm is
generated.
●
If the number of used LDP resources falls below 95% of the maximum
number of LDP resources supported by the device, a clear alarm is
generated.
Run the mpls remote-adjacency-number threshold-alarm upper-limit
upper-limit-value lower-limit lower-limit-value command to configure
the conditions that trigger the threshold-reaching alarm and its clear
alarm for remote LDP adjacencies.
Note the following issues when configuring trigger conditions:
n
upper-limit-value: upper alarm threshold of the proportion of used
LDP resources to all LDP resources supported by a device.
n
lower-limit-value: lower alarm threshold for the proportion of used
LDP resources to all LDP resources supported by a device.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
By default, the upper alarm threshold is 80%, and the lower alarm
threshold is 75%, which are recommended.
● Each command only configures the trigger conditions for an alarm and its
clear alarm. Although trigger conditions are met, the alarm and its clear
alarm can be generated only after the snmp-agent trap enable featurename mpls_lspm trap-name { hwmplsresourcethresholdexceed |
hwmplsresourcethresholdexceedclear } command is run to enable the
device to generate an LDP resource insufficiency alarm and its clear alarm.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwmplsresourcetotalcountexceed |
hwmplsresourcetotalcountexceedclear } command is run to enable the
device to generate limit-reaching alarms and their clear alarms, the following
situations occur:
●
If the number of used LDP resources reaches the maximum number of
LDP resources supported by a device, a limit-reaching alarm is
generated.
●
If the number of used LDP resources falls below 95% of the maximum
number of LDP resources supported by the device, a clear alarm is
generated.
----End
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4 MPLS LDP Configuration
Verifying the Configuration
●
Run the display snmp-agent trap feature-name ldp all command to check
the status of all traps on the MPLS LDP module.
●
Run the display snmp-agent trap feature-name mpls_lspm all command to
check all trap messages on the MPLS LSPM module.
●
Run the display default-parameter mpls management command to check
default configurations of the MPLS management module.
4.16 Configuration Examples for MPLS LDP
4.16.1 Example for Configuring Local LDP Sessions
Networking Requirements
As shown in Figure 4-14, LSRA and LSRC are PEs of the IP/MPLS backbone
network. MPLS L2VPN or L3VPN services need to be deployed on LSRA and LSRC
to connect VPN sites, so local LDP sessions need to be established between LSRs
to trigger LDP LSP setup. The LDP LSPs then transmit VPN services.
Figure 4-14 Networking diagram for configuring local LDP sessions
IP/MPLS backbone network
Loopback0
Loopback0
Loopback0
1.1.1.1/32
2.2.2.2/32
3.3.3.3/32
GE0/0/1
GE0/0/2
GE0/0/1 GE0/0/1
10.2.1.1/24 10.2.1.2/24
10.1.1.1/2410.1.1.2/24
VLANIF10 VLANIF10
VLANIF20 VLANIF20
LSRA
LSRB
LSRC
VPN Site
VPN Site
Configuration Roadmap
The configuration roadmap is as follows:
1.
Configure OSPF between the LSRs to implement IP connectivity on the
backbone network.
2.
Configure local LDP sessions on LSRs so that public tunnels can be set up to
transmit VPN services.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
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# Configure LSRA. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 0
[LSRA-LoopBack0] ip address 1.1.1.1 32
[LSRA-LoopBack0] quit
[LSRA] vlan batch 10
[LSRA] interface vlanif 10
[LSRA-Vlanif10] ip address 10.1.1.1 24
[LSRA-Vlanif10] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure LSRA.
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.1 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
# Configure LSRB.
[LSRB] ospf 1
[LSRB-ospf-1] area 0
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1] quit
network 2.2.2.2 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
quit
# Configure LSRC.
[LSRC] ospf 1
[LSRC-ospf-1] area 0
[LSRC-ospf-1-area-0.0.0.0] network 3.3.3.3 0.0.0.0
[LSRC-ospf-1-area-0.0.0.0] network 10.2.1.0 0.0.0.255
[LSRC-ospf-1-area-0.0.0.0] quit
[LSRC-ospf-1] quit
After the configuration is complete, run the display ip routing-table command
on each node, and you can view that the nodes learn routes from each other.
Step 3 Enable global MPLS and MPLS LDP on each LSR.
# Configure LSRA.
[LSRA] mpls lsr-id 1.1.1.1
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
# Configure LSRB.
[LSRB] mpls lsr-id 2.2.2.2
[LSRB] mpls
[LSRB-mpls] quit
[LSRB] mpls ldp
[LSRB-mpls-ldp] quit
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# Configure LSRC.
[LSRC] mpls lsr-id 3.3.3.3
[LSRC] mpls
[LSRC-mpls] quit
[LSRC] mpls ldp
[LSRC-mpls-ldp] quit
Step 4 Enable MPLS and MPLS LDP on interfaces of each LSR.
# Configure LSRA.
[LSRA] interface vlanif 10
[LSRA-Vlanif10] mpls
[LSRA-Vlanif10] mpls ldp
[LSRA-Vlanif10] quit
# Configure LSRB.
[LSRB] interface vlanif 10
[LSRB-Vlanif10] mpls
[LSRB-Vlanif10] mpls ldp
[LSRB-Vlanif10] quit
[LSRB] interface vlanif 20
[LSRB-Vlanif20] mpls
[LSRB-Vlanif20] mpls ldp
[LSRB-Vlanif20] quit
# Configure LSRC.
[LSRC] interface vlanif 20
[LSRC-Vlanif20] mpls
[LSRC-Vlanif20] mpls ldp
[LSRC-Vlanif20] quit
Step 5 Verify the configuration.
# After the configuration is complete, run the display mpls ldp session command.
The command output shows that the status of local LDP sessions between LSRA
and LSRB and between LSRB and LSRC is Operational.
LSRA is used as an example.
[LSRA] display mpls ldp session
LDP Session(s) in Public Network
Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDDD:HH:MM)
A '*' before a session means the session is being deleted.
-----------------------------------------------------------------------------PeerID
Status
LAM SsnRole SsnAge
KASent/Rcv
-----------------------------------------------------------------------------2.2.2.2:0
Operational DU Passive 0000:00:22 91/91
-----------------------------------------------------------------------------TOTAL: 1 session(s) Found.
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 10
#
mpls lsr-id 1.1.1.1
mpls
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#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.1 0.0.0.0
network 10.1.1.0 0.0.0.255
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 10 20
#
mpls lsr-id 2.2.2.2
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 2.2.2.2 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.2 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 20
#
mpls lsr-id 3.3.3.3
mpls
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#
mpls ldp
#
interface Vlanif20
ip address 10.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 3.3.3.3 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.3 0.0.0.0
network 10.2.1.0 0.0.0.255
#
return
4.16.2 Example for Configuring Remote MPLS LDP Sessions
Networking Requirements
As shown in Figure 4-15, LSRA and LSRC are PEs of the IP/MPLS backbone
network. MPLS L2VPN services need to be deployed on LSRA and LSRC to connect
VPN sites at Layer 2, so remote LDP sessions need to be deployed between LSRA
and LSRC to implement VC label exchange.
Figure 4-15 Networking diagram for configuring remote LDP sessions
IP/MPLS backbone network
Loopback0
Loopback0
Loopback0
1.1.1.1/32
2.2.2.2/32
3.3.3.3/32
GE0/0/1
GE0/0/2
GE0/0/1 GE0/0/1
10.2.1.1/24 10.2.1.2/24
10.1.1.1/2410.1.1.2/24
VLANIF10 VLANIF10
VLANIF20 VLANIF20
LSRA
LSRB
LSRC
VPN Site
VPN Site
Configuration Roadmap
If LSRA is directly connected to LSRC, local LDP sessions established on LSRs can
be used to set up LDP LSPs to transmit services and exchange VC labels. In this
example, LSRA is indirectly connected to LSRC, so remote LDP sessions must be
configured. The configuration roadmap is as follows:
1.
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backbone network.
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2.
4 MPLS LDP Configuration
Configure remote LDP sessions on LSRA and LSRC to exchange VC labels.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
# Configure LSRA. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 0
[LSRA-LoopBack0] ip address 1.1.1.1 32
[LSRA-LoopBack0] quit
[LSRA] vlan batch 10
[LSRA] interface vlanif 10
[LSRA-Vlanif10] ip address 10.1.1.1 24
[LSRA-Vlanif10] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure LSRA.
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.1 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
# Configure LSRB.
[LSRB] ospf 1
[LSRB-ospf-1] area 0
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1] quit
network 2.2.2.2 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
quit
# Configure LSRC.
[LSRC] ospf 1
[LSRC-ospf-1] area 0
[LSRC-ospf-1-area-0.0.0.0] network 3.3.3.3 0.0.0.0
[LSRC-ospf-1-area-0.0.0.0] network 10.2.1.0 0.0.0.255
[LSRC-ospf-1-area-0.0.0.0] quit
[LSRC-ospf-1] quit
After the configuration is complete, run the display ip routing-table command
on each node, and you can view that the nodes learn routes from each other.
Step 3 Enable global MPLS and MPLS LDP on each LSR.
# Configure LSRA.
[LSRA] mpls lsr-id 1.1.1.1
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
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# Configure LSRB.
[LSRB] mpls lsr-id 2.2.2.2
[LSRB] mpls
[LSRB-mpls] quit
[LSRB] mpls ldp
[LSRB-mpls-ldp] quit
# Configure LSRC.
[LSRC] mpls lsr-id 3.3.3.3
[LSRC] mpls
[LSRC-mpls] quit
[LSRC] mpls ldp
[LSRC-mpls-ldp] quit
Step 4 Specify the name and IP address of the remote peer on the two LSRs of a remote
LDP session.
# Configure LSRA.
[LSRA] mpls ldp remote-peer LSRC
[LSRA-mpls-ldp-remote-lsrc] remote-ip 3.3.3.3
[LSRA-mpls-ldp-remote-lsrc] quit
# Configure LSRC.
[LSRC] mpls ldp remote-peer LSRA
[LSRC-mpls-ldp-remote-lsra] remote-ip 1.1.1.1
[LSRC-mpls-ldp-remote-lsra] quit
Step 5 Verify the configuration.
# After the configuration is complete, run the display mpls ldp session command
on the node. The command output shows that the status of the remote LDP
session between LSRA and LSRC is Operational.
LSRA is used as an example.
[LSRA] display mpls ldp session
LDP Session(s) in Public Network
Codes: LAM(Label Advertisement Mode), SsnAge
Unit(DDDD:HH:MM)
A '*' before a session means the session is being deleted.
-------------------------------------------------------------------------PeerID
Status
LAM SsnRole SsnAge
KASent/Rcv
-------------------------------------------------------------------------3.3.3.3:0
Operational DU Passive 0000:00:01 6/6
-------------------------------------------------------------------------TOTAL: 1 session(s) Found.
# Run the display mpls ldp remote-peer command on the two LSRs of the
remote LDP session to view information about the remote peer.
LSRA is used as an example.
[LSRA] display mpls ldp remote-peer
LDP Remote Entity Information
-----------------------------------------------------------------------------Remote Peer Name : lsrc
Remote Peer IP : 3.3.3.3
LDP ID
: 1.1.1.1:0
Transport Address : 1.1.1.1
Entity Status : Active
Configured Keepalive Hold Timer : 45 Sec
Configured Keepalive Send Timer : --Configured Hello Hold Timer
: 45 Sec
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Negotiated Hello Hold Timer
: 45 Sec
Configured Hello Send Timer
: --Configured Delay Timer
: 10 Sec
Hello Packet sent/received
: 6347/6307
Label Advertisement Mode
: Downstream
Unsolicited
Remote Peer Deletion Status
: No
Auto-config
: -------------------------------------------------------------------------------TOTAL: 1 Peer(s) Found.
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 10
#
mpls lsr-id 1.1.1.1
mpls
#
mpls ldp
#
mpls ldp remote-peer lsrc
remote-ip 3.3.3.3
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.1 0.0.0.0
network 10.1.1.0 0.0.0.255
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 10 20
#
mpls lsr-id 2.2.2.2
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
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port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 2.2.2.2 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.2 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 20
#
mpls lsr-id 3.3.3.3
mpls
#
mpls ldp
#
mpls ldp remote-peer lsra
remote-ip 1.1.1.1
#
interface Vlanif20
ip address 10.2.1.2 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 3.3.3.3 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.3 0.0.0.0
network 10.2.1.0 0.0.0.255
#
return
4.16.3 Example for Configuring Coexistent Local and Remote
LDP Session
Networking Requirements
In Figure 4-16, LSRA and LSRC are provider edge (PE) devices on the Internet
Protocol/Multiprotocol Label Switching (IP/MPLS) backbone network. MPLS Layer
2 virtual private network (L2VPN) needs to be configured on LSRA and LSRC to
enable communication between VPN sites. A local Label Distribution Protocol
(LDP) session can be configured between the LSRs to establish an LDP label
switched path (LSP) for transmitting the VPN service. In addition, a remote LDP
session can be configured between LSRA and LSRC to implement coexistent local
and remote LDP session.
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Figure 4-16 Networking diagram of coexistent local and remote LDP session
IP/MPLS backbone network
LSRB
/2
/0 /24
E0 .2
G 2.1
.
10 0
2
/2
IF
/0 /24
AN
E0 .1
G 2.1
VL
.
10
10 GE
.3 0/0
.1 /2
.1
/2
4
VL
10 GE
AN
.3 0/0
.1 /1
IF
.2
30
/2
4
Loopback0
2.2.2.2/32
VLANIF10
Loopback0
1.1.1.1/32
GE0/0/1
LSRA 10.1.1.1/24
GE0/0/1
10.1.1.2/24 LSRC
VPN Site
Loopback0
3.3.3.3/32
VPN Site
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
Configuration Roadmap
The configuration roadmap is as follows:
1.
Configure Open Shortest Path First (OSPF) on the LSRs to ensure IP
connectivity on the backbone network.
2.
Configure a local LDP session between the LSRs to transmit the VPN service
over a public network tunnel.
3.
Configure a remote LDP session between LSRA and LSRC to improve the
L2VPN service reliability.
Procedure
Step 1 Create VLANs and VLANIF interfaces on each switch, configure IP addresses for
the VLANIF interfaces, and add physical interfaces to VLANs.
# Configure LSRA. The configurations on LSRB and LSRC are similar to the
configuration on LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 0
[LSRA-LoopBack0] ip address 1.1.1.1 32
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[LSRA-LoopBack0] quit
[LSRA] vlan batch 10 30
[LSRA] interface vlanif 10
[LSRA-Vlanif10] ip address 10.1.1.1 24
[LSRA-Vlanif10] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface vlanif 30
[LSRA-Vlanif30] ip address 10.3.1.1 24
[LSRA-Vlanif30] quit
[LSRA] interface gigabitethernet 0/0/2
[LSRA-GigabitEthernet0/0/2] port link-type trunk
[LSRA-GigabitEthernet0/0/2] port trunk allow-pass vlan 30
[LSRA-GigabitEthernet0/0/2] quit
Step 2 Configure OSPF to advertise the network segments that the interfaces are
connected to and the host route of the LSR ID.
# Configure LSRA.
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0]
[LSRA-ospf-1-area-0.0.0.0]
[LSRA-ospf-1-area-0.0.0.0]
[LSRA-ospf-1-area-0.0.0.0]
[LSRA-ospf-1] quit
network 1.1.1.1 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.3.1.0 0.0.0.255
quit
# Configure LSRB.
[LSRB] ospf 1
[LSRB-ospf-1] area 0
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1] quit
network 2.2.2.2 0.0.0.0
network 10.3.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
quit
# Configure LSRC.
[LSRC] ospf 1
[LSRC-ospf-1] area 0
[LSRC-ospf-1-area-0.0.0.0]
[LSRC-ospf-1-area-0.0.0.0]
[LSRC-ospf-1-area-0.0.0.0]
[LSRC-ospf-1-area-0.0.0.0]
[LSRC-ospf-1] quit
network 3.3.3.3 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
quit
# After the configuration is complete, run the display ip routing-table command
on each node. You can see that nodes learn routes from each other.
Step 3 Enable MPLS and MPLS LDP globally on each LSR.
# Configure LSRA.
[LSRA] mpls lsr-id 1.1.1.1
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
# Configure LSRB.
[LSRB] mpls lsr-id 2.2.2.2
[LSRB] mpls
[LSRB-mpls] quit
[LSRB] mpls ldp
[LSRB-mpls-ldp] quit
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4 MPLS LDP Configuration
# Configure LSRC.
[LSRC] mpls lsr-id 3.3.3.3
[LSRC] mpls
[LSRC-mpls] quit
[LSRC] mpls ldp
[LSRC-mpls-ldp] quit
Step 4 Enable MPLS and MPLS LDP on VLANIF interfaces of each LSR.
# Configure LSRA.
[LSRA] interface vlanif 10
[LSRA-Vlanif10] mpls
[LSRA-Vlanif10] mpls ldp
[LSRA-Vlanif10] quit
[LSRA] interface vlanif 30
[LSRA-Vlanif30] mpls
[LSRA-Vlanif30] mpls ldp
[LSRA-Vlanif30] quit
# Configure LSRB.
[LSRB] interface vlanif 30
[LSRB-Vlanif30] mpls
[LSRB-Vlanif30] mpls ldp
[LSRB-Vlanif30] quit
[LSRB] interface vlanif 20
[LSRB-Vlanif20] mpls
[LSRB-Vlanif20] mpls ldp
[LSRB-Vlanif20] quit
# Configure LSRC.
[LSRC] interface vlanif 10
[LSRC-Vlanif10] mpls
[LSRC-Vlanif10] mpls ldp
[LSRC-Vlanif10] quit
[LSRC] interface vlanif 20
[LSRC-Vlanif20] mpls
[LSRC-Vlanif20] mpls ldp
[LSRC-Vlanif20] quit
Step 5 Specify a remote peer and its IP address on LSRA and LSRC.
# Configure LSRA.
[LSRA] mpls ldp remote-peer LSRC
[LSRA-mpls-ldp-remote-lsrc] remote-ip 3.3.3.3
[LSRA-mpls-ldp-remote-lsrc] quit
# Configure LSRC.
[LSRC] mpls ldp remote-peer LSRA
[LSRC-mpls-ldp-remote-lsra] remote-ip 1.1.1.1
[LSRC-mpls-ldp-remote-lsra] quit
Step 6 Disable STP on each LSR.
# Configure LSRA. The configurations on LSRB and LSRC are similar to the
configuration on LSRA, and are not mentioned here.
<LSRA> system-view
[HUAWEI] stp disable
Step 7 Verify the configuration.
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4 MPLS LDP Configuration
# After the configuration is complete, run the display mpls ldp adjacency
command on LSRA and LSRC. You can see that both a local adjacency and a
remote adjacency are established between LSRA and LSRC.
The command output on LSRA is provided as an example:
[LSRA] display mpls ldp adjacency
LDP Adjacency Information in Public Network
Codes: R: Remote Adjacency, L: Local Adjacency
A '*' before an adjacency means the adjacency is being deleted.
-----------------------------------------------------------------------------SN SourceAddr
PeerID
VrfID AdjAge(DDDD:HH:MM) RcvdHello Type
-----------------------------------------------------------------------------1 10.1.1.2
3.3.3.3
0
0000:00:16
195
L
2 10.3.1.2
2.2.2.2
0
0000:00:03
40
L
3 3.3.3.3
3.3.3.3
0
0000:00:03
18
R
-----------------------------------------------------------------------------TOTAL: 3 Record(s) found.
# Run the display mpls ldp session statistics command on LSRA and LSRC. You
can see that a coexistent local and remote LDP session is displayed on LSRA and
LSRC.
The command output on LSRA is provided as an example:
[LSRA] display mpls ldp session statistics
LDP Session Statistics Information
-----------------------------------------------------------SessionType
Local Remote Local&Remote Total
-----------------------------------------------------------Not Operational
0
0
0
0
Operational
1
0
1
2
-----------------------------------------------------------SessionStatistics 1
0
1
2
------------------------------------------------------------
Run the display mpls ldp lsp command on LSRA. You can see that the outbound
interface on the LSP between LSRA and LSRC is VLANIF 10.
[LSRA] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.1/32
3/NULL
3.3.3.3
127.0.0.1
InLoop0
1.1.1.1/32
3/NULL
2.2.2.2
127.0.0.1
InLoop0
*1.1.1.1/32
Liberal/1025
DS/3.3.3.3
*1.1.1.1/32
Liberal/1025
DS/2.2.2.2
2.2.2.2/32
NULL/3
10.3.1.2
Vlanif30
2.2.2.2/32
1025/3
2.2.2.2
10.3.1.2
Vlanif30
2.2.2.2/32
1025/3
3.3.3.3
10.3.1.2
Vlanif30
*2.2.2.2/32
Liberal/1024
DS/3.3.3.3
3.3.3.3/32
NULL/3
10.1.1.2
Vlanif10
3.3.3.3/32
1024/3
3.3.3.3
10.1.1.2
Vlanif10
3.3.3.3/32
1024/3
2.2.2.2
10.1.1.2
Vlanif10
*3.3.3.3/32
Liberal/1024
DS/2.2.2.2
------------------------------------------------------------------------------TOTAL: 8 Normal LSP(s) Found.
TOTAL: 4 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
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A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
After you shut down GigabitEthernet0/0/1 on LSRA, the directly connected
physical link between LSRA and LSRC fails. The local adjacency between LSRA and
LSRC goes Down, but they are still reachable through LSRB. The remote adjacency
remains Up, the session type changes to remote. Since the session is still Up,
L2VPN is unaware of the session type change and does not delete the session. This
avoids the neighbor disconnection and recovery process and therefore reduces the
service interruption time.
The command output on LSRA is provided as an example:
[LSRA] display mpls ldp adjacency
LDP Adjacency Information in Public Network
Codes: R: Remote Adjacency, L: Local Adjacency
A '*' before an adjacency means the adjacency is being deleted.
-----------------------------------------------------------------------------SN SourceAddr
PeerID
VrfID AdjAge(DDDD:HH:MM) RcvdHello Type
-----------------------------------------------------------------------------1 10.3.1.2
2.2.2.2
0
0000:00:03
43
L
2 3.3.3.3
3.3.3.3
0
0000:00:02
11
R
-----------------------------------------------------------------------------TOTAL: 2 Record(s) found.
[LSRA] display mpls ldp session statistics
LDP Session Statistics Information
-----------------------------------------------------------SessionType
Local Remote Local&Remote Total
-----------------------------------------------------------Not Operational
0
0
0
0
Operational
1
1
0
2
-----------------------------------------------------------SessionStatistics 1
1
0
2
------------------------------------------------------------
Run the display mpls ldp lsp command on LSRA again. You can see that the
outbound interface on the LSP between LSRA and LSRC changes to VLANIF 30.
[LSRA] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.1/32
3/NULL
3.3.3.3
127.0.0.1
InLoop0
1.1.1.1/32
3/NULL
2.2.2.2
127.0.0.1
InLoop0
*1.1.1.1/32
Liberal/1025
DS/3.3.3.3
*1.1.1.1/32
Liberal/1025
DS/2.2.2.2
2.2.2.2/32
NULL/3
10.3.1.2
Vlanif30
2.2.2.2/32
1025/3
2.2.2.2
10.3.1.2
Vlanif30
2.2.2.2/32
1025/3
3.3.3.3
10.3.1.2
Vlanif30
*2.2.2.2/32
Liberal/1024
DS/3.3.3.3
3.3.3.3/32
NULL/1024
10.3.1.2
Vlanif30
3.3.3.3/32
1024/1024
3.3.3.3
10.3.1.2
Vlanif30
3.3.3.3/32
1024/1024
2.2.2.2
10.3.1.2
Vlanif30
*3.3.3.3/32
Liberal/3
DS/3.3.3.3
------------------------------------------------------------------------------TOTAL: 8 Normal LSP(s) Found.
TOTAL: 4 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
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A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
After you run the undo shutdown command to enable GigabitEthernet0/0/1 on
LSRA, the directly connected physical link between LSRA and LSRC recovers. The
L2VPN service will automatically switch back to the shortest path (local
adjacency). Run the display mpls ldp lsp command on LSRA. You can see that the
outbound interface on the LSP between LSRA and LSRC changes to VLANIF 10.
[LSRA] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.1/32
3/NULL
3.3.3.3
127.0.0.1
InLoop0
1.1.1.1/32
3/NULL
2.2.2.2
127.0.0.1
InLoop0
*1.1.1.1/32
Liberal/1025
DS/3.3.3.3
*1.1.1.1/32
Liberal/1025
DS/2.2.2.2
2.2.2.2/32
NULL/3
10.3.1.2
Vlanif30
2.2.2.2/32
1025/3
2.2.2.2
10.3.1.2
Vlanif30
2.2.2.2/32
1025/3
3.3.3.3
10.3.1.2
Vlanif30
*2.2.2.2/32
Liberal/1024
DS/3.3.3.3
3.3.3.3/32
NULL/3
10.1.1.2
Vlanif10
3.3.3.3/32
1024/3
3.3.3.3
10.1.1.2
Vlanif10
3.3.3.3/32
1024/3
2.2.2.2
10.1.1.2
Vlanif10
*3.3.3.3/32
Liberal/1024
DS/2.2.2.2
------------------------------------------------------------------------------TOTAL: 8 Normal LSP(s) Found.
TOTAL: 4 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 10 30
#
stp disable
#
mpls lsr-id 1.1.1.1
mpls
#
mpls ldp
#
mpls ldp remote-peer lsrc
remote-ip 3.3.3.3
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
mpls
mpls ldp
#
interface Vlanif30
ip address 10.3.1.1 255.255.255.0
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mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.1 0.0.0.0
network 10.3.1.0 0.0.0.255
network 10.1.1.0 0.0.0.255
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 20 30
#
stp disable
#
mpls lsr-id 2.2.2.2
mpls
#
mpls ldp
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
mpls
mpls ldp
#
interface Vlanif30
ip address 10.3.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 2.2.2.2 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.2 0.0.0.0
network 10.3.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 10 20
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#
stp disable
#
mpls lsr-id 3.3.3.3
mpls
#
mpls ldp
#
mpls ldp remote-peer lsra
remote-ip 1.1.1.1
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif20
ip address 10.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 3.3.3.3 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.3 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
#
return
4.16.4 Example for Configuring Automatic Triggering of a
Request for a Label Mapping Message in DoD Mode
Networking Requirements
As shown in Figure 4-17, LSRA and LSRD are edge devices of the IP/MPLS
backbone network and have low performance. MPLS L2VPN services need to be
deployed on LSRA and LSRD to connect VPN sites at Layer 2. Because the network
scale is large (this example provides two devices on intermediate nodes), burden
on edge devices needs to be reduced.
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Figure 4-17 Example for configuring automatic triggering of a request for a Label
Mapping message in DoD mode
IP/MPLS backbone network
Loopback0
Loopback0
Loopback0
Loopback0
3.3.3.3/32
4.4.4.4/32
2.2.2.2/32
1.1.1.1/32
GE0/0/1
GE0/0/2
GE0/0/2
VLANIF10
VLANIF20
VLANIF30
10.1.1.1/24
10.1.2.1/24
10.1.3.1/24
GE0/0/1
GE0/0/1
GE0/0/1
VLANIF30
VLANIF10
VLANIF20
LSRC
LSRA
LSRB
LSRD
10.1.3.2/24
10.1.1.2/24
10.1.2.2/24
VPN Site
VPN Site
Configuration Roadmap
To meet the preceding requirements, configure label mapping message in DoD
mode. The configuration roadmap is as follows:
1.
Configure local LDP sessions to establish LDP LSPs to transmit L2VPN services.
2.
Configured remote LDP sessions to exchange VC labels so that PWs are set
up.
3.
To reduce the burden of edge devices, configure the default static route with
the next hop address as the neighbor on the edge device.
4.
The label advertisement mode is set up DoD to reduce unnecessary MPLS
entries.
5.
Configure automatic triggering of a request for a Label Mapping message in
DoD mode so that LDP LSPs can be set up.
Procedure
Step 1 Configure IP addresses for interfaces on each node and configure the loopback
addresses that are used as LSR IDs.
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 0
[LSRA-LoopBack0] ip address 1.1.1.1 32
[LSRA-LoopBack0] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] vlan 10
[LSRA-vlan10] quit
[LSRA] interface vlanif 10
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[LSRA-Vlanif10] ip address 10.1.1.1 24
[LSRA-Vlanif10] quit
Step 2 Configure basic IS-IS functions for backbone devices. Configure static routes for
PEs and their neighbors.
# Configure basic IS-IS functions for LSRB and import a static route.
[LSRB] isis 1
[LSRB-isis-1] network-entity 10.0000.0000.0001.00
[LSRB-isis-1] import-route static
[LSRB-isis-1] quit
[LSRB] interface vlanif 20
[LSRB-Vlanif20] isis enable 1
[LSRB-Vlanif20] quit
[LSRB] interface loopback 0
[LSRB-LoopBack0] isis enable 1
[LSRB-LoopBack0] quit
# Configure basic IS-IS functions for LSRC and import a static route.
[LSRC] isis 1
[LSRC-isis-1] network-entity 10.0000.0000.0002.00
[LSRC-isis-1] import-route static
[LSRC-isis-1] quit
[LSRC] interface vlanif 20
[LSRC-Vlanif20] isis enable 1
[LSRC-Vlanif20] quit
[LSRC] interface loopback 0
[LSRC-LoopBack0] isis enable 1
[LSRC-LoopBack0] quit
# Configure a default route whose next hop IP address is 10.1.1.2 on LSRA.
[LSRA] ip route-static 0.0.0.0 0.0.0.0 10.1.1.2
# On LSRB, configure a static route to LSRA.
[LSRB] ip route-static 1.1.1.1 255.255.255.255 10.1.1.1
# On LSRC, configure a static route to LSRD.
[LSRC] ip route-static 4.4.4.4 255.255.255.255 10.1.3.2
# Configure a default route whose next hop IP address is 10.1.3.1 on LSRD.
[LSRD] ip route-static 0.0.0.0 0.0.0.0 10.1.3.1
# Run the display ip routing-table command on LSRA to view the configure
default route.
[LSRA] display ip routing-table
Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------Routing Tables: Public
Destinations : 6
Routes : 6
Destination/Mask
Proto Pre Cost
0.0.0.0/0 Static 60 0
1.1.1.1/32 Direct 0 0
10.1.1.0/24 Direct 0 0
10.1.1.1/32 Direct 0 0
127.0.0.0/8 Direct 0 0
127.0.0.1/32 Direct 0 0
RD
D
D
D
D
D
Flags NextHop
10.1.1.2
127.0.0.1
10.1.1.1
127.0.0.1
127.0.0.1
127.0.0.1
Interface
Vlanif10
LoopBack0
Vlanif10
Vlanif10
InLoopBack0
InLoopBack0
# Run the display ip routing-table command on LSRB to view the route to LSRA.
[LSRB] display ip routing-table
Route Flags: R - relay, D - download to fib
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-----------------------------------------------------------------------------Routing Tables: Public
Destinations : 10
Routes : 10
Destination/Mask
Proto
1.1.1.1/32 Static 60
2.2.2.2/32 Direct 0
3.3.3.3/32 ISIS-L1 15
4.4.4.4/32 ISIS-L2 15
10.1.1.0/24 Direct 0
10.1.1.2/32 Direct 0
10.1.2.0/24 Direct 0
10.1.2.1/32 Direct 0
127.0.0.0/8 Direct 0
127.0.0.1/32 Direct 0
Pre Cost
0
0
10
74
0
0
0
0
0
0
Flags NextHop
RD
D
D
D
D
D
D
D
D
D
10.1.1.1
127.0.0.1
10.1.2.2
10.1.2.2
10.1.1.2
127.0.0.1
10.1.2.1
127.0.0.1
127.0.0.1
127.0.0.1
Interface
Vlanif10
LoopBack0
Vlanif20
Vlanif20
Vlanif10
Vlanif10
Vlanif20
Vlanif20
InLoopBack0
InLoopBack0
Step 3 Enable MPLS and MPLS LDP on each node globally and on the interfaces.
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] mpls lsr-id 1.1.1.1
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
[LSRA] interface vlanif 10
[LSRA-Vlanif10] mpls
[LSRA-Vlanif10] mpls ldp
[LSRA-Vlanif10] quit
Step 4 Configure the label advertisement mode as DoD.
# Configure LSRA.
[LSRA] interface Vlanif 10
[LSRA-Vlanif10] mpls ldp advertisement dod
Warning: All the related sessions will be deleted if the operation is performed!Continue? (y/n)y
[LSRA-Vlanif10] quit
# Configure LSRB.
[LSRB] interface vlanif 10
[LSRB-Vlanif10] mpls ldp advertisement dod
Warning: All the related sessions will be deleted if the operation is performed!Continue? (y/n)y
[LSRB-Vlanif10] quit
# Configure LSRC.
[LSRC] interface vlanif 30
[LSRC-Vlanif30] mpls ldp advertisement dod
Warning: All the related sessions will be deleted if the operation is performed!Continue? (y/n)y
[LSRC-Vlanif30] quit
# Configure LSRD.
[LSRD] interface vlanif 30
[LSRD-Vlanif30] mpls ldp advertisement dod
Warning: All the related sessions will be deleted if the operation is performed!Continue? (y/n)y
[LSRD-Vlanif30] quit
Step 5 Configure LDP extensions for inter-area LSPs.
# Run the longest-match command on LSRA to configure LDP to search for a
route according to the longest match rule to establish an inter-area LDP LSP.
[LSRA] mpls ldp
[LSRA-mpls-ldp] longest-match
[LSRA-mpls-ldp] quit
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# Run the longest-match command on LSRD to configure LDP to search for a
route according to the longest match rule to establish an inter-area LDP LSP.
[LSRD] mpls ldp
[LSRD-mpls-ldp] longest-match
[LSRD-mpls-ldp] quit
Step 6 Configure a remote LDP session and enable LDP to automatically trigger a request
for a Label Mapping message in DoD mode.
# Configure LSRA.
[LSRA] mpls ldp remote-peer lsrd
[LSRA-mpls-ldp-remote-lsrd] remote-ip 4.4.4.4
[LSRA-mpls-ldp-remote-lsrd] remote-ip auto-dod-request
[LSRA-mpls-ldp-remote-lsrd] quit
# Configure LSRD.
[LSRD] mpls ldp remote-peer lsra
[LSRD-mpls-ldp-remote-lsra] remote-ip 1.1.1.1
[LSRD-mpls-ldp-remote-lsra] remote-ip auto-dod-request
[LSRD-mpls-ldp-remote-lsra] quit
Step 7 Verify the configuration.
# After the configuration is complete, run the display ip routing-table 4.4.4.4
command on LSRA to view route information.
[LSRA] display ip routing-table 4.4.4.4
Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------Routing Table : Public
Summary Count : 1
Destination/Mask Proto Pre Cost
Flags NextHop
Interface
0.0.0.0/0 Static 60 0
RD 10.1.1.2
Vlanif10
The command output shows that only a default route exists in the routing table
and the route 4.4.4.4 does not exist.
# Run the display mpls ldp lsp command on LSRA to view information about the
established LSP.
[LSRA] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.1/32
3/NULL
4.4.4.4
127.0.0.1
InLoop0
4.4.4.4/32
NULL/1026
10.1.1.2
Vlanif10
------------------------------------------------------------------------------TOTAL: 1 Normal LSP(s) Found.
TOTAL: 0 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
The command output shows that the LSP with the destination address of 4.4.4.4 is
established. LSRA has obtained a Label Mapping message of 4.4.4.4 from LSRB to
establish an LSP.
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[LSRA] display tunnel-info all
* -> Allocated VC Token
Tunnel ID
Type
Destination
Token
---------------------------------------------------------------------0x10000001
lsp
4.4.4.4
0
The command output shows that an LSP between LSRA and LSRD is established.
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 10
#
mpls lsr-id 1.1.1.1
mpls
#
mpls ldp
longest-match
#
mpls ldp remote-peer lsrd
remote-ip 4.4.4.4
remote-ip auto-dod-request
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
mpls
mpls ldp
mpls ldp advertisement dod
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
#
ip route-static 0.0.0.0 0.0.0.0 10.1.1.2
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 10 20
#
mpls lsr-id 2.2.2.2
mpls
#
mpls ldp
#
isis 1
network-entity 10.0000.0000.0001.00
import-route static
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
mpls
mpls ldp
mpls ldp advertisement dod
#
interface Vlanif20
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4 MPLS LDP Configuration
ip address 10.1.2.1 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 2.2.2.2 255.255.255.255
isis enable 1
#
ip route-static 1.1.1.1 255.255.255.255 10.1.1.1
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 20 30
#
mpls lsr-id 3.3.3.3
mpls
#
mpls ldp
#
isis 1
network-entity 10.0000.0000.0002.00
import-route static
#
interface Vlanif20
ip address 10.1.2.2 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface Vlanif30
ip address 10.1.3.1 255.255.255.0
mpls
mpls ldp
mpls ldp advertisement dod
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack0
ip address 3.3.3.3 255.255.255.255
isis enable 1
#
ip route-static 4.4.4.4 255.255.255.255 10.1.3.2
#
return
●
LSRD configuration file
#
sysname LSRD
#
vlan batch 30
#
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4 MPLS LDP Configuration
mpls lsr-id 4.4.4.4
mpls
#
mpls ldp
longest-match
#
mpls ldp remote-peer lsra
remote-ip 1.1.1.1
remote-ip auto-dod-request
#
interface Vlanif30
ip address 10.1.3.2 255.255.255.0
mpls
mpls ldp
mpls ldp advertisement dod
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack0
ip address 4.4.4.4 255.255.255.255
#
ip route-static 0.0.0.0 0.0.0.0 10.1.3.1
#
return
4.16.5 Example for Configuring a Policy for Triggering LDP LSP
Establishment on the Ingress and Egress Nodes
Networking Requirements
As shown in Figure 4-18, LSRA and LSRD are edge devices of the MPLS backbone
network and have low performance. After MPLS LDP is enabled on each LSR
interface, LDP LSPs are set up automatically. Because the network scale is large
(this example provides two devices on intermediate nodes), many unnecessary
LSPs are set up, wasting resources. The number of LSPs established on edge
devices needs to be reduced so that the burden of edge devices is reduced.
Figure 4-18 Networking diagram for configuring a policy for triggering LDP LSP
establishment
Loopback0
2.2.2.9/32
Loopback0
3.3.3.9/32
GE0/0/2
GE0/0/1
10.2.1.1/24 10.2.1.2/24
LSRB
VLANIF20 VLANIF20
GE0/0/1
10.1.1.2/24
VLANIF10
VLANIF30
GE0/0/1
10.1.1.1/24
VLANIF10
VLANIF30
GE0/0/2
10.3.1.1/24
GE0/0/1
10.3.1.2/24
LSRD
LSRA
Loopback0
1.1.1.9/32
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LSRC
Loopback0
4.4.4.9/32
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4 MPLS LDP Configuration
Configuration Roadmap
You can configure a policy for triggering LDP LSP setup to meet the requirement.
The configuration roadmap is as follows:
1.
Configure OSPF between the LSRs to implement IP connectivity on the
backbone network.
2.
Configure local LDP sessions on LSRs so that LDP LSPs can be set up.
3.
Configure a policy for triggering LDP LSP setup on LSRA and LSRD to reduce
the number of LSPs on edge devices so that the burden of edge devices is
reduced.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 0
[LSRA-LoopBack0] ip address 1.1.1.9 32
[LSRA-LoopBack0] quit
[LSRA] vlan batch 10
[LSRA] interface vlanif 10
[LSRA-Vlanif10] ip address 10.1.1.1 24
[LSRA-Vlanif10] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
Step 3 Configure basic MPLS and MPLS LDP functions on the nodes and interfaces
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
[LSRA] interface vlanif 10
[LSRA-Vlanif10] mpls
[LSRA-Vlanif10] mpls ldp
[LSRA-Vlanif10] quit
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4 MPLS LDP Configuration
# Run the display mpls lsp command on each node to view the establishment of
the LDP LSPs. LSRA is used as an example.
[LSRA] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
1.1.1.9/32
3/NULL
-/2.2.2.9/32
NULL/3
-/Vlanif10
2.2.2.9/32
1024/3
-/Vlanif10
3.3.3.9/32
NULL/1025
-/Vlanif10
3.3.3.9/32
1022/1025
-/Vlanif10
4.4.4.9/32
NULL/4118
-/Vlanif10
4.4.4.9/32
4105/4118
-/Vlanif10
Step 4 Configure an IP prefix list to filter routes.
# Configure an IP prefix list on LSRA that allows only 1.1.1.9/32 and 4.4.4.9/32 for
LSP setup.
[LSRA] ip ip-prefix FilterOnIngress permit 1.1.1.9 32
[LSRA] ip ip-prefix FilterOnIngress permit 4.4.4.9 32
[LSRA] mpls
[LSRA-mpls] lsp-trigger ip-prefix FilterOnIngress
[LSRA-mpls] quit
# Configure an IP prefix list on LSRD that allows only 1.1.1.9/32 and 4.4.4.9/32 for
LSP setup.
[LSRD] ip ip-prefix FilterOnEgress permit 1.1.1.9 32
[LSRD] ip ip-prefix FilterOnEgress permit 4.4.4.9 32
[LSRD] mpls
[LSRD-mpls] lsp-trigger ip-prefix FilterOnEgress
[LSRD-mpls] quit
Step 5 Verify the configuration.
# After the configuration is complete, run the display mpls lsp command on LSRA
and LSRD to view LDP LSP establishment.
[LSRA] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
1.1.1.9/32
3/NULL
-/2.2.2.9/32
1024/3
-/Vlanif10
3.3.3.9/32
1022/1025
-/Vlanif10
4.4.4.9/32
NULL/4118
-/Vlanif10
4.4.4.9/32
4105/4118
-/Vlanif10
After the policy is configured, there are only LDP LSPs to the destination 1.1.1.9/32
and 4.4.4.9/32 with LSRA as the ingress node and other LDP LSPs that do not use
LSRA as the ingress node.
[LSRD] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
1.1.1.9/32
NULL/4110
-/Vlanif30
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1.1.1.9/32
2.2.2.9/32
3.3.3.9/32
4.4.4.9/32
4 MPLS LDP Configuration
4100/4110
-/Vlanif30
1023/1028
-/Vlanif30
1027/3
-/Vlanif30
3/NULL
-/-
After the policy is configured, there are only LDP LSPs to the destination 1.1.1.9/32
and 4.4.4.9/32 with LSRD as the ingress node and other LDP LSPs that do not use
LSRD as the ingress node.
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 10
#
mpls lsr-id 1.1.1.9
mpls
lsp-trigger ip-prefix FilterOnIngress
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface LoopBack0
ip address 1.1.1.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 10.1.1.0 0.0.0.255
#
ip ip-prefix FilterOnIngress index 10 permit 1.1.1.9 32
ip ip-prefix FilterOnIngress index 20 permit 4.4.4.9 32
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 10 20
#
mpls lsr-id 2.2.2.9
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
mpls
mpls ldp
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4 MPLS LDP Configuration
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 2.2.2.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 20 30
#
mpls lsr-id 3.3.3.9
mpls
#
mpls ldp
#
interface Vlanif20
ip address 10.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif30
ip address 10.3.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack0
ip address 3.3.3.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 10.2.1.0 0.0.0.255
network 10.3.1.0 0.0.0.255
#
return
●
LSRD configuration file
#
sysname LSRD
#
vlan batch 30
#
mpls lsr-id 4.4.4.9
mpls
lsp-trigger ip-prefix FilterOnEgress
#
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4 MPLS LDP Configuration
mpls ldp
#
interface Vlanif30
ip address 10.3.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack0
ip address 4.4.4.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 4.4.4.9 0.0.0.0
network 10.3.1.0 0.0.0.255
#
ip ip-prefix FilterOnEgress index 10 permit 1.1.1.9 32
ip ip-prefix FilterOnEgress index 20 permit 4.4.4.9 32
#
return
4.16.6 Example for Configuring a Policy for Triggering LDP LSP
Establishment on the Transit Node
Networking Requirements
As shown in Figure 4-19, LSRA and LSRD are edge devices of the MPLS backbone
network and have low performance. After MPLS LDP is enabled on each LSR
interface, LDP LSPs are set up automatically. Because the network scale is large
(this example provides two devices on intermediate nodes), many unnecessary
LSPs are set up, wasting resources. The number of LSPs established on edge
devices needs to be reduced so that the burden of edge devices is reduced.
Policies cannot be configured on edge devices.
Figure 4-19 Networking diagram for configuring a policy for triggering LDP LSP
establishment
Loopback0
2.2.2.9/32
Loopback0
3.3.3.9/32
GE0/0/2
GE0/0/1
10.2.1.1/24 10.2.1.2/24
LSRB
VLANIF20 VLANIF20
GE0/0/1
10.1.1.2/24
VLANIF10
VLANIF30
GE0/0/1
10.1.1.1/24
VLANIF10
VLANIF30
GE0/0/2
10.3.1.1/24
GE0/0/1
10.3.1.2/24
LSRD
LSRA
Loopback0
1.1.1.9/32
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LSRC
Loopback0
4.4.4.9/32
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Configuration Guide - MPLS
4 MPLS LDP Configuration
Configuration Roadmap
You can configure a policy for triggering LDP LSP setup to meet the requirement.
The configuration roadmap is as follows:
1.
Configure OSPF between the LSRs to implement IP connectivity on the
backbone network.
2.
Configure local LDP sessions on LSRs so that LDP LSPs can be set up.
3.
Configure a policy for triggering LDP LSP setup on LSRB and LSRC to reduce
the number of LSPs on edge devices so that the burden of edge devices is
reduced.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 0
[LSRA-LoopBack0] ip address 1.1.1.9 32
[LSRA-LoopBack0] quit
[LSRA] vlan batch 10
[LSRA] interface vlanif 10
[LSRA-Vlanif10] ip address 10.1.1.1 24
[LSRA-Vlanif10] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
Step 3 Configure basic MPLS and MPLS LDP functions on the nodes and interfaces
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
[LSRA] interface vlanif 10
[LSRA-Vlanif10] mpls
[LSRA-Vlanif10] mpls ldp
[LSRA-Vlanif10] quit
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4 MPLS LDP Configuration
# Run the display mpls ldp lsp command on each node to view the
establishment of the LDP LSPs. LSRA is used as an example.
[LSRA] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.9/32
3/NULL
2.2.2.9
127.0.0.1
InLoop0
*1.1.1.9/32
Liberal/3
DS/2.2.2.9
2.2.2.9/32
NULL/3
10.1.1.2
Vlanif10
2.2.2.9/32
1024/3
2.2.2.9
10.1.1.2
Vlanif10
3.3.3.9/32
NULL/1025
10.1.1.2
Vlanif10
3.3.3.9/32
1022/1025
2.2.2.9
10.1.1.2
Vlanif10
4.4.4.9/32
NULL/4118
10.1.1.2
Vlanif10
4.4.4.9/32
4105/4118
2.2.2.9
10.1.1.2
Vlanif10
------------------------------------------------------------------------------TOTAL: 7 Normal LSP(s) Found.
TOTAL: 1 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
Step 4 Configure an IP prefix list to filter routes.
# Configure the IP prefix list on transit node LSRB to allow only 1.1.1.9/32 and
4.4.4.9/32 for LSP setup.
[LSRB] ip ip-prefix FilterOnTransit permit 1.1.1.9 32
[LSRB] ip ip-prefix FilterOnTransit permit 4.4.4.9 32
[LSRB] mpls ldp
[LSRB-mpls-ldp] propagate mapping for ip-prefix FilterOnTransit
[LSRB-mpls-ldp] quit
# Configure the IP prefix list on transit node LSRC to allow only 1.1.1.9/32 and
4.4.4.9/32 for LSP setup.
[LSRC] ip ip-prefix FilterOnTransit permit 1.1.1.9 32
[LSRC] ip ip-prefix FilterOnTransit permit 4.4.4.9 32
[LSRC] mpls ldp
[LSRC-mpls-ldp] propagate mapping for ip-prefix FilterOnTransit
[LSRC-mpls-ldp] quit
Step 5 Verify the configuration.
# After the configuration is complete, run the display mpls ldp lsp command on
LSRA and LSRD to view LDP LSP establishment.
[LSRA] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.9/32
3/NULL
2.2.2.9
127.0.0.1
InLoop0
*1.1.1.9/32
Liberal/3
DS/2.2.2.9
2.2.2.9/32
NULL/3
10.1.1.2
Vlanif10
2.2.2.9/32
1024/3
2.2.2.9
10.1.1.2
Vlanif10
4.4.4.9/32
NULL/4118
10.1.1.2
Vlanif10
4.4.4.9/32
4105/4118
2.2.2.9
10.1.1.2
Vlanif10
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------------------------------------------------------------------------------TOTAL: 5 Normal LSP(s) Found.
TOTAL: 1 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
Because the policy for triggering LDP LSP setup is configured on LSRB, the LDP
LSP destined for 3.3.3.9/32 is filtered on LSRA.
[LSRD] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.9/32
NULL/4110
10.3.1.1
Vlanif30
1.1.1.9/32
4100/4110
3.3.3.9
10.3.1.1
Vlanif30
3.3.3.9/32
NULL/3
10.3.1.1
Vlanif30
3.3.3.9/32
1026/3
3.3.3.9
10.3.1.1
Vlanif30
4.4.4.9/32
3/NULL
3.3.3.9
127.0.0.1
InLoop0
*4.4.4.9/32
Liberal/3
DS/3.3.3.9
------------------------------------------------------------------------------TOTAL: 5 Normal LSP(s) Found.
TOTAL: 1 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
Because the policy for triggering LDP LSP setup is configured on LSRC, the LDP
LSP destined for 2.2.2.9/32 is filtered on LSRD.
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 10
#
mpls lsr-id 1.1.1.9
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface LoopBack0
ip address 1.1.1.9 255.255.255.255
#
ospf 1
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4 MPLS LDP Configuration
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 10.1.1.0 0.0.0.255
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 10 20
#
mpls lsr-id 2.2.2.9
mpls
#
mpls ldp
propagate mapping for ip-prefix FilterOnTransit
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 2.2.2.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
#
ip ip-prefix FilterOnTransit index 10 permit 1.1.1.9 32
ip ip-prefix FilterOnTransit index 20 permit 4.4.4.9 32
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 20 30
#
mpls lsr-id 3.3.3.9
mpls
#
mpls ldp
propagate mapping for ip-prefix FilterOnTransit
#
interface Vlanif20
ip address 10.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif30
ip address 10.3.1.1 255.255.255.0
mpls
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mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack0
ip address 3.3.3.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 10.2.1.0 0.0.0.255
network 10.3.1.0 0.0.0.255
#
ip ip-prefix FilterOnTransit index 10 permit 1.1.1.9 32
ip ip-prefix FilterOnTransit index 20 permit 4.4.4.9 32
#
return
●
LSRD configuration file
#
sysname LSRD
#
vlan batch 30
#
mpls lsr-id 4.4.4.9
mpls
#
mpls ldp
#
interface Vlanif30
ip address 10.3.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack0
ip address 4.4.4.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 4.4.4.9 0.0.0.0
network 10.3.1.0 0.0.0.255
#
return
4.16.7 Example for Disabling Devices from Distributing LDP
Labels to Remote Peers
Networking Requirements
As shown in Figure 4-20, PE1, PE2, and PE3 connect to the P of the MPLS
backbone network and IS-IS is used. Public LSPs are used to transmit L2VPN
services. PE1 establishes remote LDP sessions with PE2 and PE3 to exchange
private labels. Dynamic Pseudo Wires (PWs) are set up between PE1 and PE2 and
between PE1 and PE3.
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On an MPLS network, LDP transmits private network label and distributes
common LDP labels to remote peers. Multiple remote LDP peers on the network
lead to a large number of null labels, which occupies many system resources. The
label distribution to remote LDP peers needs to be controlled to save system
resources.
Figure 4-20 Networking diagram for disabling devices from distributing LDP labels
to remote peers
Loopback 0
5.5.5.5/32
Loopback 0
1.1.1.1/32
20 GE
VL .1. 0/0
AN 1.1 /3
IF /24
20
20 GE
VL .1. 0/0
AN 1.2 /1
IF /24
20
PE2
GE0/0/1
40.1.1.2/24
VLANIF10
P
/1
/0 /24
E0 .2 0
G 1.1 IF3
. N
30 LA
V
/2
/0 /24
E0 .1 0
G 1.1 IF3
. N
30 LA
V
GE0/0/1
PE1 40.1.1.1/24
VLANIF10
Loopback 0
2.2.2.2/32
PE3
Loopback 0
4.4.4.4/32
Configuration Roadmap
To meet the preceding requirements, disable devices from distributing LDP labels
to remote peers. The configuration roadmap is as follows:
1.
Configure IS-IS between on PEs and P to implement IP connectivity on the
backbone network.
2.
Configure local LDP sessions on PEs and P so that public LSPs can be set up to
transmit L2VPN services.
3.
Configure remote LDP sessions on PEs to exchange private labels so that
dynamic PWs are set up.
4.
Disable PEs from allocating labels to remote peers so that PE1 cannot allocate
LDP labels to PE2 and PE3. This setting saves system resources.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
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# Configure PE1. The configurations of P, PE2, and PE3 are similar to the
configuration of PE1, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname PE1
[PE1] interface loopback 0
[PE1-LoopBack0] ip address 1.1.1.1 32
[PE1-LoopBack0] quit
[PE1] vlan batch 10
[PE1] interface vlanif 10
[PE1-Vlanif10] ip address 40.1.1.1 24
[PE1-Vlanif10] quit
[PE1] interface gigabitethernet 0/0/1
[PE1-GigabitEthernet0/0/1] port link-type trunk
[PE1-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[PE1-GigabitEthernet0/0/1] quit
Step 2 Configure IS-IS to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure PE1.
[PE1] isis 1
[PE1-isis-1] is-level level-2
[PE1-isis-1] network-entity 86.4501.0010.0100.0001.00
[PE1-isis-1] quit
[PE1] interface vlanif 10
[PE1-Vlanif10] isis enable 1
[PE1-Vlanif10] quit
[PE1] interface loopback 0
[PE1-LoopBack0] isis enable 1
[PE1-LoopBack0] quit
# Configure P.
[P] isis 1
[P-isis-1] is-level level-2
[P-isis-1] network-entity 86.4501.0030.0300.0003.00
[P-isis-1] quit
[P] interface vlanif 10
[P-Vlanif10] isis enable 1
[P-Vlanif10] quit
[P] interface vlanif 20
[P-Vlanif20] isis enable 1
[P-Vlanif20] quit
[P] interface vlanif 30
[P-Vlanif30] isis enable 1
[P-Vlanif30] quit
[P] interface loopback 0
[P-LoopBack0] isis enable 1
[P-LoopBack0] quit
# Configure PE2.
[PE2] isis 1
[PE2-isis-1] is-level level-2
[PE2-isis-1] network-entity 86.4501.0050.0500.0005.00
[PE2-isis-1] quit
[PE2] interface vlanif 20
[PE2-Vlanif20] isis enable 1
[PE2-Vlanif20] quit
[PE2] interface loopback 0
[PE2-LoopBack0] isis enable 1
[PE2-LoopBack0] quit
# Configure PE3.
[PE3] isis 1
[PE3-isis-1] is-level level-2
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[PE3-isis-1] network-entity 86.4501.0040.0400.0004.00
[PE3-isis-1] quit
[PE3] interface vlanif 30
[PE3-Vlanif30] isis enable 1
[PE3-Vlanif30] quit
[PE3] interface loopback 0
[PE3-LoopBack0] isis enable 1
[PE3-LoopBack0] quit
Step 3 Configure local LDP sessions.
# Configure PE1.
[PE1] mpls lsr-id 1.1.1.1
[PE1] mpls
[PE1-mpls] quit
[PE1] mpls ldp
[PE1-mpls-ldp] quit
[PE1] interface vlanif 10
[PE1-Vlanif10] mpls
[PE1-Vlanif10] mpls ldp
[PE1-Vlanif10] quit
# Configure P.
[P] mpls lsr-id 2.2.2.2
[P] mpls
[P-mpls] quit
[P] mpls ldp
[P-mpls-ldp] quit
[P] interface vlanif 10
[P-Vlanif10] mpls
[P-Vlanif10] mpls ldp
[P-Vlanif10] quit
[P] interface vlanif 20
[P-Vlanif20] mpls
[P-Vlanif20] mpls ldp
[P-Vlanif20] quit
[P] interface vlanif 30
[P-Vlanif30] mpls
[P-Vlanif30] mpls ldp
[P-Vlanif30] quit
# Configure PE2.
[PE2] mpls lsr-id 5.5.5.5
[PE2] mpls
[PE2-mpls] quit
[PE2] mpls ldp
[PE2-mpls-ldp] quit
[PE2] interface vlanif 20
[PE2-Vlanif20] mpls
[PE2-Vlanif20] mpls ldp
[PE2-Vlanif20] quit
# Configure PE3.
[PE3] mpls lsr-id 4.4.4.4
[PE3] mpls
[PE3-mpls] quit
[PE3] mpls ldp
[PE3-mpls-ldp] quit
[PE3] interface vlanif 30
[PE3-Vlanif30] mpls
[PE3-Vlanif30] mpls ldp
[PE3-Vlanif30] quit
After the configuration is complete, LDP sessions and public network LSPs are
established between neighboring nodes. Run the display mpls ldp session
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command on each node. The command output shows that the LDP session status
is Operational. PE1 is used as an example
[PE1] display mpls ldp session
LDP Session(s) in Public Network
Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDDD:HH:MM)
A '*' before a session means the session is being deleted.
-----------------------------------------------------------------------------PeerID
Status
LAM SsnRole SsnAge
KASent/Rcv
-----------------------------------------------------------------------------2.2.2.2:0
Operational DU Passive 0000:00:01 6/6
-----------------------------------------------------------------------------TOTAL: 1 session(s) Found.
Run the display mpls ldp lsp command to check the LSP setup result and label
distribution.
[PE1] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.1/32
3/NULL
2.2.2.2
127.0.0.1
InLoop0
*1.1.1.1/32
Liberal/1025
DS/2.2.2.2
2.2.2.2/32
NULL/3
40.1.1.2
Vlanif10
2.2.2.2/32
1024/3
2.2.2.2
40.1.1.2
Vlanif10
4.4.4.4/32
NULL/1024
40.1.1.2
Vlanif10
4.4.4.4/32
1025/1024
2.2.2.2
40.1.1.2
Vlanif10
5.5.5.5/32
NULL/1026
40.1.1.2
Vlanif10
5.5.5.5/32
1022/1026
2.2.2.2
40.1.1.2
Vlanif10
------------------------------------------------------------------------------TOTAL: 7 Normal LSP(s) Found.
TOTAL: 1 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
Step 4 Set up the remote MPLS LDP peer relationship between PEs at both ends of the
PW.
# Configure PE1.
[PE1] mpls ldp remote-peer pe2
[PE1-mpls-ldp-remote-pe2] remote-ip 5.5.5.5
[PE1-mpls-ldp-remote-pe2] quit
[PE1] mpls ldp remote-peer pe3
[PE1-mpls-ldp-remote-pe3] remote-ip 4.4.4.4
[PE1-mpls-ldp-remote-pe3] quit
# Configure PE2.
[PE2] mpls ldp remote-peer pe1
[PE2-mpls-ldp-remote-pe1] remote-ip 1.1.1.1
[PE2-mpls-ldp-remote-pe1] quit
# Configure PE3.
[PE3] mpls ldp remote-peer pe1
[PE3-mpls-ldp-remote-pe1] remote-ip 1.1.1.1
[PE3-mpls-ldp-remote-pe1] quit
After the configuration is complete, remote LDP sessions are established between
neighboring PEs. Run the display mpls ldp session command on each node. The
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command output shows that the LDP session status is Operational. PE1 is used as
an example
[PE1] display mpls ldp session
LDP Session(s) in Public Network
Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDDD:HH:MM)
A '*' before a session means the session is being deleted.
-----------------------------------------------------------------------------PeerID
Status
LAM SsnRole SsnAge
KASent/Rcv
-----------------------------------------------------------------------------2.2.2.2:0
Operational DU Passive 0000:00:18 75/75
4.4.4.4:0
Operational DU Passive 0000:00:10 43/43
5.5.5.5:0
Operational DU Passive 0000:00:12 50/50
-----------------------------------------------------------------------------TOTAL: 3 session(s) Found.
Run the display mpls ldp lsp command to view the label distribution. The
command output shows that PEs have distributed liberal labels to their own
remote neighbors. These labels, however, are idle and occupy many system
resources in MPLS L2VPN applications that use PWE3 technology.
[PE1] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.1/32
3/NULL
2.2.2.2
127.0.0.1
InLoop0
1.1.1.1/32
3/NULL
5.5.5.5
127.0.0.1
InLoop0
1.1.1.1/32
3/NULL
4.4.4.4
127.0.0.1
InLoop0
*1.1.1.1/32
Liberal/1025
DS/2.2.2.2
*1.1.1.1/32
Liberal/1024
DS/5.5.5.5
*1.1.1.1/32
Liberal/1025
DS/4.4.4.4
2.2.2.2/32
NULL/3
40.1.1.2
Vlanif10
2.2.2.2/32
1024/3
2.2.2.2
40.1.1.2
Vlanif10
2.2.2.2/32
1024/3
5.5.5.5
40.1.1.2
Vlanif10
2.2.2.2/32
1024/3
4.4.4.4
40.1.1.2
Vlanif10
*2.2.2.2/32
Liberal/1025
DS/5.5.5.5
*2.2.2.2/32
Liberal/1024
DS/4.4.4.4
4.4.4.4/32
NULL/1024
40.1.1.2
Vlanif10
4.4.4.4/32
1025/1024
2.2.2.2
40.1.1.2
Vlanif10
4.4.4.4/32
1025/1024
5.5.5.5
40.1.1.2
Vlanif10
4.4.4.4/32
1025/1024
4.4.4.4
40.1.1.2
Vlanif10
*4.4.4.4/32
Liberal/1026
DS/5.5.5.5
*4.4.4.4/32
Liberal/3
DS/4.4.4.4
5.5.5.5/32
NULL/1026
40.1.1.2
Vlanif10
5.5.5.5/32
1022/1026
2.2.2.2
40.1.1.2
Vlanif10
5.5.5.5/32
1022/1026
5.5.5.5
40.1.1.2
Vlanif10
5.5.5.5/32
1022/1026
4.4.4.4
40.1.1.2
Vlanif10
*5.5.5.5/32
Liberal/3
DS/5.5.5.5
*5.5.5.5/32
Liberal/1026
DS/4.4.4.4
------------------------------------------------------------------------------TOTAL: 15 Normal LSP(s) Found.
TOTAL: 9 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
Step 5 Disable devices from distributing LDP labels to remote peers on PEs at both ends
of a PW.
# Configure PE1.
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[PE1] mpls ldp remote-peer pe2
[PE1-mpls-ldp-remote-pe2] remote-ip 5.5.5.5 pwe3
[PE1-mpls-ldp-remote-pe2] quit
[PE1] mpls ldp remote-peer pe3
[PE1-mpls-ldp-remote-pe3] remote-ip 4.4.4.4 pwe3
[PE1-mpls-ldp-remote-pe3] quit
# Configure PE2.
[PE2] mpls ldp remote-peer pe1
[PE2-mpls-ldp-remote-pe1] remote-ip 1.1.1.1 pwe3
[PE2-mpls-ldp-remote-pe1] quit
# Configure PE3.
[PE3] mpls ldp remote-peer pe1
[PE3-mpls-ldp-remote-pe1] remote-ip 1.1.1.1 pwe3
[PE3-mpls-ldp-remote-pe1] quit
After the configuration is complete, PEs do not distribute labels to remote LDP
peers. Run the display mpls ldp lsp command on each node to view the
established LSP after devices from distributing LDP labels to remote peers is
disabled. PE1 is used as an example.
[PE1] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.1/32
3/NULL
2.2.2.2
127.0.0.1
InLoop0
*1.1.1.1/32
Liberal/1024
DS/2.2.2.2
2.2.2.2/32
NULL/3
40.1.1.2
Vlanif10
2.2.2.2/32
1025/3
2.2.2.2
40.1.1.2
Vlanif10
4.4.4.4/32
NULL/1024
40.1.1.2
Vlanif10
4.4.4.4/32
1025/1024
2.2.2.2
40.1.1.2
Vlanif10
5.5.5.5/32
NULL/1026
40.1.1.2
Vlanif10
5.5.5.5/32
1022/1026
2.2.2.2
40.1.1.2
Vlanif10
------------------------------------------------------------------------------TOTAL: 7 Normal LSP(s) Found.
TOTAL: 1 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
A large number of idle remote labels and LSPs are disabled. The LSPs are
established based on the local LDP sessions.
----End
Configuration Files
●
PE1 configuration file
#
sysname PE1
#
vlan batch 10
#
mpls lsr-id 1.1.1.1
mpls
#
mpls ldp
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#
mpls ldp remote-peer pe2
remote-ip 5.5.5.5 pwe3
#
mpls ldp remote-peer pe3
remote-ip 4.4.4.4 pwe3
#
isis 1
is-level level-2
network-entity 86.4501.0010.0100.0001.00
#
interface Vlanif10
ip address 40.1.1.1 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
isis enable 1
#
return
●
P configuration file
#
sysname P
#
vlan batch 10 20 30
#
mpls lsr-id 2.2.2.2
mpls
#
mpls ldp
#
isis 1
is-level level-2
network-entity 86.4501.0030.0300.0003.00
#
interface Vlanif10
ip address 40.1.1.2 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface Vlanif20
ip address 20.1.1.1 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface Vlanif30
ip address 30.1.1.1 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/3
port link-type trunk
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port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 2.2.2.2 255.255.255.255
isis enable 1
#
return
●
PE2 configuration file
#
sysname PE2
#
vlan batch 20
#
mpls lsr-id 5.5.5.5
mpls
#
mpls ldp
#
mpls ldp remote-peer pe1
remote-ip 1.1.1.1 pwe3
#
isis 1
is-level level-2
network-entity 86.4501.0050.0500.0005.00
#
interface Vlanif20
ip address 20.1.1.2 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 5.5.5.5 255.255.255.255
isis enable 1
#
return
●
PE3 configuration file
#
sysname PE3
#
vlan batch 30
#
mpls lsr-id 4.4.4.4
mpls
#
mpls ldp
#
mpls ldp remote-peer pe1
remote-ip 1.1.1.1 pwe3
#
isis 1
is-level level-2
network-entity 86.4501.0040.0400.0004.00
#
interface Vlanif30
ip address 30.1.1.2 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
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interface LoopBack0
ip address 4.4.4.4 255.255.255.255
isis enable 1
#
return
4.16.8 Example for Configuring Static BFD to Detect LDP LSPs
Networking Requirements
As shown in Figure 4-21, the network topology is simple and stable. PEs and P are
MPLS backbone network devices, and LDP LSPs are set up on the backbone
network to transmit network services.
Network services, such as VoIP, online game, and online video service, have high
requirements for real-timeness. Data loss caused by faulty links will seriously
affect services. It is required that services be fast switched to the backup LSP when
the primary LSP becomes faulty, minimizing packet loss. Static BFD for LDP LSPs is
configured to fast detect LDP LSPs.
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
Figure 4-21 Networking diagram of configuring static BFD for LDP LSPs
Loopback1
2.2.2.2/32
G
10 E0/
/1 4
0
/
.
0/
2
0 /2
VL .1.1/ 2
GE .1.2 10
24
AN
.1
F
G
IF2
Loopback1
/1 4 10 ANI
P1
10 E0/ Loopback1
0
/
L
0
2
0
.
/
2 0 4.4.4.4/32
V
1.1.1.1/32 GE .1
VL .1.2 /1
1
0
.
1
/2
AN
.1
F
Primary LSP
10 ANI
IF2 4
0
VL
VL
0
AN
IF4
Backup LSP
N
PE1 10 GE0 IF30
PE2
/2
A
.3. /0/2
VL E0/0 /24
V
1.1
LA
G .1.2
40
/24
F
I
GE NIF3
0.4
P2
N
1
A
10 0/
0
/2
.3. 0/1
VL
0/0 /24
1.2
E
G .1.1
/24
.4
10
Loopback1
3.3.3.3/32
Configuration Roadmap
The configuration roadmap is as follows:
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4 MPLS LDP Configuration
1.
Configure OSPF between the PEs and P to implement IP connectivity on the
backbone network.
2.
Configure local LDP sessions on PEs and P so that LDP LSPs can be set up to
transmit network services.
3.
Configure static BFD on PEs to fast detect LDP LSPs.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
# Configure PE1. The configurations of P1, P2, and PE2 are similar to the
configuration of PE1, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname PE1
[PE1] interface loopback 1
[PE1-LoopBack1] ip address 1.1.1.1 32
[PE1-LoopBack1] quit
[PE1] vlan batch 10 30
[PE1] interface vlanif 10
[PE1-Vlanif10] ip address 10.1.1.1 24
[PE1-Vlanif10] quit
[PE1] interface vlanif 30
[PE1-Vlanif30] ip address 10.3.1.1 24
[PE1-Vlanif30] quit
[PE1] interface gigabitethernet 0/0/1
[PE1-GigabitEthernet0/0/1] port link-type trunk
[PE1-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[PE1-GigabitEthernet0/0/1] quit
[PE1] interface gigabitethernet 0/0/2
[PE1-GigabitEthernet0/0/2] port link-type trunk
[PE1-GigabitEthernet0/0/2] port trunk allow-pass vlan 30
[PE1-GigabitEthernet0/0/2] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure PE1. The configurations of P1, P2, and PE2 are similar to the
configuration of PE1, and are not mentioned here.
[PE1] ospf 1
[PE1-ospf-1] area 0
[PE1-ospf-1-area-0.0.0.0]
[PE1-ospf-1-area-0.0.0.0]
[PE1-ospf-1-area-0.0.0.0]
[PE1-ospf-1-area-0.0.0.0]
[PE1-ospf-1] quit
network 1.1.1.1 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.3.1.0 0.0.0.255
quit
Step 3 Set the cost of VLANIF 30 on PE1 to 1000.
[PE1] interface vlanif 30
[PE1-Vlanif30] ospf cost 1000
[PE1-Vlanif30] quit
After the configuration is complete, run the display ip routing-table command
on each node. You can see that the nodes learn routes from each other. The
outbound interface of the route from PE1 to PE2 is VLANIF 10.
Step 4 Configure local LDP sessions.
# Configure PE1. The configurations of P1, P2, and PE2 are similar to the
configuration of PE1, and are not mentioned here.
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[PE1] mpls lsr-id 1.1.1.1
[PE1] mpls
[PE1-mpls] quit
[PE1] mpls ldp
[PE1-mpls-ldp] quit
[PE1] interface vlanif 10
[PE1-Vlanif10] mpls
[PE1-Vlanif10] mpls ldp
[PE1-Vlanif10] quit
[PE1] interface vlanif 30
[PE1-Vlanif30] mpls
[PE1-Vlanif30] mpls ldp
[PE1-Vlanif30] quit
# Run the display mpls ldp lsp command. The command output shows that an
LDP LSP destined for 4.4.4.4/32 is set up on PE1.
[PE1] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.1/32
3/NULL
2.2.2.2
127.0.0.1
InLoop0
1.1.1.1/32
3/NULL
3.3.3.3
127.0.0.1
InLoop0
*1.1.1.1/32
Liberal/1024
DS/2.2.2.2
*1.1.1.1/32
Liberal/1024
DS/3.3.3.3
2.2.2.2/32
NULL/3
10.1.1.2
Vlanif10
2.2.2.2/32
1024/3
2.2.2.2
10.1.1.2
Vlanif10
2.2.2.2/32
1024/3
3.3.3.3
10.1.1.2
Vlanif10
*2.2.2.2/32
Liberal/1025
DS/3.3.3.3
3.3.3.3/32
NULL/1026
10.1.1.2
Vlanif10
3.3.3.3/32
1026/1026
2.2.2.2
10.1.1.2
Vlanif10
3.3.3.3/32
1026/1026
3.3.3.3
10.1.1.2
Vlanif10
*3.3.3.3/32
Liberal/3
DS/3.3.3.3
4.4.4.4/32
NULL/1025
10.1.1.2
Vlanif10
4.4.4.4/32
1025/1025
2.2.2.2
10.1.1.2
Vlanif10
4.4.4.4/32
1025/1025
3.3.3.3
10.1.1.2
Vlanif10
*4.4.4.4/32
Liberal/1026
DS/3.3.3.3
------------------------------------------------------------------------------TOTAL: 11 Normal LSP(s) Found.
TOTAL: 5 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
Step 5 Enable global BFD on the two nodes of the detected link.
# Configure PE1.
[PE1] bfd
[PE1-bfd] quit
# Configure PE2.
[PE2] bfd
[PE2-bfd] quit
Step 6 Bind the BFD session destined for the LDP LSP on PE1. Set the interval for sending
and receiving packets to both 100 ms. Configure the port status table to be
changeable.
# Configure PE1.
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[PE1] bfd pe1tope2 bind ldp-lsp peer-ip 4.4.4.4 nexthop 10.1.1.2 interface vlanif 10
[PE1-bfd-lsp-session-pe1tope2] discriminator local 1
[PE1-bfd-lsp-session-pe1tope2] discriminator remote 2
[PE1-bfd-lsp-session-pe1tope2] min-tx-interval 100
[PE1-bfd-lsp-session-pe1tope2] min-rx-interval 100
[PE1-bfd-lsp-session-pe1tope2] process-pst
[PE1-bfd-lsp-session-pe1tope2] commit
[PE1-bfd-lsp-session-pe1tope2] quit
Step 7 On PE2, configure a BFD session that is bound to the IP link to notify PE1 of the
detected faults on the LDP LSP.
# Configure PE2.
[PE2] bfd pe2tope1 bind peer-ip 1.1.1.1
[PE2-bfd-session-pe2tope1] discriminator local 2
[PE2-bfd-session-pe2tope1] discriminator remote 1
[PE2-bfd-session-pe2tope1] min-tx-interval 100
[PE2-bfd-session-pe2tope1] min-rx-interval 100
[PE2-bfd-session-pe2tope1] commit
[PE2-bfd-session-pe2tope1] quit
Step 8 Verify the configuration.
# Run the display bfd session all command on PE1. The command output shows
that the State field is displayed as Up.
[PE1] display bfd session all
-------------------------------------------------------------------------------Local Remote
PeerIpAddr
State
Type
InterfaceName
-------------------------------------------------------------------------------1
2
4.4.4.4
Up
S_LDP_LSP Vlanif10
-------------------------------------------------------------------------------Total UP/DOWN Session Number : 1/0
# Run the display bfd session all command on PE2, and the command output
that the State field is displayed as Up.
[PE2] display bfd session all
-------------------------------------------------------------------------------Local Remote
PeerIpAddr
State
Type
InterfaceName
-------------------------------------------------------------------------------2
1
1.1.1.1
Up
S_IP_PEER
-------------------------------------------------------------------------------Total UP/DOWN Session Number : 1/0
----End
Configuration Files
●
PE1 configuration file
#
sysname PE1
#
vlan batch 10 30
#
bfd
#
mpls lsr-id 1.1.1.1
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
mpls
mpls ldp
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4 MPLS LDP Configuration
#
interface Vlanif30
ip address 10.3.1.1 255.255.255.0
ospf cost 1000
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack1
ip address 1.1.1.1 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.1 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.3.1.0 0.0.0.255
#
bfd pe1tope2 bind ldp-lsp peer-ip 4.4.4.4 nexthop 10.1.1.2 interface Vlanif10
discriminator local 1
discriminator remote 2
min-tx-interval 100
min-rx-interval 100
process-pst
commit
#
return
●
P1 configuration file
#
sysname P1
#
vlan batch 10 20
#
mpls lsr-id 2.2.2.2
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack1
ip address 2.2.2.2 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.2 0.0.0.0
network 10.1.1.0 0.0.0.255
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network 10.2.1.0 0.0.0.255
#
return
●
P2 configuration file
#
sysname P2
#
vlan batch 30 40
#
mpls lsr-id 3.3.3.3
mpls
#
mpls ldp
#
interface Vlanif30
ip address 10.3.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif40
ip address 10.4.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 40
#
interface LoopBack1
ip address 3.3.3.3 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.3 0.0.0.0
network 10.3.1.0 0.0.0.255
network 10.4.1.0 0.0.0.255
#
return
●
PE2 configuration file
#
sysname PE2
#
vlan batch 20 40
#
bfd
#
mpls lsr-id 4.4.4.4
mpls
#
mpls ldp
#
interface Vlanif20
ip address 10.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif40
ip address 10.4.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
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4 MPLS LDP Configuration
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 40
#
interface LoopBack1
ip address 4.4.4.4 255.255.255.255
#
bfd pe2tope1 bind peer-ip 1.1.1.1
discriminator local 2
discriminator remote 1
min-tx-interval 100
min-rx-interval 100
commit
#
ospf 1
area 0.0.0.0
network 4.4.4.4 0.0.0.0
network 10.2.1.0 0.0.0.255
network 10.4.1.0 0.0.0.255
#
return
4.16.9 Example for Configuring Dynamic BFD to Detect LDP
LSPs
Networking Requirements
As shown in Figure 4-22, the network topology is complex and unstable. PEs and
P are MPLS backbone network devices, and LDP LSPs are set up on the backbone
network to transmit network services.
Network services, such as VoIP, online game, and online video service, have high
timeliness requirements. Data loss caused by faulty links will seriously affect
services. It is required that services be fast switched to the backup LSP when the
primary LSP becomes faulty, minimizing packet loss. Dynamic BFD for LDP LSPs is
configured to fast detect LDP LSPs.
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
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4 MPLS LDP Configuration
Figure 4-22 Networking diagram of dynamic BFD for LDP LSPs
Loopback1
2.2.2.2/32
G
1
10 E0/
/
0
.2
0/
0/ /24
VL .1.1/ 2
GE .1.2 10
24
AN
.1
F
G
IF2
Loopback1
/1 4 10 ANI
P1
10 E0/ Loopback1
0
/
L
0
2
0
.
2.1 0/1 4.4.4.4/32
V
1.1.1.1/32 GE .1/
V
1
0
.
.
L
AN 2/24
.1
F1
Primary LSP
10 ANI
IF2
0
VL
VL
0
AN
IF4
Backup LSP
N
PE1 10 GE0 IF30
LA 0/0/2 24 PE2
.3. /0/2
V
/
VL
1.1
GE .1.2
0
AN
4
/24
.4
IF
IF
G
10
AN /2
10 E0/ 30 P2
L
.3. 0/1
V
0/0 /24
1.2
GE .1.1
/24
.4
10
Loopback1
3.3.3.3/32
Configuration Roadmap
The configuration roadmap is as follows:
1.
Configure OSPF between the PEs and P to implement IP connectivity on the
backbone network.
2.
Configure local LDP sessions on PEs and P so that LDP LSPs can be set up to
transmit network services.
3.
Configure dynamic BFD on PEs to fast detect LDP LSPs.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
# Configure PE1. The configurations of P1, P2, and PE2 are similar to the
configuration of PE1, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname PE1
[PE1] interface loopback 1
[PE1-LoopBack1] ip address 1.1.1.1 32
[PE1-LoopBack1] quit
[PE1] interface gigabitethernet 0/0/1
[PE1-GigabitEthernet0/0/1] port link-type trunk
[PE1-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[PE1-GigabitEthernet0/0/1] quit
[PE1] interface gigabitethernet 0/0/2
[PE1-GigabitEthernet0/0/2] port link-type trunk
[PE1-GigabitEthernet0/0/2] port trunk allow-pass vlan 30
[PE1-GigabitEthernet0/0/2] quit
[PE1] vlan batch 10 30
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[PE1] interface vlanif 10
[PE1-Vlanif10] ip address 10.1.1.1 24
[PE1-Vlanif10] quit
[PE1] interface vlanif 30
[PE1-Vlanif30] ip address 10.3.1.1 24
[PE1-Vlanif30] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure PE1. The configurations of P1, P2, and PE2 are similar to the
configuration of PE1, and are not mentioned here.
[PE1] ospf 1
[PE1-ospf-1] area 0
[PE1-ospf-1-area-0.0.0.0]
[PE1-ospf-1-area-0.0.0.0]
[PE1-ospf-1-area-0.0.0.0]
[PE1-ospf-1-area-0.0.0.0]
[PE1-ospf-1] quit
network 1.1.1.1 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.3.1.0 0.0.0.255
quit
Step 3 Set the cost of VLANIF 30 on PE1 to 1000.
[PE1] interface vlanif 30
[PE1-Vlanif30] ospf cost 1000
[PE1-Vlanif30] quit
After the configuration is complete, run the display ip routing-table command
on each node. You can see that the nodes learn routes from each other. The
outbound interface of the route from PE1 to PE2 is VLANIF 10.
Step 4 Configure local LDP sessions.
# Configure PE1. The configurations of P1, P2, and PE2 are similar to the
configuration of PE1, and are not mentioned here.
[PE1] mpls lsr-id 1.1.1.1
[PE1] mpls
[PE1-mpls] quit
[PE1] mpls ldp
[PE1-mpls-ldp] quit
[PE1] interface vlanif 10
[PE1-Vlanif10] mpls
[PE1-Vlanif10] mpls ldp
[PE1-Vlanif10] quit
[PE1] interface vlanif 30
[PE1-Vlanif30] mpls
[PE1-Vlanif30] mpls ldp
[PE1-Vlanif30] quit
# Run the display mpls ldp lsp command. The command output shows that an
LDP LSP destined for 4.4.4.4/32 is set up on PE1.
[PE1] display mpls ldp lsp
LDP LSP Information
------------------------------------------------------------------------------Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------DestAddress/Mask In/OutLabel UpstreamPeer NextHop
OutInterface
------------------------------------------------------------------------------1.1.1.1/32
3/NULL
2.2.2.2
127.0.0.1
InLoop0
1.1.1.1/32
3/NULL
3.3.3.3
127.0.0.1
InLoop0
*1.1.1.1/32
Liberal/1024
DS/2.2.2.2
*1.1.1.1/32
Liberal/1024
DS/3.3.3.3
2.2.2.2/32
NULL/3
10.1.1.2
Vlanif10
2.2.2.2/32
1024/3
2.2.2.2
10.1.1.2
Vlanif10
2.2.2.2/32
1024/3
3.3.3.3
10.1.1.2
Vlanif10
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*2.2.2.2/32
Liberal/1025
DS/3.3.3.3
3.3.3.3/32
NULL/1026
10.1.1.2
Vlanif10
3.3.3.3/32
1026/1026
2.2.2.2
10.1.1.2
Vlanif10
3.3.3.3/32
1026/1026
3.3.3.3
10.1.1.2
Vlanif10
*3.3.3.3/32
Liberal/3
DS/3.3.3.3
4.4.4.4/32
NULL/1025
10.1.1.2
Vlanif10
4.4.4.4/32
1025/1025
2.2.2.2
10.1.1.2
Vlanif10
4.4.4.4/32
1025/1025
3.3.3.3
10.1.1.2
Vlanif10
*4.4.4.4/32
Liberal/1026
DS/3.3.3.3
------------------------------------------------------------------------------TOTAL: 11 Normal LSP(s) Found.
TOTAL: 5 Liberal LSP(s) Found.
TOTAL: 0 Frr LSP(s) Found.
A '*' before an LSP means the LSP is not established
A '*' before a Label means the USCB or DSCB is stale
A '*' before a UpstreamPeer means the session is stale
A '*' before a DS means the session is stale
A '*' before a NextHop means the LSP is FRR LSP
Step 5 Configure dynamic BFD to detect the connectivity of the LDP LSP between PE1
and PE2.
# Configure an FEC list on PE1 to ensure that BFD detects only the connectivity of
the LDP LSP between PE1 and PE2.
[PE1] fec-list tortc
[PE1-fec-list-tortc] fec-node 4.4.4.4
[PE1-fec-list-tortc] quit
# Enable BFD on PE1, specify the FEC list that triggers BFD session establishment
dynamically, and adjust BFD parameters.
[PE1] bfd
[PE1-bfd] quit
[PE1] mpls
[PE1-mpls] mpls bfd-trigger fec-list tortc
[PE1-mpls] mpls bfd enable
[PE1-mpls] mpls bfd min-tx-interval 100 min-rx-interval 100
[PE1-mpls] quit
# Enable BFD for LSPs passively on PE2.
[PE2] bfd
[PE2-bfd] mpls-passive
[PE2-bfd] quit
Step 6 Verify the configuration.
# Run the display bfd session all command to view the BFD session status that is
created dynamically. The command output shows that the State field is displayed
as Up.
[PE1] display bfd session all
-------------------------------------------------------------------------------Local Remote
PeerIpAddr
State
Type
InterfaceName
-------------------------------------------------------------------------------8192 8192
4.4.4.4
Up
D_LDP_LSP Vlanif10
-------------------------------------------------------------------------------Total UP/DOWN Session Number : 1/0
# Check the status of the BFD session created dynamically on PE2. The command
output shows that the State field is displayed as Up.
[PE2] display bfd session passive-dynamic
-------------------------------------------------------------------------------Local Remote
PeerIpAddr
State
Type
InterfaceName
-------------------------------------------------------------------------------8192 8192
1.1.1.1
Up
E_Dynamic
-
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-------------------------------------------------------------------------------Total UP/DOWN Session Number : 1/0
----End
Configuration Files
●
PE1 configuration file
#
sysname PE1
#
vlan batch 10 30
#
bfd
#
mpls lsr-id 1.1.1.1
mpls
mpls bfd enable
mpls bfd-trigger fec-list tortc
mpls bfd min-tx-interval 100 min-rx-interval 100
#
fec-list tortc
fec-node 4.4.4.4
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
mpls
mpls ldp
#
interface Vlanif30
ip address 10.3.1.1 255.255.255.0
ospf cost 1000
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack1
ip address 1.1.1.1 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.1 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.3.1.0 0.0.0.255
#
return
●
P1 configuration file
#
sysname P1
#
vlan batch 10 20
#
mpls lsr-id 2.2.2.2
mpls
#
mpls ldp
#
interface Vlanif10
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ip address 10.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack1
ip address 2.2.2.2 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.2 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
#
return
●
P2 configuration file
#
sysname P2
#
vlan batch 30 40
#
mpls lsr-id 3.3.3.3
mpls
#
mpls ldp
#
interface Vlanif30
ip address 10.3.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif40
ip address 10.4.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 40
#
interface LoopBack1
ip address 3.3.3.3 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.3 0.0.0.0
network 10.3.1.0 0.0.0.255
network 10.4.1.0 0.0.0.255
#
return
●
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PE2 configuration file
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#
sysname PE2
#
vlan batch 20 40
#
bfd
mpls-passive
#
mpls lsr-id 4.4.4.4
mpls
#
mpls ldp
#
interface Vlanif20
ip address 10.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif40
ip address 10.4.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 40
#
interface LoopBack1
ip address 4.4.4.4 255.255.255.255
#
ospf 1
area 0.0.0.0
network 4.4.4.4 0.0.0.0
network 10.2.1.0 0.0.0.255
network 10.4.1.0 0.0.0.255
#
return
4.16.10 Example for Configuring Synchronization Between
LDP and IGP
Networking Requirements
As shown in Figure 4-23, P1, P2, P3, and PE2 exist on the MPLS backbone network
and OSPF runs between devices. Two LSPs are set up between PE1 and PE2 to
transmit services: primary LSP (PE1 -> P1 -> P2 -> PE2) and backup LSP (PE1 -> P1
-> P3 -> PE2). After the primary link recovers, the IGP route of the primary link
becomes active before an LDP session is established over the primary link. As a
result, traffic is dropped during attempts to use the unreachable LSP. Short-time
interruption of delay-sensitive services such as VoIP, online game, and online video
service is unacceptable. It is required that the MPLS traffic loss be solved in this
networking.
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
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Figure 4-23 Networking diagram for configuring synchronization between LDP
and IGP
PE1
Lookback1
2.2.2.9/32 G
/1 4
10 E0/
0
/
.2 0/
0 2/2
E
V
LA .1.1/ 2
G .1. 10
NI 24 G
0.1 IF
F2 1 E
/1 4 1 LAN
0 0. 0/0
0
/
V
2
0
P2
/
VL 2.1. /1
GE .1.1 10
AN 2/2
.1 NIF
IF2 4
0
1 LA
0 PE2
V
Lookback1
Lookback1
4.4.4.9/32
1.1.1.9/32
G
2
P11 E
0/
0/
Lookback1
0
0/ 2/24
E
.
VL .3.1. 0/2
G .1 F40
3.3.3.9/32
AN 1/2
.4 I
GE
IF 4
10 LAN
2
30 10
/
0
V
/
0/0 /24
VL .3.1. 0/1
GE .1.1 40
AN 2/2
.4 IF
IF3 4
primary link
10 LAN
0
P3
V
backup link
Configuration Roadmap
To meet the preceding requirements, configure synchronization between LDP and
IGP. The configuration roadmap is as follows:
1.
Configure OSPF on Ps and PE2 to implement IP connectivity on the backbone
network.
2.
Configure local LDP sessions on Ps and PE2 so that LDP LSPs can be set up to
transmit network services.
3.
Configure synchronization between LDP and IGP on P1 and P2 to prevent
traffic loss.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
# Configure P1. The configurations of P2, P3, and PE2 are similar to the
configuration of P1, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname P1
[P1] interface loopback 1
[P1-LoopBack1] ip address 1.1.1.9 32
[P1-LoopBack1] quit
[P1] vlan batch 10 30
[P1] interface vlanif 10
[P1-Vlanif10] ip address 10.1.1.1 24
[P1-Vlanif10] quit
[P1] interface vlanif 30
[P1-Vlanif30] ip address 10.3.1.1 24
[P1-Vlanif30] quit
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[P1] interface gigabitethernet 0/0/1
[P1-GigabitEthernet0/0/1] port link-type trunk
[P1-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[P1-GigabitEthernet0/0/1] quit
[P1] interface gigabitethernet 0/0/2
[P1-GigabitEthernet0/0/2] port link-type trunk
[P1-GigabitEthernet0/0/2] port trunk allow-pass vlan 30
[P1-GigabitEthernet0/0/2] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure P1. The configurations of P2, P3, and PE2 are similar to the
configuration of P1, and are not mentioned here.
[P1] ospf 1
[P1-ospf-1] area 0
[P1-ospf-1-area-0.0.0.0]
[P1-ospf-1-area-0.0.0.0]
[P1-ospf-1-area-0.0.0.0]
[P1-ospf-1-area-0.0.0.0]
[P1-ospf-1] quit
network 1.1.1.9 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.3.1.0 0.0.0.255
quit
Step 3 Set the cost of VLANIF 30 on P1 to 1000.
[P1] interface vlanif 30
[P1-Vlanif30] ospf cost 1000
[P1-Vlanif30] quit
After the configuration is complete, run the display ip routing-table command
on each node. The command output shows that the nodes have learned routes
from each other. The outbound interface of P1-to-PE2 route is VLANIF 10.
Step 4 Enable MPLS and MPLS LDP on each node and each interface.
# Configure P1.
[P1] mpls lsr-id 1.1.1.9
[P1] mpls
[P1-mpls] quit
[P1] mpls ldp
[P1-mpls-ldp] quit
[P1] interface vlanif 10
[P1-Vlanif10] mpls
[P1-Vlanif10] mpls ldp
[P1-Vlanif10] quit
[P1] interface vlanif 30
[P1-Vlanif30] mpls
[P1-Vlanif30] mpls ldp
[P1-Vlanif30] quit
# Configure P2.
[P2] mpls lsr-id 2.2.2.9
[P2] mpls
[P2-mpls] quit
[P2] mpls ldp
[P2-mpls-ldp] quit
[P2] interface vlanif 10
[P2-Vlanif10] mpls
[P2-Vlanif10] mpls ldp
[P2-Vlanif10] quit
[P2] interface vlanif 20
[P2-Vlanif20] mpls
[P2-Vlanif20] mpls ldp
[P2-Vlanif20] quit
# Configure P3.
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[P3] mpls lsr-id 3.3.3.9
[P3] mpls
[P3-mpls] quit
[P3] mpls ldp
[P3-mpls-ldp] quit
[P3] interface vlanif 30
[P3-Vlanif30] mpls
[P3-Vlanif30] mpls ldp
[P3-Vlanif30] quit
[P3] interface vlanif 40
[P3-Vlanif40] mpls
[P3-Vlanif40] mpls ldp
[P3-Vlanif40] quit
# Configure PE2.
[PE2] mpls lsr-id 4.4.4.9
[PE2] mpls
[PE2-mpls] quit
[PE2] mpls ldp
[PE2-mpls-ldp] quit
[PE2] interface vlanif 20
[PE2-Vlanif20] mpls
[PE2-Vlanif20] mpls ldp
[PE2-Vlanif20] quit
[PE2] interface vlanif 40
[PE2-Vlanif40] mpls
[PE2-Vlanif40] mpls ldp
[PE2-Vlanif40] quit
After the configuration is complete, LDP sessions are established between
neighboring nodes. Run the display mpls ldp session command on each node.
The command output shows that the LDP session status is Operational. Use the
display on P1 as an example.
[P1] display mpls ldp session
LDP Session(s) in Public Network
Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDDD:HH:MM)
A '*' before a session means the session is being deleted.
-----------------------------------------------------------------------------PeerID
Status
LAM SsnRole SsnAge
KASent/Rcv
-----------------------------------------------------------------------------2.2.2.9:0
Operational DU Active 000:00:56 227/227
3.3.3.9:0
Operational DU Active 000:00:56 227/227
-----------------------------------------------------------------------------TOTAL: 2 session(s) Found.
Step 5 Enable synchronization between LDP and IGP on the interfaces at both ends of the
link between P1 and P2.
# Configure P1.
[P1] interface vlanif 10
[P1-Vlanif10] ospf ldp-sync
[P1-Vlanif10] quit
# Configure P2.
[P2] interface vlanif 10
[P2-Vlanif10] ospf ldp-sync
[P2-Vlanif10] quit
Step 6 Set the value of Hold-down timer on the interfaces at both ends of the link
between P1 and P2.
# Configure P1.
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[P1] interface vlanif 10
[P1-Vlanif10] ospf timer ldp-sync hold-down 8
[P1-Vlanif10] quit
# Configure P2.
[P2] interface vlanif 10
[P2-Vlanif10] ospf timer ldp-sync hold-down 8
[P2-Vlanif10] quit
Step 7 Set the value of Hold-max-cost timer on the interfaces at both ends of the link
between P1 and P2.
# Configure P1.
[P1] interface vlanif 10
[P1-Vlanif10] ospf timer ldp-sync hold-max-cost 9
[P1-Vlanif10] quit
# Configure P2.
[P2] interface vlanif 10
[P2-Vlanif10] ospf timer ldp-sync hold-max-cost 9
[P2-Vlanif10] quit
Step 8 Verify the configuration.
Run the display ospf ldp-sync command on P1. The command output shows that
the interface status is Sync-Achieved.
[P1] display ospf ldp-sync interface vlanif 10
Interface Vlanif10
HoldDown Timer: 8
HoldMaxCost Timer: 9
LDP State: Up
OSPF Sync State: Sync-Achieved
----End
Configuration Files
●
P1 configuration file
#
sysname P1
#
vlan batch 10 30
#
mpls lsr-id 1.1.1.9
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
ospf ldp-sync
ospf timer ldp-sync hold-down 8
ospf timer ldp-sync hold-max-cost 9
mpls
mpls ldp
#
interface Vlanif30
ip address 10.3.1.1 255.255.255.0
ospf cost 1000
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
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interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.3.1.0 0.0.0.255
#
return
●
P2 configuration file
#
sysname P2
#
vlan batch 10 20
#
mpls lsr-id 2.2.2.9
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
ospf ldp-sync
ospf timer ldp-sync hold-down 8
ospf timer ldp-sync hold-max-cost 9
mpls
mpls ldp
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
#
return
●
P3 configuration file
#
sysname P3
#
vlan batch 30 40
#
mpls lsr-id 3.3.3.9
mpls
#
mpls ldp
#
interface Vlanif30
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ip address 10.3.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif40
ip address 10.4.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 40
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 10.3.1.0 0.0.0.255
network 10.4.1.0 0.0.0.255
#
return
●
PE2 configuration file
#
sysname PE2
#
vlan batch 20 40
#
mpls lsr-id 4.4.4.9
mpls
#
mpls ldp
#
interface Vlanif20
ip address 10.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif40
ip address 10.4.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 40
#
interface LoopBack1
ip address 4.4.4.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 4.4.4.9 0.0.0.0
network 10.2.1.0 0.0.0.255
network 10.4.1.0 0.0.0.255
#
return
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4 MPLS LDP Configuration
4.16.11 Example for Configuring LDP GR
Networking Requirements
As shown in Figure 4-24, LSRA, LSRB, and LSRC are devices on the MPLS
backbone network. Each of the three devices is a member in a stack, and it is
required that services are not interrupted when an active/standby switchover
occurs on LSRA, LSRB, and LSRC.
Figure 4-24 Networking diagram for configuring LDP GR
Loopback0
Loopback0
Loopback0
1.1.1.1/32
2.2.2.2/32
3.3.3.3/32
GE0/0/1
GE0/0/1
GE0/0/1
GE0/0/2
10.1.1.1/24 10.1.1.2/24
10.2.1.1/24 10.2.1.2/24
VLANIF10
LSRA
VLANIF10
VLANIF20 VLANIF20
LSRB
LSRC
Configuration Roadmap
To meet the preceding requirements, configure LDP GR. The configuration
roadmap is as follows:
1.
Configure OSPF on LSRs to implement IP connectivity on the backbone
network.
2.
Configure local LDP sessions on LSRs so that LDP LSPs can be set up to
transmit network services.
3.
Configure LDP GR on LSRs to prevent short-time traffic interruption.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
# Configure LSRA. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 0
[LSRA-LoopBack0] ip address 1.1.1.1 32
[LSRA-LoopBack0] quit
[LSRA] vlan batch 10
[LSRA] interface vlanif 10
[LSRA-Vlanif10] ip address 10.1.1.1 24
[LSRA-Vlanif10] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
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# Configure LSRA.
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.1 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
# Configure LSRB.
[LSRB] ospf 1
[LSRB-ospf-1] area 0
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1-area-0.0.0.0]
[LSRB-ospf-1] quit
network 2.2.2.2 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
quit
# Configure LSRC.
[LSRC] ospf 1
[LSRC-ospf-1] area 0
[LSRC-ospf-1-area-0.0.0.0] network 3.3.3.3 0.0.0.0
[LSRC-ospf-1-area-0.0.0.0] network 10.2.1.0 0.0.0.255
[LSRC-ospf-1-area-0.0.0.0] quit
[LSRC-ospf-1] quit
After the configuration is complete, run the display ip routing-table command
on each node, and you can view that the nodes learn routes from each other.
Step 3 Configure OSPF GR.
# Configure LSRA.
[LSRA] ospf 1
[LSRA-ospf-1] opaque-capability enable
[LSRA-ospf-1] graceful-restart
[LSRA-ospf-1] quit
# Configure LSRB.
[LSRB] ospf 1
[LSRB-ospf-1] opaque-capability enable
[LSRB-ospf-1] graceful-restart
[LSRB-ospf-1] quit
# Configure LSRC.
[LSRC] ospf 1
[LSRC-ospf-1] opaque-capability enable
[LSRC-ospf-1] graceful-restart
[LSRC-ospf-1] quit
Step 4 Configure local LDP sessions.
# Configure LSRA. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] mpls lsr-id 1.1.1.1
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
[LSRA] interface vlanif 10
[LSRA-Vlanif10] mpls
[LSRA-Vlanif10] mpls ldp
[LSRA-Vlanif10] quit
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4 MPLS LDP Configuration
After the configuration is complete, local LDP sessions are established between
LSRA and LSRB, and between LSRB and LSRC.
Run the display mpls ldp session command on each node to view the
establishment of the LDP session. LSRA is used as an example.
[LSRA] display mpls ldp session
LDP Session(s) in Public Network
Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDDD:HH:MM)
A '*' before a session means the session is being deleted.
-----------------------------------------------------------------------------PeerID
Status
LAM SsnRole SsnAge
KASent/Rcv
-----------------------------------------------------------------------------2.2.2.2:0
Operational DU Passive 0000:00:02 9/9
-----------------------------------------------------------------------------TOTAL: 1 session(s) Found.
Step 5 Configure LDP GR.
# Configure LSRA.
[LSRA] mpls ldp
[LSRA-mpls-ldp] graceful-restart
[LSRA-mpls-ldp] quit
# Configure LSRB.
[LSRB] mpls ldp
[LSRB-mpls-ldp] graceful-restart
[LSRB-mpls-ldp] quit
# Configure LSRC.
[LSRC] mpls ldp
[LSRC-mpls-ldp] graceful-restart
[LSRC-mpls-ldp] quit
Step 6 Verify the configuration.
# Run the display mpls ldp session verbose command on the LSRs. The
command output shows that the Session FT Flag field is displayed as On. LSRA is
used as an example.
[LSRA] display mpls ldp session verbose
LDP Session(s) in Public Network
-----------------------------------------------------------------------------Peer LDP ID
: 2.2.2.2:0
Local LDP ID : 1.1.1.1:0
TCP Connection : 1.1.1.1 <- 2.2.2.2
Session State : Operational
Session Role : Passive
Session FT Flag : On
MD5 Flag
: Off
Reconnect Timer : 300 Sec
Recovery Timer : 300 Sec
Keychain Name : --Authentication applied : --Negotiated Keepalive Hold Timer : 45 Sec
Configured Keepalive Send Timer : --Keepalive Message Sent/Rcvd
: 4/4 (Message Count)
Label Advertisement Mode
: Downstream Unsolicited
Label Resource Status(Peer/Local) : Available/Available
Session Age
: 0000:00:00 (DDDD:HH:MM)
Session Deletion Status
: No
Capability:
Capability-Announcement
mLDP P2MP Capability
mLDP MP2MP Capability
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: Off
: Off
: Off
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mLDP MBB Capability
4 MPLS LDP Configuration
: Off
Outbound&Inbound Policies applied : NULL
Addresses received from peer: (Count: 3)
2.2.2.2
10.1.1.2
10.2.1.1
------------------------------------------------------------------------------
# Or run the display mpls ldp peer verbose command on the LSRs. The
command output shows that the Peer FT Flag field is displayed as On. LSRA is
used as an example.
[LSRA] display mpls ldp peer verbose
LDP Peer Information in Public network
-----------------------------------------------------------------------------Peer LDP ID
: 2.2.2.2:0
Peer Max PDU Length : 4096
Peer Transport Address : 2.2.2.2
Peer Path Vector Limit : ---Peer Loop Detection : Off
Peer FT Flag
: On
Peer Keepalive Timer : 45 Sec
Recovery Timer
: 300 Sec
Reconnect Timer
: 300 Sec
Peer Type
: Local
Peer Label Advertisement Mode : Downstream Unsolicited
Peer Discovery Source
: Vlanif10
Peer Deletion Status
: No
Capability-Announcement
: Off
Peer mLDP P2MP Capability
: Off
Peer mLDP MP2MP Capability : Off
Peer mLDP MBB Capability
: Off
------------------------------------------------------------------------------
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 10
#
mpls lsr-id 1.1.1.1
mpls
#
mpls ldp
graceful-restart
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
#
ospf 1
opaque-capability enable
graceful-restart
area 0.0.0.0
network 1.1.1.1 0.0.0.0
network 10.1.1.0 0.0.0.255
#
return
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●
4 MPLS LDP Configuration
LSRB configuration file
#
sysname LSRB
#
vlan batch 10 20
#
mpls lsr-id 2.2.2.2
mpls
#
mpls ldp
graceful-restart
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 2.2.2.2 255.255.255.255
#
ospf 1
opaque-capability enable
graceful-restart
area 0.0.0.0
network 2.2.2.2 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 20
#
mpls lsr-id 3.3.3.3
mpls
#
mpls ldp
graceful-restart
#
interface Vlanif20
ip address 10.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 3.3.3.3 255.255.255.255
#
ospf 1
opaque-capability enable
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4 MPLS LDP Configuration
graceful-restart
area 0.0.0.0
network 3.3.3.3 0.0.0.0
network 10.2.1.0 0.0.0.255
#
return
4.16.12 Example for Configuring Manual LDP FRR
Networking Requirements
As shown in Figure 4-25, the network topology is simple and stable, and LSRA,
LSRB, and LSRC are MPLS backbone network devices. Two LSPs are set up
between LSRA and LSRC to transmit services: primary LSP (LSRA -> LSRC) and
backup LSP (LSRA -> LSRB -> PEC). When the primary LSP becomes faulty, traffic
is switched to the backup LSP, causing MPLS traffic loss. Short-time interruption of
delay-sensitive services such as VoIP, online game, and online video service is
unacceptable. It is required that services be fast switched to the backup LSP when
the primary LSP becomes faulty, minimizing packet loss.
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
Figure 4-25 Networking diagram for configuring manual LDP FRR
Loopback1
2.2.2.9/32
LSRA 1 GE0
0
/
VL .3.1. 0/2
AN 1/3
IF2 0
G
0
10 E0/0
.
VL 3.1.2 /1
AN /3
IF2 0
Primary LSP
0
Backup LSP
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LSRB
GE0/0/2
GE0/0/2
10.2.1.1/30 10.2.1.2/30
VLANIF30 VLANIF30
/1
0/0 2/30
E
G .1. 10
.1 IF
1
10 AN
/
0
Loopback1 E0/ /30 VL
.1
1.1.1.9/32 G .1.1 IF10
0
1 AN
VL
LSRC
Loopback1
3.3.3.9/32
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4 MPLS LDP Configuration
Configuration Roadmap
To meet the preceding requirements, configure manual LDP FRR. The
configuration roadmap is as follows:
1.
Configure OSPF on LSRs to implement IP connectivity on the backbone
network.
2.
Configure local LDP sessions on LSRs so that LDP LSPs can be set up to
transmit network services.
3.
Configure static BFD for LDP LSPs on LSRA and LSRC to fast detect faults on
LDP LSPs.
4.
Configure manual LDP FRR on LSRA to minimize packet loss during the
active/standby switchover.
On a network where manual LDP FRR is enabled, the backup LSP must be in liberal state.
When you run the display ip routing-table ip-address verbose command on an LSR that is
enabled with FRR, the command output shows that the status of the backup LSP route is
Inactive Adv.
Procedure
Step 1 On the switches, create VLANs and VLANIF interfaces, configure IP addresses for
the VLANIF interfaces, and add physical interfaces to VLANs.
# Configure LSRA. The configurations of LSRB and LSRC are similar to that of
LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 1
[LSRA-LoopBack1] ip address 1.1.1.9 32
[LSRA-LoopBack1] quit
[LSRA] vlan batch 10 20
[LSRA] interface vlanif 10
[LSRA-Vlanif10] ip address 10.1.1.1 30
[LSRA-Vlanif10] quit
[LSRA] interface vlanif 20
[LSRA-Vlanif20] ip address 10.3.1.1 30
[LSRA-Vlanif20] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface gigabitethernet 0/0/2
[LSRA-GigabitEthernet0/0/2] port link-type trunk
[LSRA-GigabitEthernet0/0/2] port trunk allow-pass vlan 20
[LSRA-GigabitEthernet0/0/2] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure LSRA. The configurations of LSRB and LSRC are similar to that of
LSRA, and are not mentioned here.
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.3
[LSRA-ospf-1-area-0.0.0.0] network 10.3.1.0 0.0.0.3
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4 MPLS LDP Configuration
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
After the configuration is complete, run the display ip routing-table command
on each node. The command output shows that the nodes have learned routes
from each other.
Step 3 Enable MPLS and MPLS LDP on each node globally and on the interfaces.
# Configure LSRA. The configurations of LSRB and LSRC are similar to that of
LSRA, and are not mentioned here.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
[LSRA] interface vlanif 10
[LSRA-Vlanif10] mpls
[LSRA-Vlanif10] mpls ldp
[LSRA-Vlanif10] quit
[LSRA] interface vlanif 20
[LSRA-Vlanif20] mpls
[LSRA-Vlanif20] mpls ldp
[LSRA-Vlanif20] quit
After the configuration is complete, LDP sessions are established between
neighboring nodes. Run the display mpls ldp session command on each node.
The command output shows that the LDP session status is Operational. LSRA is
used as an example.
[LSRA] display mpls ldp session
LDP Session(s) in Public Network
Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDDD:HH:MM)
A '*' before a session means the session is being deleted.
-----------------------------------------------------------------------------PeerID
Status
LAM SsnRole SsnAge
KASent/Rcv
-----------------------------------------------------------------------------2.2.2.9:0
Operational DU Passive 0000:00:01 8/8
3.3.3.9:0
Operational DU Passive 0000:00:01 6/6
-----------------------------------------------------------------------------TOTAL: 2 session(s) Found.
Step 4 Configure static BFD for LDP LSPs on LSRA and LSRC.
# Configure LSRA.
[LSRA] bfd
[LSRA-bfd] quit
[LSRA] bfd lsratoc bind ldp-lsp peer-ip 3.3.3.9 nexthop 10.3.1.2 interface vlanif 20
[LSRA-bfd-lsp-session-lsratoc] discriminator local 1
[LSRA-bfd-lsp-session-lsratoc] discriminator remote 2
[LSRA-bfd-lsp-session-lsratoc] min-tx-interval 100
[LSRA-bfd-lsp-session-lsratoc] min-rx-interval 100
[LSRA-bfd-lsp-session-lsratoc] process-pst
[LSRA-bfd-lsp-session-lsratoc] commit
[LSRA-bfd-lsp-session-lsratoc] quit
# Configure LSRC.
[LSRC] bfd
[LSRC-bfd] quit
[LSRC] bfd lsrctoa bind peer-ip 1.1.1.9
[LSRC-bfd-session-lsrctoa] discriminator local 2
[LSRC-bfd-session-lsrctoa] discriminator remote 1
[LSRC-bfd-session-lsrctoa] min-tx-interval 100
[LSRC-bfd-session-lsrctoa] min-rx-interval 100
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4 MPLS LDP Configuration
[LSRC-bfd-session-lsrctoa] commit
[LSRC-bfd-session-lsrctoa] quit
After the configuration is complete, run the display bfd session all command on
LSRA. You can see that the value of the State field is Up.
Step 5 Enable manual LDP FRR on VLANIF 20 of LSRA, and specify the next hop address
used to create the backup LSP.
# Configure LSRA.
[LSRA] interface vlanif 20
[LSRA-Vlanif20] mpls ldp frr nexthop 10.1.1.2
[LSRA-Vlanif20] quit
Step 6 Verify the configuration.
Run the display mpls lsp command on LSRA. The command output shows that
manual LDP FRR is enabled on the LSP of LSRC.
[LSRA] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
1.1.1.9/32
3/NULL
-/2.2.2.9/32
NULL/3
-/Vlanif10
2.2.2.9/32
1024/3
-/Vlanif10
3.3.3.9/32
NULL/3
-/Vlanif20
**LDP FRR**
/1025
/Vlanif10
3.3.3.9/32
1025/3
-/Vlanif20
**LDP FRR**
/1025
/Vlanif10
Connect two interfaces, Port 1 and Port 2, on a tester to LSRA and LSRC
respectively. On Port 1, inject MPLS traffic and send traffic to Port 2. Run the
shutdown command on VLANIF 20 of LSRA to simulate a fault on the primary
LSP. You can see that traffic is fast switched to the backup LSP.
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 10 20
#
bfd
#
mpls lsr-id 1.1.1.9
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.252
mpls
mpls ldp
#
interface Vlanif20
ip address 10.3.1.1 255.255.255.252
mpls
mpls ldp
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4 MPLS LDP Configuration
mpls ldp frr nexthop 10.1.1.2
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 10.1.1.0 0.0.0.3
network 10.3.1.0 0.0.0.3
#
bfd lsratoc bind ldp-lsp peer-ip 3.3.3.9 nexthop 10.3.1.2 interface Vlanif20
discriminator local 1
discriminator remote 2
min-tx-interval 100
min-rx-interval 100
process-pst
commit
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 10 30
#
mpls lsr-id 2.2.2.9
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.252
mpls
mpls ldp
#
interface Vlanif30
ip address 10.2.1.1 255.255.255.252
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 10.1.1.0 0.0.0.3
network 10.2.1.0 0.0.0.3
#
return
●
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LSRC configuration file
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4 MPLS LDP Configuration
#
sysname LSRC
#
vlan batch 20 30
#
bfd
#
mpls lsr-id 3.3.3.9
mpls
#
mpls ldp
#
interface Vlanif20
ip address 10.3.1.2 255.255.255.252
mpls
mpls ldp
#
interface Vlanif30
ip address 10.2.1.2 255.255.255.252
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
bfd lsrctoa bind peer-ip 1.1.1.9
discriminator local 2
discriminator remote 1
min-tx-interval 100
min-rx-interval 100
commit
#
ospf 1
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 10.2.1.0 0.0.0.3
network 10.3.1.0 0.0.0.3
#
return
4.16.13 Example for Configuring Auto LDP FRR
Networking Requirements
As shown in Figure 4-26, the network topology is complex and unstable, and
LSRA, LSRB, LSRC, and LSRD are MPLS backbone network devices. Two LSPs are
set up between LSRA and LSRC to transmit services: primary LSP (LSRA -> LSRC)
and backup LSP (LSRA -> LSRB -> LSRC). When the primary LSP becomes faulty,
traffic is switched to the backup LSP, causing MPLS traffic loss. Short-time
interruption of delay-sensitive services such as VoIP, online game, and online video
service is unacceptable. It is required that services be fast switched to the backup
LSP when the primary LSP becomes faulty, minimizing packet loss.
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4 MPLS LDP Configuration
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
Figure 4-26 Networking diagram of configuring Auto LDP FRR
10 GE
VL .1. 0/0
AN 1.1 /1
IF /24
10
Backup LSP
GE0/0/3
LSRD
10.1.4.1/24
LSRC
VLANIF30
GE0/0/1
GE0/0/1
10.1.2.2/24
10.1.4.2/24
VLANIF20 Loopback0 VLANIF30 Loopback0
3.3.3.9/32
4.4.4.9/32
Primary LSP
GE0/0/2
10.1.2.1/24
Loopback0 VLANIF20
1.1.1.9/32
/2
/0 /24
E0 .2 0
G 1.3 IF4
. N
10 LA
V
LSRA
LSRB
/2
/0 /24
E0 .1 0
G 1.3 IF4
. N
10 LA
V
10 GE
VL .1. 0/0
AN 1.2 /1
IF /24
10
Loopback0
2.2.2.9/32
Configuration Roadmap
To meet the preceding requirements, configure Auto LDP FRR. The configuration
roadmap is as follows:
1.
Configure IS-IS on LSRs to implement IP connectivity on the backbone
network.
2.
Configure local LDP sessions on LSRs so that LDP LSPs can be set up to
transmit network services.
3.
Configure dynamic BFD for LDP LSPs on LSRA and LSRC to fast detect faults
on LDP LSPs.
4.
Configure Auto LDP FRR on LSRA to minimize packet loss during the active/
standby switchover.
Procedure
Step 1 On the switches, create VLANs and VLANIF interfaces, configure IP addresses for
the VLANIF interfaces, and add physical interfaces to VLANs.
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 0
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4 MPLS LDP Configuration
[LSRA-LoopBack0] ip address 1.1.1.9 32
[LSRA-LoopBack0] quit
[LSRA] vlan batch 10 20
[LSRA] interface vlanif 10
[LSRA-Vlanif10] ip address 10.1.1.1 24
[LSRA-Vlanif10] quit
[LSRA] interface vlanif 20
[LSRA-Vlanif20] ip address 10.1.2.1 24
[LSRA-Vlanif20] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface gigabitethernet 0/0/2
[LSRA-GigabitEthernet0/0/2] port link-type trunk
[LSRA-GigabitEthernet0/0/2] port trunk allow-pass vlan 20
[LSRA-GigabitEthernet0/0/2] quit
Step 2 Configure IS-IS to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure LSRA.
[LSRA] isis 1
[LSRA-isis-1] network-entity 10.0000.0000.0001.00
[LSRA-isis-1] quit
[LSRA] interface vlanif 10
[LSRA-Vlanif10] isis enable 1
[LSRA-Vlanif10] quit
[LSRA] interface vlanif 20
[LSRA-Vlanif20] isis enable 1
[LSRA-Vlanif20] quit
[LSRA] interface loopback 0
[LSRA-LoopBack0] isis enable 1
[LSRA-LoopBack0] quit
# Configure LSRB.
[LSRB] isis 1
[LSRB-isis-1] network-entity 10.0000.0000.0002.00
[LSRB-isis-1] quit
[LSRB] interface vlanif 10
[LSRB-Vlanif10] isis enable 1
[LSRB-Vlanif10] quit
[LSRB] interface vlanif 40
[LSRB-Vlanif40] isis enable 1
[LSRB-Vlanif40] quit
[LSRB] interface loopback 0
[LSRB-LoopBack0] isis enable 1
[LSRB-LoopBack0] quit
# Configure LSRC.
[LSRC] isis 1
[LSRC-isis-1] network-entity 10.0000.0000.0003.00
[LSRC-isis-1] quit
[LSRC] interface vlanif 30
[LSRC-Vlanif30] isis enable 1
[LSRC-Vlanif30] quit
[LSRC] interface vlanif 20
[LSRC-Vlanif20] isis enable 1
[LSRC-Vlanif20] quit
[LSRC] interface vlanif 40
[LSRC-Vlanif40] isis enable 1
[LSRC-Vlanif40] quit
[LSRC] interface loopback 0
[LSRC-LoopBack0] isis enable 1
[LSRC-LoopBack0] quit
# Configure LSRD.
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4 MPLS LDP Configuration
[LSRD] isis 1
[LSRD-isis-1] network-entity 10.0000.0000.0004.00
[LSRD-isis-1] quit
[LSRD] interface vlanif 30
[LSRD-Vlanif30] isis enable 1
[LSRD-Vlanif30] quit
[LSRD] interface loopback 0
[LSRD-LoopBack0] isis enable 1
[LSRD-LoopBack0] quit
Step 3 Configure global and interface-based MPLS and MPLS LDP on each node so that
the network can forward MPLS traffic. Then check the LSP setup result.
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
[LSRA] interface vlanif 10
[LSRA-Vlanif10] mpls
[LSRA-Vlanif10] mpls ldp
[LSRA-Vlanif10] quit
[LSRA] interface vlanif 20
[LSRA-Vlanif20] mpls
[LSRA-Vlanif20] mpls ldp
[LSRA-Vlanif20] quit
# After the configuration is complete, run the display mpls lsp command on LSRA
to view the established LSP.
[LSRA] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
1.1.1.9/32
3/NULL
-/2.2.2.9/32
NULL/3
-/Vlanif10
2.2.2.9/32
1024/3
-/Vlanif10
3.3.3.9/32
NULL/3
-/Vlanif20
3.3.3.9/32
1025/3
-/Vlanif20
4.4.4.9/32
NULL/1026
-/Vlanif20
4.4.4.9/32
1026/1026
-/Vlanif20
The preceding command output shows that by default, the routes with 32-bit
addresses trigger the setup of LSPs.
Step 4 Configure dynamic BFD to detect connectivity of the LDP LSP between LSRA and
LSRC.
# Configure an FEC list on LSRA to ensure that BFD detects only connectivity of
the LDP LSP between LSRA and LSRC.
[LSRA] fec-list tortc
[LSRA-fec-list-tortc] fec-node 3.3.3.9
[LSRA-fec-list-tortc] quit
# Enable BFD on LSRA, specify the FEC list that triggers a BFD session dynamically,
and adjust BFD parameters.
[LSRA] bfd
[LSRA-bfd] quit
[LSRA] mpls
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[LSRA-mpls]
[LSRA-mpls]
[LSRA-mpls]
[LSRA-mpls]
4 MPLS LDP Configuration
mpls bfd-trigger fec-list tortc
mpls bfd enable
mpls bfd min-tx-interval 100 min-rx-interval 100
quit
# Enable the capability to passively create BFD sessions on LSRC.
[LSRC] bfd
[LSRC-bfd] mpls-passive
[LSRC-bfd] quit
After the configuration is complete, view the BFD session status on LSRA. You can
see that the value of the State field is Up.
Step 5 Enable IS-IS auto FRR on LSRA. View the routing information and the setup of the
backup LSP.
# Enable IS-IS auto FRR on LSRA.
[LSRA] isis
[LSRA-isis-1] frr
[LSRA-isis-1-frr] loop-free-alternate
[LSRA-isis-1-frr] quit
[LSRA-isis-1] quit
# Display information about the direct routes between LSRA and LSRC, and
between LSRA and LSRD.
[LSRA] display ip routing-table 10.1.4.0 verbose
Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------Routing Table : Public
Summary Count : 1
Destination: 10.1.4.0/24
Protocol: ISIS-L1
Process ID: 1
Preference: 15
Cost: 20
NextHop: 10.1.2.2
Neighbour: 0.0.0.0
State: Active Adv
Age: 00h05m38s
Tag: 0
Priority: medium
Label: NULL
QoSInfo: 0x0
IndirectID: 0x0
RelayNextHop: 0.0.0.0
Interface: Vlanif20
TunnelID: 0x0
Flags: D
BkNextHop: 10.1.1.2
BkInterface: Vlanif10
BkLabel: NULL
SecTunnelID: 0x0
BkPETunnelID: 0x0
BkPESecTunnelID: 0x0
BkIndirectID: 0x0
The preceding command output shows that a backup IS-IS route is generated
after IS-IS auto FRR is enabled.
# Run the display mpls lsp command on LSRA to view the LSP setup result.
[LSRA] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
1.1.1.9/32
3/NULL
-/2.2.2.9/32
NULL/3
-/Vlanif10
**LDP FRR**
/1025
/Vlanif20
2.2.2.9/32
1024/3
-/Vlanif10
**LDP FRR**
/1025
/Vlanif20
3.3.3.9/32
NULL/3
-/Vlanif20
**LDP FRR**
/1025
/Vlanif10
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3.3.3.9/32
**LDP FRR**
4.4.4.9/32
**LDP FRR**
4.4.4.9/32
**LDP FRR**
4 MPLS LDP Configuration
1025/3
-/Vlanif20
/1025
/Vlanif10
NULL/1026
-/Vlanif20
/1026
/Vlanif10
1026/1026
-/Vlanif20
/1026
/Vlanif10
The preceding command output shows that by default, the routes with 32-bit
addresses trigger the setup of a backup LSP.
Step 6 Run the lsp-trigger command on LSRC to change the LSP triggering policy so that
all routes trigger the setup of LSPs. Then check the LSP setup result.
# Run the lsp-trigger command on LSRC to change the LSP triggering policy so
that all routes trigger the setup of LSPs.
[LSRC] mpls
[LSRC-mpls] lsp-trigger all
[LSRC-mpls] quit
# Run the display mpls lsp command on LSRA to view the established LSPs.
[LSRA] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
1.1.1.9/32
3/NULL
-/2.2.2.9/32
NULL/3
-/Vlanif10
**LDP FRR**
/1025
/Vlanif20
2.2.2.9/32
1024/3
-/Vlanif10
**LDP FRR**
/1025
/Vlanif20
3.3.3.9/32
NULL/3
-/Vlanif20
**LDP FRR**
/1025
/Vlanif10
3.3.3.9/32
1025/3
-/Vlanif20
**LDP FRR**
/1025
/Vlanif10
4.4.4.9/32
NULL/1026
-/Vlanif20
**LDP FRR**
/1026
/Vlanif10
4.4.4.9/32
1026/1026
-/Vlanif20
**LDP FRR**
/1026
/Vlanif10
10.1.3.0/24
1027/3
-/Vlanif20
10.1.4.0/24
1028/3
-/Vlanif20
The preceding command output shows that the routes with 24-bit addresses
trigger the setup of LSPs.
Step 7 Configure a triggering policy to specify that all backup routes trigger the setup of
backup LSPs.
# Run the auto-frr lsp-trigger command on LSRA so that all backup routes
trigger the setup of backup LSPs.
[LSRA] mpls ldp
[LSRA-mpls-ldp] auto-frr lsp-trigger all
[LSRA-mpls-ldp] quit
Step 8 Verify the configuration.
Run the display mpls lsp command on LSRA to view the setup of backup LSPs.
[LSRA] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
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4 MPLS LDP Configuration
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
1.1.1.9/32
3/NULL
-/2.2.2.9/32
NULL/3
-/Vlanif10
**LDP FRR**
/1025
/Vlanif20
2.2.2.9/32
1024/3
-/Vlanif10
**LDP FRR**
/1025
/Vlanif20
3.3.3.9/32
NULL/3
-/Vlanif20
**LDP FRR**
/1025
/Vlanif10
3.3.3.9/32
1025/3
-/Vlanif20
**LDP FRR**
/1025
/Vlanif10
4.4.4.9/32
NULL/1026
-/Vlanif20
**LDP FRR**
/1026
/Vlanif10
4.4.4.9/32
1026/1026
-/Vlanif20
**LDP FRR**
/1026
/Vlanif10
10.1.3.0/24
1027/3
-/Vlanif20
10.1.4.0/24
1028/3
-/Vlanif20
**LDP FRR**
/1027
/Vlanif10
The preceding command output shows that the routes with 24-bit addresses
trigger the setup of LSPs.
Connect two interfaces, Port 1 and Port 2 on a tester, to LSRA and LSRD
respectively. On Port 1, inject MPLS traffic and send traffic to Port 2. Run the
shutdown command on VLANIF 20 of LSRA to simulate a fault on the primary
LSP. You can see that traffic is fast switched to the backup LSP.
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 10 20
#
bfd
#
mpls lsr-id 1.1.1.9
mpls
mpls bfd enable
mpls bfd-trigger fec-list tortc
mpls bfd min-tx-interval 100 min-rx-interval 100
#
fec-list tortc
fec-node 3.3.3.9
#
mpls ldp
auto-frr lsp-trigger all
#
isis 1
network-entity 10.0000.0000.0001.00
frr
loop-free-alternate level-1
loop-free-alternate level-2
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface Vlanif20
ip address 10.1.2.1 255.255.255.0
isis enable 1
mpls
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4 MPLS LDP Configuration
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 1.1.1.9 255.255.255.255
isis enable 1
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 10 40
#
mpls lsr-id 2.2.2.9
mpls
#
mpls ldp
#
isis 1
network-entity 10.0000.0000.0002.00
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface Vlanif40
ip address 10.1.3.1 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 40
#
interface LoopBack0
ip address 2.2.2.9 255.255.255.255
isis enable 1
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 20 30 40
#
bfd
mpls-passive
#
mpls lsr-id 3.3.3.9
mpls
lsp-trigger all
#
mpls ldp
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4 MPLS LDP Configuration
#
isis 1
network-entity 10.0000.0000.0003.00
#
interface Vlanif20
ip address 10.1.2.2 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface Vlanif30
ip address 10.1.4.1 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface Vlanif40
ip address 10.1.3.2 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 40
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack0
ip address 3.3.3.9 255.255.255.255
isis enable 1
#
return
●
LSRD configuration file
#
sysname LSRD
#
vlan batch 30
#
mpls lsr-id 4.4.4.9
mpls
#
mpls ldp
#
isis 1
network-entity 10.0000.0000.0004.00
#
interface Vlanif30
ip address 10.1.4.2 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack0
ip address 4.4.4.9 255.255.255.255
isis enable 1
#
return
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4 MPLS LDP Configuration
4.16.14 Example for Configuring an LDP Inbound Policy
Networking Requirements
On a network shown in Figure 4-27, MPLS LDP is deployed. LSRD functions as the
access device and has low performance. If the number of received labels on LSRD
is not controlled, many LSPs are established, which occupy memory resources and
cause LSRD overload. Therefore, LSRD establishes LDP LSPs with only LSRC. The
number of LSPs needs to be reduced to save LSRD memory resources.
Figure 4-27 Networking diagram for configuring the LDP inbound policy
Loopback1
Loopback1
Loopback1
1.1.1.9/32 GE0/0/1
2.2.2.9/32
GE0/0/13.3.3.9/32
GE0/0/3
GE0/0/1
10.1.2.1/24 10.1.2.2/24
10.1.1.1/24 10.1.1.2/24
VLANIF20 VLANIF20
VLANIF10 VLANIF10
LSRB
LSRA
Loopback1
4.4.4.9/32
LSRD
GE0/0/1
10.1.3.1/24
VLANIF30
GE0/0/2
10.1.3.2/24
VLANIF30
LSRC
MPLS Network
Configuration Roadmap
To meet the preceding requirements, configure an LDP inbound policy. The
configuration roadmap is as follows:
1.
Configure OSPF on LSRs to implement IP connectivity on the backbone
network.
2.
Configure local LDP sessions on the LSR so that LDP LSPs can be set up.
3.
Configure an LDP inbound policy so that the LSRD receives only Label
Mapping messages from LSRB to LSRC. This setting saves the memory of the
LSRD and saves resources.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, and configure IP addresses for
the VLANIF interfaces.
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 1
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4 MPLS LDP Configuration
[LSRA-LoopBack1] ip address 1.1.1.9 32
[LSRA-LoopBack1] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] vlan 10
[LSRA-vlan10] quit
[LSRA] interface vlanif 10
[LSRA-Vlanif10] ip address 10.1.1.1 24
[LSRA-Vlanif10] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
Step 3 Configure local LDP sessions.
# Configure LSRA.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
[LSRA] interface vlanif 10
[LSRA-Vlanif10] mpls
[LSRA-Vlanif10] mpls ldp
[LSRA-Vlanif10] quit
# Configure LSRB.
[LSRB] mpls lsr-id 2.2.2.9
[LSRB] mpls
[LSRB-mpls] quit
[LSRB] mpls ldp
[LSRB-mpls-ldp] quit
[LSRB] interface vlanif 10
[LSRB-Vlanif10] mpls
[LSRB-Vlanif10] mpls ldp
[LSRB-Vlanif10] quit
[LSRB] interface vlanif 20
[LSRB-Vlanif20] mpls
[LSRB-Vlanif20] mpls ldp
[LSRB-Vlanif20] quit
[LSRB] interface vlanif 30
[LSRB-Vlanif30] mpls
[LSRB-Vlanif30] mpls ldp
[LSRB-Vlanif30] quit
# Configure LSRC.
[LSRC] mpls lsr-id 3.3.3.9
[LSRC] mpls
[LSRC-mpls] quit
[LSRC] mpls ldp
[LSRC-mpls-ldp] quit
[LSRC] interface vlanif 20
[LSRC-Vlanif20] mpls
[LSRC-Vlanif20] mpls ldp
[LSRC-Vlanif20] quit
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4 MPLS LDP Configuration
# Configure LSRD.
[LSRD] mpls lsr-id 4.4.4.9
[LSRD] mpls
[LSRD-mpls] quit
[LSRD] mpls ldp
[LSRD-mpls-ldp] quit
[LSRD] interface vlanif 30
[LSRD-Vlanif30] mpls
[LSRD-Vlanif30] mpls ldp
[LSRD-Vlanif30] quit
# After the configuration is complete, run the display mpls lsp command on
LSRD to view the established LSP.
[LSRD] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
1.1.1.9/32
NULL/1024
-/Vlanif30
1.1.1.9/32
1024/1024
-/Vlanif30
2.2.2.9/32
NULL/3
-/Vlanif30
2.2.2.9/32
1025/3
-/Vlanif30
3.3.3.9/32
NULL/1025
-/Vlanif30
3.3.3.9/32
1026/1025
-/Vlanif30
4.4.4.9/32
3/NULL
-/-
The command output shows that the LSPs from LSRD to LSRA, LSRB, and LSRC are
established.
Step 4 Configure an LDP inbound policy.
# Configure an IP prefix list on LSRD to allow only routes to LSRC to pass.
[LSRD] ip ip-prefix prefix1 permit 3.3.3.9 32
# Configure the LDP inbound policy on LSRD so that LSRC accepts only Label
Mapping messages from LSRD.
[LSRD] mpls ldp
[LSRD-mpls-ldp] inbound peer 2.2.2.9 fec ip-prefix prefix1
[LSRD-mpls-ldp] quit
Step 5 Verify the configuration.
# Run the display mpls lsp command on LSRD to view the established LSP to
LSRC.
[LSRD] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
3.3.3.9/32
NULL/1025
-/Vlanif30
3.3.3.9/32
1026/1025
-/Vlanif30
4.4.4.9/32
3/NULL
-/-
----End
Configuration Files
●
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LSRA configuration file
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4 MPLS LDP Configuration
#
sysname LSRA
#
vlan batch 10
#
mpls lsr-id 1.1.1.9
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 10.1.1.0 0.0.0.255
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 10 20 30
#
mpls lsr-id 2.2.2.9
mpls
#
mpls ldp
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif20
ip address 10.1.2.1 255.255.255.0
mpls
mpls ldp
#
interface Vlanif30
ip address 10.1.3.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack1
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4 MPLS LDP Configuration
ip address 2.2.2.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.1.2.0 0.0.0.255
network 10.1.3.0 0.0.0.255
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 20
#
mpls lsr-id 3.3.3.9
mpls
#
mpls ldp
#
interface Vlanif20
ip address 10.1.2.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 10.1.2.0 0.0.0.255
#
return
●
LSRD configuration file
#
sysname LSRD
#
vlan batch 30
#
mpls lsr-id 4.4.4.9
mpls
#
mpls ldp
inbound peer 2.2.2.9 fec ip-prefix prefix1
#
interface Vlanif30
ip address 10.1.3.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack1
ip address 4.4.4.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 4.4.4.9 0.0.0.0
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4 MPLS LDP Configuration
network 10.1.3.0 0.0.0.255
#
ip ip-prefix prefix1 index 10 permit 3.3.3.9 32
#
return
4.16.15 Example for Configuring LDP Authentication
Networking Requirements
On the network shown in Figure 4-28, LDP sessions between PE_1 and the P and
between PE_2 and the P are established. LDP LSPs are to be established over the
LDP sessions. As the user network connected to PE_1 and PE_2 transmits
important services, the LDP sessions between PE_1 and the P and between PE_2
and the P have high security requirements.
Figure 4-28 Networking diagram for LDP authentication
Loopback1
1.1.1.9/32
CE_1
PE_1
GE0/0/1
VLANIF100
172.1.1.1/24
GE0/0/1
VLANIF100
172.1.1.2/24
Loopback1
3.3.3.9/32
CE_2
GE0/0/1
VLANIF200
172.2.1.2/24
Loopback1
2.2.2.9/32
P
GE0/0/2
VLANIF200
172.2.1.1/24
IP/MPLS
backbone
network
PE_2
Configuration Roadmap
To meet the security requirements of LDP sessions, configure LDP keychain
authentication between PE_1 and the P and between PE_2 and the P. The
configuration roadmap is as follows:
1.
Configure OSPF between the PEs and P to implement IP connectivity on the
backbone network.
2.
Configure local LDP sessions on PEs and P so that LDP LSPs can be set up to
transmit network services.
3.
Configure LDP keychain authentication between PE_1 and the P and between
PE_2 and the P to meet high security requirements.
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4 MPLS LDP Configuration
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
# Configure PE_1. The configurations of P, and PE_2 are similar to the
configuration of PE_1, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname PE_1
[PE_1] interface loopback 1
[PE_1-LoopBack1] ip address 1.1.1.9 32
[PE_1-LoopBack1] quit
[PE_1] vlan batch 100
[PE_1] interface vlanif 100
[PE_1-Vlanif100] ip address 172.1.1.1 24
[PE_1-Vlanif100] quit
[PE_1] interface gigabitethernet 0/0/1
[PE_1-GigabitEthernet0/0/1] port link-type trunk
[PE_1-GigabitEthernet0/0/1] port trunk allow-pass vlan 100
[PE_1-GigabitEthernet0/0/1] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure PE_1. The configurations of P, and PE_2 are similar to the
configuration of PE_1, and are not mentioned here.
[PE_1] ospf 1
[PE_1-ospf-1] area 0
[PE_1-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[PE_1-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[PE_1-ospf-1-area-0.0.0.0] quit
[PE_1-ospf-1] quit
After the configuration is complete, run the display ip routing-table command
on each node, and you can view that the nodes learn routes from each other.
Step 3 Configure local LDP sessions.
# Configure PE_1. The configurations of P, and PE_2 are similar to the
configuration of PE_1, and are not mentioned here.
[PE_1] mpls lsr-id 1.1.1.9
[PE_1] mpls
[PE_1-mpls] quit
[PE_1] mpls ldp
[PE_1-mpls-ldp] quit
[PE_1] interface vlanif 100
[PE_1-Vlanif100] mpls
[PE_1-Vlanif100] mpls ldp
[PE_1-Vlanif100] quit
Step 4 Configure keychain.
# Configure PE_1.
[PE_1] keychain kforldp1 mode periodic weekly
[PE_1-keychain-kforldp1] tcp-kind 180
[PE_1-keychain-kforldp1] tcp-algorithm-id sha-256 8
[PE_1-keychain-kforldp1] receive-tolerance 15
[PE_1-keychain-kforldp1] key-id 1
[PE_1-keychain-kforldp1-keyid-1] algorithm sha-256
[PE_1-keychain-kforldp1-keyid-1] key-string cipher huaweiwork
[PE_1-keychain-kforldp1-keyid-1] send-time day mon to thu
[PE_1-keychain-kforldp1-keyid-1] receive-time day mon to thu
[PE_1-keychain-kforldp1-keyid-1] quit
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[PE_1-keychain-kforldp1] key-id 2
[PE_1-keychain-kforldp1-keyid-2] algorithm sha-256
[PE_1-keychain-kforldp1-keyid-2] key-string cipher testpass
[PE_1-keychain-kforldp1-keyid-2] send-time day fri to sun
[PE_1-keychain-kforldp1-keyid-2] receive-time day fri to sun
[PE_1-keychain-kforldp1-keyid-2] quit
[PE_1-keychain-kforldp1] quit
# Configure the P.
[P] keychain kforldp1 mode periodic weekly
[P-keychain-kforldp1] tcp-kind 180
[P-keychain-kforldp1] tcp-algorithm-id sha-256 8
[P-keychain-kforldp1] receive-tolerance 15
[P-keychain-kforldp1] key-id 1
[P-keychain-kforldp1-keyid-1] algorithm sha-256
[P-keychain-kforldp1-keyid-1] key-string cipher huaweiwork
[P-keychain-kforldp1-keyid-1] send-time day mon to thu
[P-keychain-kforldp1-keyid-1] receive-time day mon to thu
[P-keychain-kforldp1-keyid-1] quit
[P-keychain-kforldp1] key-id 2
[P-keychain-kforldp1-keyid-2] algorithm sha-256
[P-keychain-kforldp1-keyid-2] key-string cipher testpass
[P-keychain-kforldp1-keyid-2] send-time day fri to sun
[P-keychain-kforldp1-keyid-2] receive-time day fri to sun
[P-keychain-kforldp1-keyid-2] quit
[P-keychain-kforldp1] quit
Step 5 Configure LDP keychain authentication.
# Configure PE_1.
[PE_1] mpls ldp
[PE_1-mpls-ldp] authentication key-chain peer 2.2.2.9 name kforldp1
[PE_1-mpls-ldp] quit
# Configure the P.
[P] mpls ldp
[P-mpls-ldp] authentication key-chain peer 1.1.1.9 name kforldp1
[P-mpls-ldp] quit
Step 6 Configure keychain.
# Configure PE_2.
[PE_2] keychain kforldp2 mode periodic weekly
[PE_2-keychain-kforldp2] tcp-kind 180
[PE_2-keychain-kforldp2] tcp-algorithm-id sha-256 8
[PE_2-keychain-kforldp2] receive-tolerance 15
[PE_2-keychain-kforldp2] key-id 1
[PE_2-keychain-kforldp2-keyid-1] algorithm sha-256
[PE_2-keychain-kforldp2-keyid-1] key-string cipher huaweiwork
[PE_2-keychain-kforldp2-keyid-1] send-time day mon to thu
[PE_2-keychain-kforldp2-keyid-1] receive-time day mon to thu
[PE_2-keychain-kforldp2-keyid-1] quit
[PE_2-keychain-kforldp2] key-id 2
[PE_2-keychain-kforldp2-keyid-2] algorithm sha-256
[PE_2-keychain-kforldp2-keyid-2] key-string cipher testpass
[PE_2-keychain-kforldp2-keyid-2] send-time day fri to sun
[PE_2-keychain-kforldp2-keyid-2] receive-time day fri to sun
[PE_2-keychain-kforldp2-keyid-2] quit
[PE_2-keychain-kforldp2] quit
# Configure the P.
[P] keychain kforldp2 mode periodic weekly
[P-keychain-kforldp2] tcp-kind 180
[P-keychain-kforldp2] tcp-algorithm-id sha-256 8
[P-keychain-kforldp2] receive-tolerance 15
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[P-keychain-kforldp2] key-id 1
[P-keychain-kforldp2-keyid-1] algorithm sha-256
[P-keychain-kforldp2-keyid-1] key-string cipher huaweiwork
[P-keychain-kforldp2-keyid-1] send-time day mon to thu
[P-keychain-kforldp2-keyid-1] receive-time day mon to thu
[P-keychain-kforldp2-keyid-1] quit
[P-keychain-kforldp2] key-id 2
[P-keychain-kforldp2-keyid-2] algorithm sha-256
[P-keychain-kforldp2-keyid-2] key-string cipher testpass
[P-keychain-kforldp2-keyid-2] send-time day fri to sun
[P-keychain-kforldp2-keyid-2] receive-time day fri to sun
[P-keychain-kforldp2-keyid-2] quit
[P-keychain-kforldp2] quit
Step 7 Configure LDP keychain authentication.
# Configure PE_2.
[PE_2] mpls ldp
[PE_2-mpls-ldp] authentication key-chain peer 2.2.2.9 name kforldp2
[PE_2-mpls-ldp] quit
# Configure the P.
[P] mpls ldp
[P-mpls-ldp] authentication key-chain peer 3.3.3.9 name kforldp2
[P-mpls-ldp] quit
Step 8 Verify the configuration.
# Run the display mpls ldp session verbose command on the P. You can see that
LDP keychain authentication and referenced keychain names are configured in the
LDP sessions between PE_1 and the P and between PE_2 and the P.
[P] display mpls ldp session verbose
LDP Session(s) in Public Network
-----------------------------------------------------------------------------Peer LDP ID
: 1.1.1.9:0
Local LDP ID : 2.2.2.9:0
TCP Connection : 2.2.2.9 -> 1.1.1.9
Session State : Operational
Session Role : Active
MD5 Flag
: Off
Session FT Flag : Off
Reconnect Timer : --Recovery Timer : --Keychain Name : kforldp1
Authentication applied: Peer
Negotiated Keepalive Hold Timer : 45 Sec
Configured Keepalive Send Timer : --Keepalive Message Sent/Rcvd
: 19/19 (Message Count)
Label Advertisement Mode
: Downstream Unsolicited
Label Resource Status(Peer/Local) : Available/Available
Session Age
: 0000:00:04 (DDDD:HH:MM)
Session Deletion Status
: No
Capability:
Capability-Announcement
mLDP P2MP Capability
mLDP MP2MP Capability
mLDP MBB Capability
: Off
: Off
: Off
: Off
Outbound&Inbound Policies applied : NULL
Addresses received from peer: (Count: 2)
1.1.1.9
172.1.1.1
-----------------------------------------------------------------------------Peer LDP ID
: 3.3.3.9:0
Local LDP ID : 2.2.2.9:0
TCP Connection : 2.2.2.9 <- 3.3.3.9
Session State : Operational
Session Role : Active
MD5 Flag
: Off
Session FT Flag : Off
Reconnect Timer : --Recovery Timer : ---
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Keychain Name : kforldp2
Authentication applied: Peer
Negotiated Keepalive Hold Timer : 45 Sec
Configured Keepalive Send Timer : --Keepalive Message Sent/Rcvd
: 18/18 (Message Count)
Label Advertisement Mode
: Downstream Unsolicited
Label Resource Status(Peer/Local) : Available/Available
Session Age
: 0000:00:04 (DDDD:HH:MM)
Session Deletion Status
: No
Capability:
Capability-Announcement
mLDP P2MP Capability
mLDP MP2MP Capability
mLDP MBB Capability
: Off
: Off
: Off
: Off
Outbound&Inbound Policies applied : NULL
Addresses received from peer: (Count: 2)
3.3.3.9
172.2.1.2
------------------------------------------------------------------------------
----End
Configuration Files
●
PE_1 configuration file
#
sysname PE_1
#
vlan batch 100
#
mpls lsr-id 1.1.1.9
mpls
#
mpls ldp
authentication key-chain peer 2.2.2.9 name kforldp1
#
keychain kforldp1 mode periodic weekly
receive-tolerance 15
tcp-kind 180
key-id 1
algorithm sha-256
key-string cipher %^%#RHk(LEvyUBmkls=i(>8L9i=M!}mM4FCvcuVu&@-G%^%#
send-time day mon to thu
receive-time day mon to thu
key-id 2
algorithm sha-256
key-string cipher %^%#="+W)uY+N$8',5Lhem%H4ZyT@h{24%Lm6A'HAnS!%^%#
send-time day fri to sun
receive-time day fri to sun
#
interface Vlanif100
ip address 172.1.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.9 0.0.0.0
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network 172.1.1.0 0.0.0.255
#
return
●
P configuration file
#
sysname P
#
vlan batch 100 200
#
mpls lsr-id 2.2.2.9
mpls
#
mpls ldp
authentication key-chain peer 1.1.1.9 name kforldp1
authentication key-chain peer 3.3.3.9 name kforldp2
#
keychain kforldp1 mode periodic weekly
receive-tolerance 15
tcp-kind 180
key-id 1
algorithm sha-256
key-string cipher %^%#Se}$HiYed".qRuT,/=~2X47R:*Yl,Nx5&[8_p$kP%^%#
send-time day mon to thu
receive-time day mon to thu
key-id 2
algorithm sha-256
key-string cipher %^%#vse|>n^<W6R&=p20J7*8'7'+KTBI8Rs_eX7#'Q_<%^%#
send-time day fri to sun
receive-time day fri to sun
#
keychain kforldp2 mode periodic weekly
receive-tolerance 15
tcp-kind 180
key-id 1
algorithm sha-256
key-string cipher %^%#WTl)$zT5!X#LH[~.zr9Y@8k#<h"wF)pJLv"!U~A1%^%#
send-time day mon to thu
receive-time day mon to thu
key-id 2
algorithm sha-256
key-string cipher %^%#:N6U5oq@^+,c0P/mh,OC&P}r3_L)~N8~2IXq5$iP%^%#
send-time day fri to sun
receive-time day fri to sun
#
interface Vlanif100
ip address 172.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif200
ip address 172.2.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 200
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 172.1.1.0 0.0.0.255
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network 172.2.1.0 0.0.0.255
#
return
●
PE_2 configuration file
#
sysname PE_2
#
vlan batch 200
#
mpls lsr-id 3.3.3.9
mpls
#
mpls ldp
authentication key-chain peer 2.2.2.9 name kforldp2
#
keychain kforldp2 mode periodic weekly
receive-tolerance 15
tcp-kind 180
key-id 1
algorithm sha-256
key-string cipher %^%#]~3=Y;alm>(cdcV<;`+O1}M`0Pd!GKCb#<9S+ovC%^%#
send-time day mon to thu
receive-time day mon to thu
key-id 2
algorithm sha-256
key-string cipher %^%#C$UBYKU7=,:(\iI_3dyH^C#5Trq~wRQc.3I$&Hj*%^%#
send-time day fri to sun
receive-time day fri to sun
#
interface Vlanif200
ip address 172.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 200
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 172.2.1.0 0.0.0.255
#
return
4.16.16 Example for Configuring LDP GTSM
Networking Requirements
On an MPLS network shown in Figure 4-29, MPLS and MPLS LDP run between
every two nodes. Attackers may simulate LDP unicast packets and send the
packets to LSRB. LSRB becomes busy processing these packets, causing high CPU
usage. The preceding problems need to be addressed to protect nodes and
enhance system security.
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Figure 4-29 Networking diagram for configuring LDP GTSM
Loopback0
Loopback0
Loopback0
1.1.1.1/32
2.2.2.2/32
3.3.3.3/32
GE0/0/1
GE0/0/1
GE0/0/1
GE0/0/2
10.1.1.1/24 10.1.1.2/24
10.2.1.1/24 10.2.1.2/24
VLANIF10
LSRA
VLANIF10
VLANIF20 VLANIF20
LSRB
LSRC
Configuration Roadmap
To meet the preceding requirements, configure LDP GTSM. The configuration
roadmap is as follows:
1.
Configure OSPF on LSRs to implement IP connectivity on the backbone
network.
2.
Enable MPLS and MPLS LDP globally and interfaces of LSRs.
3.
Configure the LDP GTSM function on LSRs and set the TTL range.
Procedure
Step 1 Create VLANs and VLANIF interfaces on the switch, configure IP addresses for the
VLANIF interfaces, and add physical interfaces to the VLANs.
# Configure LSRA. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 0
[LSRA-LoopBack0] ip address 1.1.1.1 32
[LSRA-LoopBack0] quit
[LSRA] vlan batch 10
[LSRA] interface vlanif 10
[LSRA-Vlanif10] ip address 10.1.1.1 24
[LSRA-Vlanif10] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
Step 2 Configure OSPF to advertise the network segments connecting to interfaces on
each node and to advertise the routes of hosts with LSR IDs.
# Configure LSRA.
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.1 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
# Configure LSRB.
[LSRB] ospf 1
[LSRB-ospf-1] area 0
[LSRB-ospf-1-area-0.0.0.0] network 2.2.2.2 0.0.0.0
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[LSRB-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
[LSRB-ospf-1-area-0.0.0.0] network 10.2.1.0 0.0.0.255
[LSRB-ospf-1-area-0.0.0.0] quit
[LSRB-ospf-1] quit
# Configure LSRC.
[LSRC] ospf 1
[LSRC-ospf-1] area 0
[LSRC-ospf-1-area-0.0.0.0] network 3.3.3.3 0.0.0.0
[LSRC-ospf-1-area-0.0.0.0] network 10.2.1.0 0.0.0.255
[LSRC-ospf-1-area-0.0.0.0] quit
[LSRC-ospf-1] quit
After the configuration is complete, run the display ip routing-table command
on each node, and you can view that the nodes learn routes from each other.
Step 3 Enable MPLS and MPLS LDP on each node and each interface of nodes.
# Configure LSRA. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] mpls lsr-id 1.1.1.1
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
[LSRA] interface vlanif 10
[LSRA-Vlanif10] mpls
[LSRA-Vlanif10] mpls ldp
[LSRA-Vlanif10] quit
After the configuration is complete, run the display mpls ldp session command
on each node to view the established LDP session. LSRA is used as an example.
[LSRA] display mpls ldp session
LDP Session(s) in Public Network
Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDDD:HH:MM)
A '*' before a session means the session is being deleted.
-----------------------------------------------------------------------------PeerID
Status
LAM SsnRole SsnAge
KASent/Rcv
-----------------------------------------------------------------------------2.2.2.2:0
Operational DU Passive 0000:00:02 9/9
-----------------------------------------------------------------------------TOTAL: 1 session(s) Found.
Step 4 Configure LDP GTSM.
# On LSRA, configure the TTL values carried in LDP packets received from LSRB to
range from 253 to 255.
[LSRA] mpls ldp
[LSRA-mpls-ldp] gtsm peer 2.2.2.2 valid-ttl-hops 3
[LSRA-mpls-ldp] quit
# On LSRB, configure the TTL values carried in the LDP packets received from
LSRA to range from 252 to 255, and the TTL values carried in LDP packets
received from LSRC to range from 251 to 255.
[LSRB] mpls ldp
[LSRB-mpls-ldp] gtsm peer 1.1.1.1 valid-ttl-hops 4
[LSRB-mpls-ldp] gtsm peer 3.3.3.3 valid-ttl-hops 5
[LSRB-mpls-ldp] quit
# On LSRC, configure the TTL values carried in LDP packets received from LSRB to
range from 250 to 255.
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[LSRC] mpls ldp
[LSRC-mpls-ldp] gtsm peer 2.2.2.2 valid-ttl-hops 6
[LSRC-mpls-ldp] quit
If a host simulates the LDP packets of LSRA to attack LSRB, LSRB directly discards
the packets because the TTL values carried in the LDP packets are beyond the
range of 252 to 255. In the GTSM statistics on LSRB, the number of discarded
packets increases.
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 10
#
mpls lsr-id 1.1.1.1
mpls
#
mpls ldp
gtsm peer 2.2.2.2 valid-ttl-hops 3
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.1 0.0.0.0
network 10.1.1.0 0.0.0.255
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 10 20
#
mpls lsr-id 2.2.2.2
mpls
#
mpls ldp
gtsm peer 1.1.1.1 valid-ttl-hops 4
gtsm peer 3.3.3.3 valid-ttl-hops 5
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
mpls
mpls ldp
#
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interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 2.2.2.2 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.2 0.0.0.0
network 10.1.1.0 0.0.0.255
network 10.2.1.0 0.0.0.255
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 20
#
mpls lsr-id 3.3.3.3
mpls
#
mpls ldp
gtsm peer 2.2.2.2 valid-ttl-hops 6
#
interface Vlanif20
ip address 10.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 3.3.3.3 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.3 0.0.0.0
network 10.2.1.0 0.0.0.255
#
return
4.16.17 Example for Configuring LDP Extension for Inter-Area
LSP
Networking Requirements
On a large network, multiple IGP areas need to be configured for flexible network
deployment and fast route convergence. When advertising routes between IGP
areas, to prevent a large number of routes from consuming too many resources,
an Area Border Router (ABR) needs to aggregate the routes in the area and
advertises the aggregated route to the neighboring IGP areas. By default, when
establishing LSPs, LDP searches the routing table for the route that exactly
matches the FEC in the received Label Mapping message. If the route is an
aggregated route, LDP establishes only a liberal LSP, not an inter-area LSP.
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As shown in Figure 4-30, IS-IS runs between devices. Two IGP areas Area 10 and
Area 20 exist. LSRD aggregates routes from LSRB and LSRC and sends the
aggregated route to Area 20. Two inter-area LSPs need to be established: one is
from LSRA to LSRB and the other is from LSRA to LSRC.
Figure 4-30 Networking diagram for configuring LDP extension for inter-area LSP
Loopback0
1.3.0.1/32
Loopback0
1.1.0.1/32 GE0/0/1
10.1.1.1/24
VLANIF10
LSRA
IS-IS
Area20
/3
0/0 /24
E
1
Loopback0 G .1.1 0
/0/ /24 LSRB
3
0
1
.
F
1.2.0.1/32 20 NI
GE .1.2 30
A
VL G
0.1 NIF
IS-IS
20 E0/ 2 LA
.1. 0/2 V
Area10
VL 2.
GE0/0/1
AN 1/2
IF2 4
10.1.1.2/24 LSRD
Loopback0
0
VLANIF10
1.3.0.2/32
G
20 E0/
0
.
VL 1.2. /1
2
AN /2
IF2 4
0
LSRC
Configuration Roadmap
To meet the preceding requirements, configure LDP extension for inter-area LSP.
The configuration roadmap is as follows:
1.
Configure IS-IS on LSRs to implement IP connectivity on the backbone
network.
2.
Enable MPLS and MPLS LDP globally and interfaces of LSRs.
3.
Configure LDP extension for inter-area LSP on LSRA to enable LDP to search
for a route according to the longest match rule to establish an LDP LSP.
Procedure
Step 1 On the switches, create VLANs and VLANIF interfaces, configure IP addresses for
the VLANIF interfaces, and add physical interfaces to VLANs.
# Configure LSRA. The configurations of LSRB, LSRC, and LSRD are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] interface loopback 0
[LSRA-LoopBack0] ip address 1.1.0.1 32
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[LSRA-LoopBack0] quit
[LSRA] vlan batch 10
[LSRA] interface vlanif 10
[LSRA-Vlanif10] ip address 10.1.1.1 24
[LSRA-Vlanif10] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[LSRA-GigabitEthernet0/0/1] quit
Step 2 Configure basic IS-IS functions.
# Configure LSRA.
[LSRA] isis 1
[LSRA-isis-1] is-level level-2
[LSRA-isis-1] network-entity 20.0010.0100.0001.00
[LSRA-isis-1] quit
[LSRA] interface vlanif 10
[LSRA-Vlanif10] isis enable 1
[LSRA-Vlanif10] quit
[LSRA] interface loopback 0
[LSRA-LoopBack0] isis enable 1
[LSRA-LoopBack0] quit
# Configure LSRD.
[LSRD] isis 1
[LSRD-isis-1] network-entity 10.0010.0200.0001.00
[LSRD-isis-1] quit
[LSRD] interface vlanif 10
[LSRD-Vlanif10] isis enable 1
[LSRD-Vlanif10] isis circuit-level level-2
[LSRD-Vlanif10] quit
[LSRD] interface vlanif 20
[LSRD-Vlanif20] isis enable 1
[LSRD-Vlanif20] isis circuit-level level-1
[LSRD-Vlanif20] quit
[LSRD] interface vlanif 30
[LSRD-Vlanif30] isis enable 1
[LSRD-Vlanif30] isis circuit-level level-1
[LSRD-Vlanif30] quit
[LSRD] interface loopback 0
[LSRD-LoopBack0] isis enable 1
[LSRD-LoopBack0] quit
# Configure LSRB.
[LSRB] isis 1
[LSRB-isis-1] is-level level-1
[LSRB-isis-1] network-entity 10.0010.0300.0001.00
[LSRB-isis-1] quit
[LSRB] interface vlanif 30
[LSRB-Vlanif30] isis enable 1
[LSRB-Vlanif30] quit
[LSRB] interface loopback 0
[LSRB-LoopBack0] isis enable 1
[LSRB-LoopBack0] quit
# Configure LSRC.
[LSRC] isis 1
[LSRC-isis-1] is-level level-1
[LSRC-isis-1] network-entity 10.0010.0300.0002.00
[LSRC-isis-1] quit
[LSRC] interface vlanif 20
[LSRC-Vlanif20] isis enable 1
[LSRC-Vlanif20] quit
[LSRC] interface loopback 0
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[LSRC-LoopBack0] isis enable 1
[LSRC-LoopBack0] quit
# Run the display ip routing-table command on LSRA to check routing
information.
[LSRA] display ip routing-table
Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------Routing Tables: Public
Destinations : 10
Routes : 10
Destination/Mask
Proto
1.1.0.1/32 Direct
1.2.0.1/32 ISIS-L2
1.3.0.1/32 ISIS-L2
1.3.0.2/32 ISIS-L2
10.1.1.0/24 Direct
10.1.1.1/32 Direct
20.1.1.0/24 ISIS-L2
20.1.2.0/24 ISIS-L2
127.0.0.0/8 Direct
127.0.0.1/32 Direct
0
15
15
15
0
0
15
15
0
0
Pre Cost
0
10
20
20
0
0
20
20
0
0
Flags NextHop
D 127.0.0.1
D 10.1.1.2
D 10.1.1.2
D 10.1.1.2
D 10.1.1.1
D 127.0.0.1
D 10.1.1.2
D 10.1.1.2
D 127.0.0.1
D 127.0.0.1
Interface
LoopBack0
Vlanif10
Vlanif10
Vlanif10
Vlanif10
Vlanif10
Vlanif10
Vlanif10
InLoopBack0
InLoopBack0
Step 3 Configure a policy for generating the aggregated route.
# Run the summary command on LSRD to aggregate host routes that are
destined for LSRB and LSRC.
[LSRD] isis 1
[LSRD-isis-1] summary 1.3.0.0 255.255.255.0 avoid-feedback
[LSRD-isis-1] quit
# Run the display ip routing-table command on LSRA to check routing
information.
[LSRA] display ip routing-table
Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------Routing Tables: Public
Destinations : 9
Routes : 9
Destination/Mask
Proto Pre Cost
1.1.0.1/32 Direct
1.2.0.1/32 ISIS-L2
1.3.0.0/24 ISIS-L2
10.1.1.0/24 Direct
10.1.1.1/32 Direct
20.1.1.0/24 ISIS-L2
20.1.2.0/24 ISIS-L2
127.0.0.0/8 Direct
127.0.0.1/32 Direct
0 0
15 10
15 20
0 0
0 0
15 20
15 20
0 0
0 0
Flags NextHop
D 127.0.0.1
D 10.1.1.2
D 10.1.1.2
D 10.1.1.1
D 127.0.0.1
D 10.1.1.2
D 10.1.1.2
D 127.0.0.1
D 127.0.0.1
Interface
LoopBack0
Vlanif10
Vlanif10
Vlanif10
Vlanif10
Vlanif10
Vlanif10
InLoopBack0
InLoopBack0
The command output shows that host routes that are destined for LSRB and LSRC
are aggregated.
Step 4 Configure global and interface-based MPLS and MPLS LDP on each node so that
the network can forward MPLS traffic. Then check the LSP setup result.
# Configure LSRA.
[LSRA] mpls lsr-id 1.1.0.1
[LSRA] mpls
[LSRA-mpls] quit
[LSRA] mpls ldp
[LSRA-mpls-ldp] quit
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[LSRA] interface vlanif 10
[LSRA-Vlanif10] mpls
[LSRA-Vlanif10] mpls ldp
[LSRA-Vlanif10] quit
# Configure LSRD.
[LSRD] mpls lsr-id 1.2.0.1
[LSRD] mpls
[LSRD-mpls] quit
[LSRD] mpls ldp
[LSRD-mpls-ldp] quit
[LSRD] interface vlanif 10
[LSRD-Vlanif10] mpls
[LSRD-Vlanif10] mpls ldp
[LSRD-Vlanif10] quit
[LSRD] interface vlanif 20
[LSRD-Vlanif20] mpls
[LSRD-Vlanif20] mpls ldp
[LSRD-Vlanif20] quit
[LSRD] interface vlanif 30
[LSRD-Vlanif30] mpls
[LSRD-Vlanif30] mpls ldp
[LSRD-Vlanif30] quit
# Configure LSRB.
[LSRB] mpls lsr-id 1.3.0.1
[LSRB] mpls
[LSRB-mpls] quit
[LSRB] mpls ldp
[LSRB-mpls-ldp] quit
[LSRB] interface vlanif 30
[LSRB-Vlanif30] mpls
[LSRB-Vlanif30] mpls ldp
[LSRB-Vlanif30] quit
# Configure LSRC.
[LSRC] mpls lsr-id 1.3.0.2
[LSRC] mpls
[LSRC-mpls] quit
[LSRC] mpls ldp
[LSRC-mpls-ldp] quit
[LSRC] interface vlanif 20
[LSRC-Vlanif20] mpls
[LSRC-Vlanif20] mpls ldp
[LSRC-Vlanif20] quit
# After the configuration is complete, run the display mpls lsp command on LSRA
to view the established LSP.
[LSRA] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
1.2.0.1/32
NULL/3
-/Vlanif10
1.2.0.1/32
1024/3
-/Vlanif10
1.1.0.1/32
3/NULL
-/-
The command output shows that by default, LDP does not establish the inter-area
LSPs from LSRA to LSRB and from LSRA to LSRC.
Step 5 Configure LDP extensions for inter-area LSPs.
# Run the longest-match command on LSRA to configure LDP to search for a
route according to the longest match rule to establish an inter-area LDP LSP.
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[LSRA] mpls ldp
[LSRA-mpls-ldp] longest-match
[LSRA-mpls-ldp] quit
Step 6 Verify the configuration.
# Run the display mpls lsp command on LSRA to view the established LSP.
[LSRA] display mpls lsp
Flag after Out IF: (I) - LSP Is Only Iterated by RLFA
------------------------------------------------------------------------------LSP Information: LDP LSP
------------------------------------------------------------------------------FEC
In/Out Label In/Out IF
Vrf Name
1.2.0.1/32
NULL/3
-/Vlanif10
1.2.0.1/32
1024/3
-/Vlanif10
1.3.0.1/32
NULL/1025
-/Vlanif10
1.3.0.1/32
1025/1025
-/Vlanif10
1.3.0.2/32
NULL/1026
-/Vlanif10
1.3.0.2/32
1026/1026
-/Vlanif10
1.1.0.1/32
3/NULL
-/-
The command output shows that LDP establishes the inter-area LSPs from LSRA to
LSRB and from LSRA to LSRC.
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 10
#
mpls lsr-id 1.1.0.1
mpls
#
mpls ldp
longest-match
#
isis 1
is-level level-2
network-entity 20.0010.0100.0001.00
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface LoopBack0
ip address 1.1.0.1 255.255.255.255
isis enable 1
#
return
●
LSRD configuration file
#
sysname LSRD
#
vlan batch 10 20 30
#
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mpls lsr-id 1.2.0.1
mpls
#
mpls ldp
#
isis 1
network-entity 10.0010.0200.0001.00
summary 1.3.0.0 255.255.255.0 avoid-feedback
#
interface Vlanif10
ip address 10.1.1.2 255.255.255.0
isis enable 1
isis circuit-level level-2
mpls
mpls ldp
#
interface Vlanif20
ip address 20.1.2.1 255.255.255.0
isis enable 1
isis circuit-level level-1
mpls
mpls ldp
#
interface Vlanif30
ip address 20.1.1.1 255.255.255.0
isis enable 1
isis circuit-level level-1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 1.2.0.1 255.255.255.255
isis enable 1
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 30
#
mpls lsr-id 1.3.0.1
mpls
#
mpls ldp
#
isis 1
is-level level-1
network-entity 10.0010.0300.0001.00
#
interface Vlanif30
ip address 20.1.1.2 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
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port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack0
ip address 1.3.0.1 255.255.255.255
isis enable 1
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 20
#
mpls lsr-id 1.3.0.2
mpls
#
mpls ldp
#
isis 1
is-level level-1
network-entity 10.0010.0300.0002.00
#
interface Vlanif20
ip address 20.1.2.2 255.255.255.0
isis enable 1
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
interface LoopBack0
ip address 1.3.0.2 255.255.255.255
isis enable 1
#
return
4.17 Troubleshooting MPLS LDP
4.17.1 LDP Session Alternates Between Up and Down States
Fault Description
An LDP session alternates between Up and Down states when you add, change, or
delete the LDP GR timer, LDP MTU, LDP authentication, LDP Keepalive timer, or
LDP transport address.
Procedure
Step 1 Run the display this command in the LDP view to check whether LDP GR or LDP
MTU is configured.
●
If the following information is displayed:
mpls ldp
graceful-restart
LDP GR is configured.
●
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mpls ldp
mtu-signalling apply-tlv
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LDP MTU is configured.
●
If information similar to the following is displayed:
mpls ldp
md5-password cipher 2.2.2.2 %^%#="+W)uY+N$8',5Lhem%H4ZyT@h{24%Lm6A'HAnS!%^%#
or
mpls ldp
authentication key-chain peer 2.2.2.2 name kc1
LDP authentication is configured.
Step 2 Run the display this command in the interface view to check whether the LDP
Keepalive timer or LDP transport address is configured.
●
If information similar to the following is displayed:
mpls ldp
mpls ldp timer keepalive-hold 30
The LDP Keepalive timer is configured.
●
If information similar to the following is displayed:
mpls ldp
mpls ldp transport-address interface
The LDP transport address is configured.
Step 3 After the preceding configurations are complete, wait for 10s and the LDP session
becomes stable.
----End
4.17.2 LDP Session Is Down
Fault Description
An LDP session is Down after being established.
Procedure
Step 1 Check whether the interface where the LDP session is established is shut down.
Run the display this command in the interface view. If the following information
is displayed:
shutdown
The interface is shut down.
If the interface is shut down, run the undo shutdown command to start the
interface.
Step 2 Check whether the MPLS-related configurations are deleted.
Run the display current-configuration command in any view to check whether
MPLS-related configurations exist.
●
If the output does not include the following information:
mpls
The MPLS configuration is deleted.
●
If the output does not include the following information:
mpls ldp
The MPLS LDP configuration is deleted.
●
If the output does not include the following information:
mpls ldp remote-peer
The remote LDP session is deleted.
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If MPLS-related configurations are deleted, run the corresponding commands to
restore the configurations.
----End
4.17.3 LDP LSP Alternates Between Up and Down States
Fault Description
An LDP LSP alternates between Up and Down states after being established.
Procedure
●
Check whether the LDP session flaps.
Run the display mpls ldp session command to check the displayed Status
field. You are advised to run this command once every 1s. If the LDP session
status switches between Operational and non-operational, the LDP session
flap occurs.
If the LDP session flap occurs, rectify the fault by referring to LDP Session
Alternates Between Up and Down States.
----End
4.17.4 LDP LSP Is Down
Fault Description
An LDP LSP is Down after being established.
Procedure
Step 1 Check whether the LDP session is correctly established.
Run the display mpls ldp session command to check the displayed Status field. If
LDP session status is Operational, the LDP session is established and in Up state.
If LDP session status is not Operational, the LDP session is not established.
●
If the LDP session is not established, rectify the fault by referring to LDP
Session Is Down.
Step 2 Check whether the LSP establishment policy is configured.
●
Run the display this command in the MPLS view. If information similar to the
following is displayed:
lsp-trigger ip-prefix abc
Check whether the Down LSP is filtered out based on the IP prefix list abc.
●
Run the display this command in the MPLS-LDP view. If information similar
to the following is displayed:
propagate mapping for ip-prefix abc
Check whether the Down LSP is filtered out based on the IP prefix list abc.
●
Run the display ip ip-prefix command in the system view. If information
similar to the following is displayed:
index: 10
index: 20
permit 10.1.1.1/32
permit 10.2.2.2/32
The LSP can be established only based on routes 10.1.1.1/32 and 10.2.2.2/32.
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●
4 MPLS LDP Configuration
If the preceding IP prefix list is configured, add routing information of the
Down LSP to the IP prefix list.
----End
4.17.5 Inter-Area LSP Fails to Be Established
Fault Description
An inter-area LSP fails to be established after LDP extension for inter-area LSP is
configured.
Procedure
Step 1 Check whether LDP extension for inter-area LSP is configured.
Run the display mpls ldp command to check the displayed Longest-match field.
If the field is displayed as On, LDP extension for inter-area LSP is enabled. If the
field is displayed as Off, LDP extension for inter-area LSP is disabled.
●
If LDP extension for inter-area LSP is disabled, run the longest-match
command to enable this function.
Step 2 Check whether the LDP session is correctly established.
Run the display mpls ldp session command to check the displayed Status field. If
LDP session status is Operational, the LDP session is established and in Up state.
If LDP session status is not Operational or no LDP session information is
displayed, the LDP session is not established.
●
If the LDP session is not established, locate the fault by referring to LDP
Session Is Down.
Step 3 Check whether the LDP session matches the route.
Run the display ip routing-table command to check the fields NextHop and
Interface.
Run the display mpls ldp session verbose command to check the Addresses
received from peer field.
Run the display mpls ldp peer command to check the DiscoverySource field.
If the field NextHop is contained in the field Addresses received from peer and
the values of fields Interface and DiscoverySource are the same, the LDP session
matches the route.
●
If the LDP session does not match the route, locate the fault by referring to
LDP LSP Is Down.
----End
4.18 FAQ About MPLS
4.18.1 What Information Needs to Be Collected If an MPLS
LDP Session Fails to Be Established?
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After an MPLS LDP session fails to be established, R&D personnel need to collect
the following information for analysis:
Command
Description
display mpls ldp session verbose
Displays detailed information about
the session status.
display mpls ldp peer verbose
Displays the LDP status: local or
remote.
display mpls ldp interface [verbose]
Displays sent and received LDP packets
on the interface. If MPLS LDP is
disabled on the interface, no
command output is displayed.
display mpls ldp remote-peer peername
Displays sent and received LDP
protocol packets after the remote
session is established.
display ip routing-table x.x.x.x
verbose
Displays whether the route to the peer
exists.
display fib x.x.x.x verbose
display tcp status
Displays whether the TCP connection
is in Established state.
display mpls ldp event session-down
Displays the reason for LDP Session
Down.
4.18.2 The Two Ends of an LSP Are Up and Can Send Hello
Messages, but the Peer End Cannot Receive Them. Why?
If the two ends of an LSP are Up and can send Hello messages, but the peer end
cannot receive the messages, the possible causes are as follows:
●
Devices do not support sending of large packets, for example, the device can
send packets whose maximum size is 180 bytes. To check whether the peer
end can send large packets, ping the IP address of the peer end using large
packets.
●
Run the display cpu-defend statistics slot slot-id command to check
whether Hello messages are dropped due to attack defense policies or Hello
messages do not reach the cpu-defend module.
●
Check whether statistics on MPLS-related ACL packets exist and ACLs are
correctly delivered.
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5
5 MPLS QoS Configuration
MPLS QoS Configuration
About This Chapter
This chapter describes how to configure Multiprotocol Label Switching quality of
service (MPLS QoS). On an MPLS network, MPLS QoS controls enterprise network
traffic, and implements congestion avoidance and congestion management to
reduce packet loss. In addition, MPLS QoS provides dedicated bandwidth for
enterprise users or differentiated services (such as voice, video, and data services).
5.1 Overview of MPLS QoS
5.2 Understanding MPLS QoS
5.3 Application of MPLS QoS in the VPN Service
5.4 Licensing Requirements and Limitations for MPLS QoS
5.5 Default Settings for MPLS QoS
5.6 Configuring the Mapping of the Precedence in the Public MPLS Tunnel Label
5.7 Setting the DiffServ Mode Supported by MPLS VPNs
5.8 Configuration Examples for MPLS QoS
5.1 Overview of MPLS QoS
Definition
Multiprotocol Label Switching quality of service (MPLS QoS) is implemented using
the Differentiated Services (DiffServ) model on an MPLS network. MPLS QoS
provides differentiated services to meet diverse requirements.
Purpose
MPLS uses label-based forwarding and provides powerful and flexible functions to
meet the requirements of new applications. MPLS has been widely used for
building large-scale networks and supports multiple network protocols including
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IPv4 and IPv6. On an MPLS network, however, IP QoS cannot be used to
guarantee quality of services, so MPLS QoS is used instead.
Similar to IP QoS, MPLS QoS uses dedicated bandwidth for enterprise users or
differentiated services (such as voice, video, and data services). MPLS QoS
differentiates data flows based on the EXP field and provides differentiated
services for data flows. The use of MPLS QoS helps minimize delays and ensures
low packet loss ratios for voice and video data streams, guaranteeing high
network usage.
5.2 Understanding MPLS QoS
5.2.1 MPLS DiffServ
Implementation
In the DiffServ model, network edge nodes map a service to a service class based
on QoS requirements. A service class is identified by the differentiated service (DS)
field or Type of Service (ToS) field in IP packets or the PRI field (802.1p priority) in
VLAN packets. Nodes on a backbone network apply preset policies to the service
based on the DS or PRI field to ensure service quality. For details, see Priority
Mapping Configuration in the S1720, S2700, S5700, and S6720 V200R011C10
Configuration Guide - QoS. The service classification and label distribution
mechanisms of DiffServ are similar to MPLS label distribution. MPLS DiffServ
combines DS or PRI distribution with MPLS label distribution.
Figure 5-1 Fields in an MPLS packet
Link layer header
MPLS Label
Layer 3 header
19
0
Label
Layer 3 payload
22 23
Exp S
31
TTL
MPLS DiffServ maps the EXP field (shown in Figure 5-1) to a per-hop behavior
(PHB). LSRs forward MPLS packets based on the EXP field in the MPLS packets.
MPLS DiffServ provides the following solutions for label switched path (LSP) setup:
●
E-LSP
An LSP whose PHB is determined by the EXP field. E-LSP applies to a network
with fewer than eight PHBs. A differentiated services code point (DSCP) or
802.1p priority is mapped to a specified EXP value that identifies a PHB.
Packets are forwarded based on labels, and the EXP field determines the
packet scheduling algorithm and drop priority at each hop. An LSP transmits a
maximum of eight PHB flows that are identified by the EXP field in the MPLS
packet header. The EXP value can be configured by the Internet service
provider (ISP) or mapped from the DSCP or 802.1p priority in a packet. In E-
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LSP, PHB information does not need to be transmitted by signaling protocols.
The label efficiency is high, and its status is easy to maintain.
Table 5-1 describes the mapping between PHBs and EXP values.
Table 5-1 Mapping between DiffServ PHBs and EXP values
●
PHB
EXP Value
BE
0
AF1
1
AF2
2
AF3
3
AF4
4
EF
5
CS6
6
CS7
7
L-LSP
An LSP whose PHB is determined by both the label and EXP value. L-LSP
applies to a network with any number of PHBs. During packet forwarding, the
label of a packet determines the forwarding path and scheduling algorithm.
The EXP field determines the drop priority of the packet. Labels differentiate
service flows, so service flows of different types are transmitted over the same
LSP. This solution requires more labels and occupies a large number of system
resources.
The switch supports only E-LSP.
DiffServ Domain
DiffServ domains include MPLS DiffServ and IP DiffServ domains, as shown in
Figure 5-2.
In the E-LSP solution, MPLS DiffServ manages and schedules packet forwarding
between the MPLS and IP DiffServ domains and implements bidirectional mapping
between DSCP or 802.1p priorities and EXP values at the MPLS network edge.
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Figure 5-2 DiffServ domain
PE
MPLS
DiffServ Domain
PE
CE
CE
IP
DiffServ Domain
IP
DiffServ Domain
Figure 5-3 illustrates how MPLS DiffServ forwards MPLS packets based on EXP
values to provide differentiated services.
Figure 5-3 E-LSP
PE_1
P
EXP=5 EXP=0
PE_2
EXP=0 EXP=5
E-LSP
BE
queue
EF
queue
When MPLS packets enter the P device, the P device classifies packets and maps
EXP values in the packets to CoS values and drop priorities. After traffic
classification, QoS implementations include traffic shaping, traffic policing, and
congestion avoidance are the same as those on an IP network. When MPLS
packets leave the P device, the P device maps CoS values and drop priorities to
EXP values. Therefore the downstream device of the P device provides
differentiated services based on EXP values.
5.2.2 MPLS DiffServ Tunnel Modes
An MPLS VPN DiffServ domain supports three tunnel modes:
●
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Uniform: Packet priorities are uniformly defined on the IP network and the
MPLS network, so the priorities are globally valid. On the ingress node, each
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packet is distributed a label and its DSCP or 802.1p priority is mapped to an
EXP value. A change in the EXP value on the MPLS network determines the
PHB used when the packet leaves the MPLS network. The egress node maps
the EXP value to the DSCP or 802.1p priority. As an example, Figure 5-4
shows priority mapping in uniform mode on an L3VPN network.
Figure 5-4 Priority mapping in uniform mode
CE_1
PE_1
IP DSCP
40
IP/MPLS backbone
network
P_1
P_2
Outer MPLS
EXP 5
Outer MPLS
EXP 6
Inner MPLS
EXP 5
Inner MPLS
EXP 5
Inner MPLS
EXP 6
IP DSCP
40
IP DSCP
40
IP DSCP
40
PE_2
IP DSCP
48
CE_2
IP DSCP
48
P_1 changes the outer MPLS EXP value to 6. P_2 pops out the outer MPLS
label and changes the inner MPLS EXP value to the outer MPLS EXP value.
PE_2 changes the DSCP priority to 48.
●
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Pipe: The EXP value can be manually configured, and the ingress node adds
this EXP value to MPLS packets. Any change in the EXP value is valid only on
the MPLS network. The egress node selects the PHB for MPLS packets
according to the EXP value. When the packets leave the MPLS network, their
DSCP or 802.1p priority is still valid. As an example, Figure 5-5 shows priority
mapping in pipe mode on an L3VPN network.
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Figure 5-5 Priority mapping in pipe mode
CE_1
PE_1
IP DSCP
40
IP/MPLS backbone
network
P_1
P_2
Outer MPLS
EXP 1
Outer MPLS
EXP 1
Inner MPLS
EXP 2
Inner MPLS
EXP 2
Inner MPLS
EXP 1
IP DSCP
40
IP DSCP
40
IP DSCP
40
PE_2
CE_2
Inner MPLS
EXP 1
PHB determined
by the EXP
priority
IP DSCP
40
IP DSCP
40
PE_1 changes the outer and inner MPLS EXP values to 1 and 2. P_2 pops out
the outer MPLS label and changes the inner MPLS EXP value to the outer
MPLS EXP value. PE_2 retains the DSCP priority of packets and selects a PHB
based on the inner MPLS EXP value.
●
Short pipe: The EXP value can be manually configured, and the ingress node
adds this EXP value to MPLS packets. Any change in the EXP value is valid
only on the MPLS network. The egress node selects the PHB for MPLS packets
according to the DSCP or 802.1p priority. When the packets leave the MPLS
network, their DSCP or 802.1p priority is still valid. As an example, Figure 5-6
shows priority mapping in short pipe mode on an L3VPN network.
Figure 5-6 Priority mapping in short pipe mode
CE_1
PE_1
IP DSCP
40
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IP/MPLS backbone
network
P_1
P_2
Outer MPLS
EXP 1
Outer MPLS
EXP 1
Inner MPLS
EXP 2
Inner MPLS
EXP 2
Inner MPLS
EXP 1
IP DSCP
40
IP DSCP
40
IP DSCP
40
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PE_2
CE_2
PHB determined by
the DSCP priority
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PE_1 changes the outer and inner MPLS EXP values to 1 and 2. P_2 pops out
the outer MPLS label and changes the inner MPLS EXP value to the outer
MPLS EXP value. PE_2 retains the DSCP priority of packets and selects a PHB
based on the DSCP priority.
5.3 Application of MPLS QoS in the VPN Service
With the wide application of the MPLS technology, service providers offer VPN
services to enterprises through MPLS networks. VPN is used to connect employees
on a business trip, users in remote branches, and partners to the enterprise
headquarters. However, VPNs need to effectively transmit enterprise operation
data to provide QoS guarantee for enterprise services. For example, bandwidth for
applications such as voice and video services must be ensured so that devices can
preferentially process voice and video flows. The best effort service applies to
services such as World Wide Web (WWW) and email to which timely transmission
and reliability cannot be guaranteed.
MPLS QoS can be deployed to meet these requirements.
Differentiating Priorities of Services in a VPN
When different VPN service flows enter an MPLS network, switches on the MPLS
network must differentiate priorities of those services to provide differentiated
services. In Figure 5-7, two VPN sites are the branches of the same enterprise. The
enterprise network transmits voice, video, and data services, with priorities in a
descending order.
Figure 5-7 Differentiating priorities of services in a VPN
IP/MPLS
backbone network
PE_1
PE_2
P
CE_1
CE_2
VPN Site
Voice
flow
Data
flow
VPN Site
Video
flow
Voice
flow
Data
flow
Video
flow
Packets carry different precedence fields depending on the network type. For
example, packets carry the 802.1p field on a Layer 2 network, the DSCP field on a
Layer 3 network, and the EXP field on an MPLS network. In Figure 5-7, PE_1, P,
and PE_2 process packets as follows:
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●
The ingress node PE_1 maps DSCP priorities carried in IP packets to internal
priorities and colors. It also provides different QoS services according to the
internal priorities and colors. When packets leave PE_1, it re-marks the
internal priorities and colors so that switches on the MPLS network can
provide differentiated services based on the EXP values.
●
The transit node P maps EXP values carried in received packets to internal
priorities and colors and provides different QoS services according to the
internal priorities and colors. When packets leave P, it re-marks EXP values
based on the internal priorities and colors.
●
The egress node PE_2 maps EXP values or DSCP priorities carried in received
packets to internal priorities and colors. It also provides different QoS services
according to the internal priorities and colors. When packets leave PE_2, it remarks DSCP priorities based on the internal priorities and colors, so that
downstream switches can provide differentiated services based on packet
priorities.
Differentiating Priorities of Services for Different VPNs
When service flows enter an MPLS network from different VPNs, switches on the
MPLS network must differentiate priorities to ensure preferential forwarding of
service flows from higher priority enterprises. The switches provide differentiated
services to the service flows based on their priorities.
Figure 5-8 illustrates the differentiating priorities of services for different VPNs.
Figure 5-8 Differentiating priorities of services for different VPNs
Enterprise A
Enterprise A
VPN_1
Site
VPN_1
Site
IP/MPLS
backbone network
CE_1
PE_1
CE_2
CE_3
PE_2
P
VPN_2
Site
CE_4
VPN_2
Site
Enterprise B
Enterprise B
CE_1 and CE_3 belong to VPN_1 and connect to two branches of enterprise A.
CE_2 and CE_4 belong to VPN_2 and connect to two branches of enterprise B.
Packets carry different precedence fields depending on the network type. For
example, packets carry the 802.1p field on a Layer 2 network, the DSCP field on a
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Layer 3 network, and the EXP field on an MPLS network. In Figure 5-8, PE_1, P,
and PE_2 process packets as follows:
●
The ingress node PE_1 maps priorities of packets from enterprises A and B to
EXP values in a descending order. Therefore, switches on the MPLS network
provide differentiated services based on the EXP values.
●
The transit node P maps EXP values carried in received packets to internal
priorities and colors. It also provides different QoS services according to the
internal priorities and colors. When packets leave P, it re-marks EXP values
based on the internal priorities and colors.
●
The egress node PE_2 maps EXP values or DSCP priorities carried in received
packets to internal priorities and colors. It also provides different QoS services
according to the internal priorities and colors. When packets leave PE_2, it remarks DSCP priorities based on the internal priorities and colors, so that
downstream switches can provide differentiated services based on packet
priorities.
5.4 Licensing Requirements and Limitations for MPLS
QoS
Involved Network Elements
Other network elements are not required.
License Requirements
MPLS QoS is a basic feature of a switch and is not under license control.
Version Requirements
Table 5-2 Products and versions supporting MPLS QoS
Produc
t
Product
Model
Software Version
S1700
S1720GFR
Not supported
S1720GW,
S1720GWR
Not supported
S1720GW-E,
S1720GWR-E
Not supported
S1720X,
S1720X-E
Not supported
Other S1700
models
Models that cannot be configured using commands.
For details about features and versions, see S1700
Documentation Bookshelf.
S2700SI
Not supported
S2700
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S3700
S5700
S6700
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Product
Model
Software Version
S2700EI
Not supported
S2710SI
Not supported
S2720EI
Not supported
S2750EI
Not supported
S3700SI,
S3700EI
Not supported
S3700HI
Not supported
S5700LI
Not supported
S5700S-LI
Not supported
S5710-C-LI
Not supported
S5710-X-LI
Not supported
S5700SI
Not supported
S5700EI
Not supported
S5710EI
V200R002C00, V200R003C00, V200R005(C00&C02)
S5720EI
V200R009C00, V200R010C00, V200R011C00,
V200R011C10
S5720LI,
S5720S-LI
Not supported
S5720SI,
S5720S-SI
Not supported
S5700HI
V200R001(C00&C01), V200R002C00, V200R003C00,
V200R005(C00SPC500&C01&C02)
S5710HI
V200R003C00, V200R005(C00&C02&C03)
S5720HI
V200R007C10, V200R009C00, V200R010C00,
V200R011C00, V200R011C10
S5730SI
Not supported
S5730S-EI
Not supported
S6720LI,
S6720S-LI
Not supported
S6720SI,
S6720S-SI
Not supported
S6700EI
V200R005(C00&C01&C02)
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Product
Model
Software Version
S6720EI
V200R008C00, V200R009C00, V200R010C00,
V200R011C00, V200R011C10
S6720S-EI
V200R009C00, V200R010C00, V200R011C00,
V200R011C10
To know details about software mappings, see Hardware Query Tool.
Feature Limitations
On the S5720EI switch, if hardware support for MPLS is displayed as NO in the
output of the display device capability command, the switch does not support
MPLS. In this case, you need to pay attention to the following points:
●
MPLS cannot be enabled on the S5720EI switch. If the switch has been added
to a stack, MPLS cannot be enabled on the stack.
●
The S5720EI switch cannot be added to a stack running MPLS.
5.5 Default Settings for MPLS QoS
By default, the mappings in the DiffServ domain are as follows:
●
Table 5-3 lists the mappings from PHBs and colors to EXP priorities in MPLS
packets.
●
Table 5-4 lists the mappings from EXP priorities in MPLS packets to PHBs and
colors.
Table 5-3 Mappings from PHBs and colors to EXP priorities of outgoing packets in
the DiffServ domain
PHB
Color
EXP Priority
BE
green
0
BE
yellow
0
BE
red
0
AF1
green
1
AF1
yellow
1
AF1
red
1
AF2
green
2
AF2
yellow
2
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PHB
Color
EXP Priority
AF2
red
2
AF3
green
3
AF3
yellow
3
AF3
red
3
AF4
green
4
AF4
yellow
4
AF4
red
4
EF
green
5
EF
yellow
5
EF
red
5
CS6
green
6
CS6
yellow
6
CS6
red
6
CS7
green
7
CS7
yellow
7
CS7
red
7
Table 5-4 Mappings from EXP priorities to PHBs and colors of incoming packets in
the DiffServ domain
EXP Priority
PHB
Color
0
BE
green
1
AF1
green
2
AF2
green
3
AF3
green
4
AF4
green
5
EF
green
6
CS6
green
7
CS7
green
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5.6 Configuring the Mapping of the Precedence in the
Public MPLS Tunnel Label
To implement the QoS function on an MPLS network, the switch needs to
determine the packet precedence according to the tunnel label on the MPLS public
network. Therefore, it is necessary to map the tunnel label to the EXP field.
Pre-configuration Tasks
Before configuring the mapping of the precedence in the tunnel label, complete
the following tasks:
●
Configure a local LDP session. For details, see 4.6 Configuring Basic
Functions of MPLS LDP.
●
Create a DiffServ domain. For details, see Priority Mapping Configuration
(DiffServ Domain Mode) in the S1720, S2700, S5700, and S6720
V200R011C10 Configuration Guide - QoS.
Configuration Procedure
Configure the mapping of the precedence in the tunnel label in the following
sequence.
5.6.1 Creating a DiffServ Domain and Configuring Priority
Mapping
Context
A DiffServ domain comprises of connected DiffServ nodes, which use the same
service policy and implement the same PHBs.
When traffic enters a device, the device maps packet priorities to PHBs and colors.
The device performs congestion management based on PHBs and congestion
avoidance based on colors. When traffic flows out of the device, the device maps
PHBs and colors of packets to priorities. The downstream device provides QoS
services based on packet priorities.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run diffserv domain { default | ds-domain-name }
A DiffServ domain is created and the DiffServ domain view is displayed.
The default domain defines the default mappings from packet priorities to PHBs
and colors. You can modify the mappings defined in the default domain but
cannot delete the default domain.
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Step 3 Define a traffic policy on the device.
●
Run mpls-exp-inbound exp-value phb service-class [ color ]
The inbound interface is configured to map EXP priorities of MPLS packets to
the PHBs and colors.
●
Run mpls-exp-outbound service-class color map exp-value
The outbound interface is configured to map PHBs and colors to EXP priorities
of MPLS packets.
To check the default mappings between PHBs and colors of MPLS packets and EXP
priorities, see mpls-exp-inbound and mpls-exp-outbound commands.
----End
Verifying the Configuration
Run the display diffserv domain [ all | name ds-domain-name ] command to
check the DiffServ domain configuration.
5.6.2 Setting the Priority Mapping for the Public Tunnel
Context
To map priorities of incoming packets to PHBs and colors based on the mappings
defined in a DiffServ domain, bind the DiffServ domain to the inbound interface of
the packets. The system then maps priorities of packets to PHBs and colors based
on the mappings in the DiffServ domain.
To map PHBs and colors of outgoing packets to priorities based on the mappings
defined in a DiffServ domain, bind the DiffServ domain to the outbound interface
of the packets. The system then maps PHBs and colors of outgoing packets to
priorities based on the mappings in the DiffServ domain.
Priority mapping must be configured before the public tunnel is set up. If priority mapping
is configured after the public tunnel is set up, you must restart MPLS LDP; otherwise, the
setting cannot take effect.
Procedure
●
Perform the following steps on the ingress node.
a.
Run system-view
The system view is displayed.
b.
Run mpls-qos ingress { use vpn-label-exp | trust upstream { ds-name |
default | none } }
The PHB/color of packet is mapped to the EXP priority of the public
tunnel on the ingress node.
By default, mapping from the PHB/color to the EXP priority of the public
tunnel is performed according to the settings in the default domain.
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If you want to perform priority mapping based on the EXP priority of the
private tunnel, specify the vpn-label-exp parameter in the command.
●
Perform the following steps on the transit node.
a.
Run system-view
The system view is displayed.
b.
Run mpls-qos transit trust upstream { ds-name | default | none }
Priority mapping is performed based on the EXP priority of the public
tunnel on the transit node.
By default, mapping of the EXP priority of the public tunnel is performed
according to the settings in the default domain.
●
Perform the following steps on the egress node.
a.
Run system-view
The system view is displayed.
b.
Run mpls-qos egress trust upstream { ds-name | default | none }
The EXP priority of the public tunnel is mapped to the PHB/color on the
egress node.
By default, mapping from the EXP priority of the public tunnel to the
PHB/color is performed according to the settings in the default domain.
----End
5.7 Setting the DiffServ Mode Supported by MPLS
VPNs
Pre-configuration Tasks
Before configuring the DiffServ mode supported by MPLS VPNs, configure the
mapping of the precedence in the public MPLS tunnel label. For details, see 5.6
Configuring the Mapping of the Precedence in the Public MPLS Tunnel Label.
Configuration Procedure
You can perform the following configuration tasks in any sequence.
5.7.1 Setting the DiffServ Mode Supported by MPLS L3VPN
Context
To provide QoS guarantee for VPN traffic on an MPLS VPN network, set the
DiffServ mode according to your needs.
●
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If you want to differentiate priorities of different services in a VPN, set the
DiffServ mode to uniform. You can also set the DiffServ mode to pipe or short
pipe, but you need to specify the DiffServ domain in which the mode applies.
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●
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If you want to differentiate priorities of services in different VPNs but not
priorities of services in a VPN, set the DiffServ mode to pipe or short pipe and
specify EXP values in private labels.
If you do not want to change priorities carried in original packets, you are advised
to set the DiffServ mode to pipe or short pipe. In uniform and pipe modes, the
egress node determines the per-hop behavior (PHB) based on the EXP priorities of
packets. In short pipe mode, the egress node determines the PHB based on DSCP
priorities of packets.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run ip vpn-instance vpn-instance-name
The VPN instance view is displayed.
Step 3 Run diffserv-mode { pipe { mpls-exp mpls-exp | domain ds-name } | short-pipe
[ mpls-exp mpls-exp ] domain ds-name | uniform [ domain ds-name ] }
The DiffServ mode supported by the MPLS L3VPN is set.
By default, the DiffServ mode supported by the MPLS L3VPN is uniform.
●
If the mpls-qos ingress trust upstream none or mpls-qos egress trust
upstream none command is configured, the device on the private network
does not perform EXP priority mapping even if you run the diffserv-mode
command.
●
When the DiffServ mode is set to uniform on the ingress node, the ingress
node performs priority mapping in the DiffServ domain specified by the
domain parameter in this command. If the domain parameter is not
specified, the ingress node performs priority mapping in the DiffServ domain
specified by the mpls-qos ingress trust upstream { ds-name | default }
command.
●
In a non-PHP scenario, the egress node performs priority mapping in the
DiffServ domain specified by the mpls-qos egress trust upstream { ds-name
| default } command. In a PHP scenario, the egress node performs priority
mapping in the DiffServ domain specified by the domain parameter in this
command. If the domain parameter is not specified, the egress node performs
priority mapping in the DiffServ domain specified by the mpls-qos egress
trust upstream { ds-name | default } command.
This command must be configured before the instance takes effect; otherwise, you must
reset BGP connections to make the configuration take effect.
----End
5.7.2 Setting the DiffServ Mode Supported by MPLS L2VPN
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Context
To provide QoS guarantee for VPN traffic on an MPLS VPN network, set the
DiffServ mode according to your needs.
●
If you want to differentiate priorities of different services in a VPN, set the
DiffServ mode to uniform. You can also set the DiffServ mode to pipe or short
pipe, but you need to specify the DiffServ domain in which the mode applies.
●
If you want to differentiate priorities of services in different VPNs but not
priorities of services in a VPN, set the DiffServ mode to pipe or short pipe and
specify EXP values in private labels.
If you do not want to change priorities carried in original packets, you are advised
to set the DiffServ mode to pipe or short pipe. In uniform and pipe modes, the
egress node determines the per-hop behavior (PHB) based on the EXP priorities of
packets. In short pipe mode, the egress node determines the PHB based on the
802.1p priorities of packets.
Procedure
●
In VLL networking
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The AC-side interface view is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run diffserv-mode { pipe { mpls-exp mpls-exp | domain ds-name } |
short-pipe [ mpls-exp mpls-exp ] domain ds-name | uniform [ domain
ds-name ] }
The DiffServ mode applied to the VLL network is set.
By default, the DiffServ mode applied to the VLL network is uniform.
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n
If the mpls-qos ingress trust upstream none or mpls-qos egress
trust upstream none command is configured, the device on the
private network does not perform EXP priority mapping even if you
run the diffserv-mode command.
n
When the DiffServ mode is set to uniform on the ingress node, the
ingress node performs priority mapping in the DiffServ domain
specified by the domain parameter in this command. If the domain
parameter is not specified, the ingress node performs priority
mapping in the DiffServ domain specified by the mpls-qos ingress
trust upstream { ds-name | default } command.
n
In a non-PHP scenario, the egress node performs priority mapping in
the DiffServ domain specified by the mpls-qos egress trust
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upstream { ds-name | default } command. In a PHP scenario, the
egress node performs priority mapping in the DiffServ domain
specified by the domain parameter in this command. If the domain
parameter is not specified, the egress node performs priority
mapping in the DiffServ domain specified by the mpls-qos egress
trust upstream { ds-name | default } command.
This command must be run before the VC is set up; otherwise, you must unbind
the bound AC interface and bind the AC interface again to make the command
take effect.
●
In VPLS networking
a.
Run system-view
The system view is displayed.
b.
Run vsi vsi-name
The VSI view is displayed.
c.
Run diffserv-mode { pipe { mpls-exp mpls-exp | domain ds-name } |
short-pipe [ mpls-exp mpls-exp ] domain ds-name | uniform [ domain
ds-name ] }
The DiffServ mode applied to the VPLS network is set.
By default, the DiffServ mode applied to the VPLS network is uniform.
n
If the mpls-qos ingress trust upstream none or mpls-qos egress
trust upstream none command is configured, the device on the
private network does not perform EXP priority mapping even if you
run the diffserv-mode command.
n
When the DiffServ mode is set to uniform on the ingress node, the
ingress node performs priority mapping in the DiffServ domain
specified by the domain parameter in this command. If the domain
parameter is not specified, the ingress node performs priority
mapping in the DiffServ domain specified by the mpls-qos ingress
trust upstream { ds-name | default } command.
n
In a non-PHP scenario, the egress node performs priority mapping in
the DiffServ domain specified by the mpls-qos egress trust
upstream { ds-name | default } command. In a PHP scenario, the
egress node performs priority mapping in the DiffServ domain
specified by the domain parameter in this command. If the domain
parameter is not specified, the egress node performs priority
mapping in the DiffServ domain specified by the mpls-qos egress
trust upstream { ds-name | default } command.
This command must be configured before the instance takes effect; otherwise,
you must enable or disable the VSI to make the configuration take effect.
----End
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5.7.3 Verifying the Configuration of the DiffServ Mode
Supported by MPLS VPNs
Prerequisites
The DiffServ mode supported by the MPLS private network has been configured.
Procedure
●
Run the display mpls l2vc [ vc-id | interface interface-type interface-number
| remote-info [ vc-id | verbose ] | state { down | up } ] command to check
information about the MPLS DiffServ mode used by a VLL.
●
Run the display vsi [ name vsi-name ] [ verbose ] command to check
information about the MPLS DiffServ mode used by a VPLS.
----End
5.8 Configuration Examples for MPLS QoS
5.8.1 Example for Configuring MPLS QoS (L3VPN)
Networking Requirements
Enterprises A and B connect their headquarters to branches by deploying the BGP/
MPLS IP VPN, as shown in Figure 5-9. CE1 and CE3 connect branches to the
headquarters of Enterprise A, and CE2 and CE4 connect branches to the
headquarters of Enterprise B. Enterprise A uses vpna and Enterprise B uses vpnb.
Enterprise A requires a higher service level, so better QoS must be provided for
Enterprise A.
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Figure 5-9 Configuring MPLS QoS
AS: 65410
vpna
AS: 65430
vpna
CE3
CE1
GE0/0/1
VLANIF 10
10.1.1.1/24
GE0/0/1
VLANIF 40
10.3.1.1/24
Loopback1
2.2.2.9/32
GE0/0/1
VLANIF10
10.1.1.2/24
PE1
Loopback1
1.1.1.9/32
GE0/0/1
VLANIF30
172.1.1.2/24
GE0/0/3
VLANIF30
172.1.1.1/24
GE0/0/2
VLANIF20
10.2.1.2/24
GE0/0/2
VLANIF60
172.2.1.1/24
P
AS: 100
GE0/0/1
VLANIF40
10.3.1.2/24
PE2
Loopback1
3.3.3.9/32
GE0/0/3
VLANIF60
172.2.1.2/24
GE0/0/2
VLANIF50
10.4.1.2/24
MPLS backbone
GE0/0/1
VLANIF 50
10.4.1.1/24
GE0/0/1
VLANIF 20
10.2.1.1/24
CE2
CE4
vpnb
vpnb
AS: 65420
AS: 65440
Configuration Roadmap
Configure MPLS QoS on PE1 and PE2. Enable the pipe mode on vpna and vpnb.
Set the MPLS EXP values of vpna and vpnb to 4 and 3 respectively to provide
better QoS guarantee for Enterprise A.
Procedure
Step 1 Configure OSPF on the MPLS backbone network so that PE and P can
communicate with each other.
# Configure PE1.
<HUAWEI> system-view
[HUAWEI] sysname PE1
[PE1] interface loopback 1
[PE1-LoopBack1] ip address 1.1.1.9 32
[PE1-LoopBack1] quit
[PE1] vlan batch 10 20 30
[PE1] interface gigabitethernet 0/0/1
[PE1-GigabitEthernet0/0/1] port link-type trunk
[PE1-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[PE1-GigabitEthernet0/0/1] quit
[PE1] interface gigabitethernet 0/0/2
[PE1-GigabitEthernet0/0/2] port link-type trunk
[PE1-GigabitEthernet0/0/2] port trunk allow-pass vlan 20
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[PE1-GigabitEthernet0/0/2] quit
[PE1] interface gigabitethernet 0/0/3
[PE1-GigabitEthernet0/0/3] port link-type trunk
[PE1-GigabitEthernet0/0/3] port trunk allow-pass vlan 30
[PE1-GigabitEthernet0/0/3] quit
[PE1] interface vlanif 30
[PE1-Vlanif30] ip address 172.1.1.1 24
[PE1-Vlanif30] quit
[PE1] ospf 1
[PE1-ospf-1] area 0
[PE1-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[PE1-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[PE1-ospf-1-area-0.0.0.0] quit
[PE1-ospf-1] quit
# Configure P.
<HUAWEI> system-view
[HUAWEI] sysname P
[P] interface loopback 1
[P-LoopBack1] ip address 2.2.2.9 32
[P-LoopBack1] quit
[P] vlan batch 30 60
[P] interface gigabitethernet 0/0/1
[P-GigabitEthernet0/0/1] port link-type trunk
[P-GigabitEthernet0/0/1] port trunk allow-pass vlan 30
[P-GigabitEthernet0/0/1] quit
[P] interface gigabitethernet 0/0/2
[P-GigabitEthernet0/0/2] port link-type trunk
[P-GigabitEthernet0/0/2] port trunk allow-pass vlan 60
[P-GigabitEthernet0/0/2] quit
[P] interface vlanif 30
[P-Vlanif30] ip address 172.1.1.2 24
[P-Vlanif30] quit
[P] interface vlanif 60
[P-Vlanif60] ip address 172.2.1.1 24
[P-Vlanif60] quit
[P] ospf
[P-ospf-1] area 0
[P-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[P-ospf-1-area-0.0.0.0] network 172.2.1.0 0.0.0.255
[P-ospf-1-area-0.0.0.0] network 2.2.2.9 0.0.0.0
[P-ospf-1-area-0.0.0.0] quit
[P-ospf-1] quit
# Configure PE2.
<HUAWEI> system-view
[HUAWEI] sysname PE2
[PE2] interface loopback 1
[PE2-LoopBack1] ip address 3.3.3.9 32
[PE2-LoopBack1] quit
[PE2] vlan batch 40 50 60
[PE2] interface gigabitethernet 0/0/1
[PE2-GigabitEthernet0/0/1] port link-type trunk
[PE2-GigabitEthernet0/0/1] port trunk allow-pass vlan 40
[PE2-GigabitEthernet0/0/1] quit
[PE2] interface gigabitethernet 0/0/2
[PE2-GigabitEthernet0/0/2] port link-type trunk
[PE2-GigabitEthernet0/0/2] port trunk allow-pass vlan 50
[PE2-GigabitEthernet0/0/2] quit
[PE2] interface gigabitethernet 0/0/3
[PE2-GigabitEthernet0/0/3] port link-type trunk
[PE2-GigabitEthernet0/0/3] port trunk allow-pass vlan 60
[PE2-GigabitEthernet0/0/3] quit
[PE2] interface vlanif 60
[PE2-Vlanif60] ip address 172.2.1.2 24
[PE2-Vlanif60] quit
[PE2] ospf
[PE2-ospf-1] area 0
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[PE2-ospf-1-area-0.0.0.0] network 172.2.1.0 0.0.0.255
[PE2-ospf-1-area-0.0.0.0] network 3.3.3.9 0.0.0.0
[PE2-ospf-1-area-0.0.0.0] quit
[PE2-ospf-1] quit
After the configuration is complete, OSPF neighbor relationships are set up
between PE1, P, and PE2. Run the display ip routing-table command. The
command output shows that PEs have learned the routes to Loopback1 of each
other.
Step 2 Configure basic MPLS functions, enable MPLS LDP, and establish LDP LSPs on the
MPLS backbone network.
# Configure PE1.
[PE1] mpls lsr-id 1.1.1.9
[PE1] mpls
[PE1-mpls] quit
[PE1] mpls ldp
[PE1-mpls-ldp] quit
[PE1] interface vlanif 30
[PE1-Vlanif30] mpls
[PE1-Vlanif30] mpls ldp
[PE1-Vlanif30] quit
# Configure P.
[P] mpls lsr-id 2.2.2.9
[P] mpls
[P-mpls] quit
[P] mpls ldp
[P-mpls-ldp] quit
[P] interface vlanif 30
[P-Vlanif30] mpls
[P-Vlanif30] mpls ldp
[P-Vlanif30] quit
[P] interface vlanif 60
[P-Vlanif60] mpls
[P-Vlanif60] mpls ldp
[P-Vlanif60] quit
# Configure PE2.
[PE2] mpls lsr-id 3.3.3.9
[PE2] mpls
[PE2-mpls] quit
[PE2] mpls ldp
[PE2-mpls-ldp] quit
[PE2] interface vlanif 60
[PE2-Vlanif60] mpls
[PE2-Vlanif60] mpls ldp
[PE2-Vlanif60] quit
After the configuration is complete, LDP sessions are set up between PE1 and P
and between P and PE2. Run the display mpls ldp session command. The
command output shows that the LDP session status is Operational.
PE1 is used as an example
[PE1] display mpls ldp session
LDP Session(s) in Public Network
Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDDD:HH:MM)
A '*' before a session means the session is being deleted.
-----------------------------------------------------------------------------PeerID
Status
LAM SsnRole SsnAge
KASent/Rcv
-----------------------------------------------------------------------------2.2.2.9:0
Operational DU Active 0000:00:01 6/6
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-----------------------------------------------------------------------------TOTAL: 1 session(s) Found.
Step 3 Configure a VPN instance on each PE and connect the CEs to the PEs.
# Configure PE1.
[PE1] ip vpn-instance vpna
[PE1-vpn-instance-vpna] ipv4-family
[PE1-vpn-instance-vpna-af-ipv4] route-distinguisher 100:1
[PE1-vpn-instance-vpna-af-ipv4] vpn-target 111:1 both
[PE1-vpn-instance-vpna-af-ipv4] quit
[PE1-vpn-instance-vpna] quit
[PE1] ip vpn-instance vpnb
[PE1-vpn-instance-vpnb] ipv4-family
[PE1-vpn-instance-vpnb-af-ipv4] route-distinguisher 100:2
[PE1-vpn-instance-vpnb-af-ipv4] vpn-target 222:2 both
[PE1-vpn-instance-vpnb-af-ipv4] quit
[PE1-vpn-instance-vpnb] quit
[PE1] interface vlanif 10
[PE1-Vlanif10] ip binding vpn-instance vpna
[PE1-Vlanif10] ip address 10.1.1.2 24
[PE1-Vlanif10] quit
[PE1] interface vlanif 20
[PE1-Vlanif20] ip binding vpn-instance vpnb
[PE1-Vlanif20] ip address 10.2.1.2 24
[PE1-Vlanif20] quit
# Configure PE2.
[PE2] ip vpn-instance vpna
[PE2-vpn-instance-vpna] ipv4-family
[PE2-vpn-instance-vpna-af-ipv4] route-distinguisher 200:1
[PE2-vpn-instance-vpna-af-ipv4] vpn-target 111:1 both
[PE2-vpn-instance-vpna-af-ipv4] quit
[PE2-vpn-instance-vpna] quit
[PE2] ip vpn-instance vpnb
[PE2-vpn-instance-vpnb] ipv4-family
[PE2-vpn-instance-vpnb-af-ipv4] route-distinguisher 200:2
[PE2-vpn-instance-vpnb-af-ipv4] vpn-target 222:2 both
[PE2-vpn-instance-vpnb-af-ipv4] quit
[PE2-vpn-instance-vpnb] quit
[PE2] interface vlanif 40
[PE2-Vlanif40] ip binding vpn-instance vpna
[PE2-Vlanif40] ip address 10.3.1.2 24
[PE2-Vlanif40] quit
[PE2] interface vlanif 50
[PE2-Vlanif50] ip binding vpn-instance vpnb
[PE2-Vlanif50] ip address 10.4.1.2 24
[PE2-Vlanif50] quit
# Assign IP addresses to the interfaces on the CEs according to Figure 5-9. The
configuration procedure is not mentioned here.
After the configurations are complete, each PE can ping its connected CE.
If a PE has multiple interfaces bound to the same VPN instance, specify a source IP address
by specifying -a source-ip-address in the ping -vpn-instance vpn-instance-name -a sourceip-address dest-ip-address command to ping the CE connected to the remote PE. If you do
not specify a source IP address, the ping fails.
Use the command output on PE1 and CE1 as an example.
[PE1] ping -vpn-instance vpna 10.1.1.1
PING 10.1.1.1: 56 data bytes, press CTRL_C to break
Reply from 10.1.1.1: bytes=56 Sequence=1 ttl=255 time=5 ms
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Reply
Reply
Reply
Reply
from
from
from
from
10.1.1.1:
10.1.1.1:
10.1.1.1:
10.1.1.1:
bytes=56
bytes=56
bytes=56
bytes=56
5 MPLS QoS Configuration
Sequence=2
Sequence=3
Sequence=4
Sequence=5
ttl=255
ttl=255
ttl=255
ttl=255
time=3 ms
time=3 ms
time=3 ms
time=16 ms
--- 10.1.1.1 ping statistics --5 packet(s) transmitted
5 packet(s) received
0.00% packet loss
round-trip min/avg/max = 3/6/16 ms
Step 4 Set up an MP-IBGP peer relationship between PEs.
# Configure PE1.
[PE1] bgp 100
[PE1-bgp] peer 3.3.3.9 as-number 100
[PE1-bgp] peer 3.3.3.9 connect-interface loopback 1
[PE1-bgp] ipv4-family vpnv4
[PE1-bgp-af-vpnv4] peer 3.3.3.9 enable
[PE1-bgp-af-vpnv4] quit
[PE1-bgp] quit
# Configure PE2.
[PE2] bgp 100
[PE2-bgp] peer 1.1.1.9 as-number 100
[PE2-bgp] peer 1.1.1.9 connect-interface loopback 1
[PE2-bgp] ipv4-family vpnv4
[PE2-bgp-af-vpnv4] peer 1.1.1.9 enable
[PE2-bgp-af-vpnv4] quit
[PE2-bgp] quit
After the configuration is complete, run the display bgp peer command on PEs.
The command output shows that the BGP peer relationships have been
established between the PEs.
[PE1] display bgp peer
BGP local router ID : 1.1.1.9
Local AS number : 100
Total number of peers : 1
Peer
V
3.3.3.9
4 100
Peers in established state : 1
AS MsgRcvd MsgSent OutQ Up/Down
12
6
0 00:02:21
State
Established
PrefRcv
0
Step 5 Set up the EBGP peer relationships between the PEs and CEs and import VPN
routes.
# Configure CE1.
[CE1] bgp 65410
[CE1-bgp] peer 10.1.1.2 as-number 100
[CE1-bgp] import-route direct
The configurations of CE2, CE3, and CE4 are similar to the configuration of CE1,
and are not mentioned here.
# Configure PE1.
[PE1] bgp 100
[PE1-bgp] ipv4-family vpn-instance vpna
[PE1-bgp-vpna] peer 10.1.1.1 as-number 65410
[PE1-bgp-vpna] import-route direct
[PE1-bgp-vpna] quit
[PE1-bgp] ipv4-family vpn-instance vpnb
[PE1-bgp-vpnb] peer 10.2.1.1 as-number 65420
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[PE1-bgp-vpnb] import-route direct
[PE1-bgp-vpnb] quit
[PE1-bgp] quit
The configuration of PE2 is similar to that of PE1, and is not mentioned here.
After the configurations are complete, run the display bgp vpnv4 vpn-instance
peer command on the PEs. The command output shows that BGP peer
relationships between PEs and CEs have been established.
Use the peer relationship between PE1 and CE1 as an example.
[PE1] display bgp vpnv4 vpn-instance vpna peer
BGP local router ID : 1.1.1.9
Local AS number : 100
Total number of peers : 1
Peer
V
10.1.1.1
4 65410
Peers in established state : 1
AS MsgRcvd MsgSent OutQ Up/Down
11
9
0 00:07:25
State
Established
PrefRcv
1
Step 6 Configure MPLS QoS.
#Configure PE1.
[PE1] mpls-qos ingress use vpn-label-exp
[PE1] ip vpn-instance vpna
[PE1-vpn-instance-vpna] diffserv-mode pipe mpls-exp 4
[PE1-vpn-instance-vpna] quit
[PE1] ip vpn-instance vpnb
[PE1-vpn-instance-vpnb] diffserv-mode pipe mpls-exp 3
[PE1-vpn-instance-vpnb] quit
#Configure PE2.
[PE2] mpls-qos ingress use vpn-label-exp
[PE2] ip vpn-instance vpna
[PE2-vpn-instance-vpna] diffserv-mode pipe mpls-exp 4
[PE2-vpn-instance-vpna] quit
[PE2] ip vpn-instance vpnb
[PE2-vpn-instance-vpnb] diffserv-mode pipe mpls-exp 3
[PE2-vpn-instance-vpnb] quit
After the configurations are complete, you must reset MPLS LDP and BGP connections to
make the configuration take effect.
----End
Configuration Files
●
PE1 configuration file
#
sysname PE1
#
vlan batch 10 20 30
#
mpls-qos ingress use vpn-label-exp
#
ip vpn-instance vpna
ipv4-family
route-distinguisher 100:1
vpn-target 111:1 export-extcommunity
vpn-target 111:1 import-extcommunity
diffserv-mode pipe mpls-exp 4
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#
ip vpn-instance vpnb
ipv4-family
route-distinguisher 100:2
vpn-target 222:2 export-extcommunity
vpn-target 222:2 import-extcommunity
diffserv-mode pipe mpls-exp 3
#
mpls lsr-id 1.1.1.9
mpls
#
mpls ldp
#
interface Vlanif10
ip binding vpn-instance vpna
ip address 10.1.1.2 255.255.255.0
#
interface Vlanif20
ip binding vpn-instance vpnb
ip address 10.2.1.2 255.255.255.0
#
interface Vlanif30
ip address 172.1.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
bgp 100
peer 3.3.3.9 as-number 100
peer 3.3.3.9 connect-interface LoopBack1
#
ipv4-family unicast
undo synchronization
peer 3.3.3.9 enable
#
ipv4-family vpnv4
policy vpn-target
peer 3.3.3.9 enable
#
ipv4-family vpn-instance vpna
import-route direct
peer 10.1.1.1 as-number 65410
#
ipv4-family vpn-instance vpnb
import-route direct
peer 10.2.1.1 as-number 65420
#
ospf 1
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 172.1.1.0 0.0.0.255
#
return
●
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#
sysname P
#
vlan batch 30 60
#
mpls lsr-id 2.2.2.9
mpls
#
mpls ldp
#
interface Vlanif30
ip address 172.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif60
ip address 172.2.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 60
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.2.1.0 0.0.0.255
#
return
●
PE2 configuration file
#
sysname PE2
#
vlan batch 40 50 60
#
mpls-qos ingress use vpn-label-exp
#
ip vpn-instance vpna
ipv4-family
route-distinguisher 200:1
vpn-target 111:1 export-extcommunity
vpn-target 111:1 import-extcommunity
diffserv-mode pipe mpls-exp 4
#
ip vpn-instance vpnb
ipv4-family
route-distinguisher 200:2
vpn-target 222:2 export-extcommunity
vpn-target 222:2 import-extcommunity
diffserv-mode pipe mpls-exp 3
#
mpls lsr-id 3.3.3.9
mpls
#
mpls ldp
#
interface Vlanif40
ip binding vpn-instance vpna
ip address 10.3.1.2 255.255.255.0
#
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interface Vlanif50
ip binding vpn-instance vpnb
ip address 10.4.1.2 255.255.255.0
#
interface Vlanif60
ip address 172.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 40
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 50
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 60
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
bgp 100
peer 1.1.1.9 as-number 100
peer 1.1.1.9 connect-interface LoopBack1
#
ipv4-family unicast
undo synchronization
peer 1.1.1.9 enable
#
ipv4-family vpnv4
policy vpn-target
peer 1.1.1.9 enable
#
ipv4-family vpn-instance vpna
import-route direct
peer 10.3.1.1 as-number 65430
#
ipv4-family vpn-instance vpnb
import-route direct
peer 10.4.1.1 as-number 65440
#
ospf 1
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 172.2.1.0 0.0.0.255
#
return
●
CE1 configuration file (enterprise A headquarters egress)
#
sysname CE1
#
vlan batch 10
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
bgp 65410
peer 10.1.1.2 as-number 100
#
ipv4-family unicast
undo synchronization
import-route direct
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peer 10.1.1.2 enable
#
return
●
CE2 configuration file (enterprise B headquarters egress)
#
sysname CE2
#
vlan batch 20
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
bgp 65420
peer 10.2.1.2 as-number 100
#
ipv4-family unicast
undo synchronization
import-route direct
peer 10.2.1.2 enable
#
return
●
CE3 configuration file (enterprise A branch egress)
#
sysname CE3
#
vlan batch 40
#
interface Vlanif40
ip address 10.3.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 40
#
bgp 65430
peer 10.3.1.2 as-number 100
#
ipv4-family unicast
undo synchronization
import-route direct
peer 10.3.1.2 enable
#
return
●
CE4 configuration file (enterprise B branch egress)
#
sysname CE4
#
vlan batch 50
#
interface Vlanif50
ip address 10.4.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 50
#
bgp 65440
peer 10.4.1.2 as-number 100
#
ipv4-family unicast
undo synchronization
import-route direct
peer 10.4.1.2 enable
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#
return
5.8.2 Example for Configuring MPLS QoS (L2VPN)
Networking Requirements
In Figure 5-10, CE1 and CE3 are connected to the headquarters and branch of
enterprise A; CE2 and CE4 are connected to the headquarters and branch of
enterprise B. Martini VLL is configured on PE1 and PE2 to enable communication
between the headquarters and branch of the two enterprises separately.
It is required that better QoS guarantee be provided to enterprise A which as a
higher service class.
By default, link type negotiation is enabled globally on the device. If a VLANIF interface is used
as an AC-side interface for L2VPN, the configuration conflicts with link type negotiation. In this
case, run the lnp disable command in the system view to disable link type negotiation.
The lnp disable command has no impact on services before the device restarts. After the device
restarts, the device can only forward packets from the VLANs specified by the port default vlan
command at Layer 2. The port default vlan 1 command is configured by default, so only
packets of VLAN 1 can be forwarded at Layer 2.
Figure 5-10 MPLS QoS networking
Branch of
enterprise A
Headquarters of
enterprise A
GE0/0/1
VLANIF 10
10.1.1.1/24
Loopback1
2.2.2.9/32
GE0/0/1
VLANIF10
PE1
Loopback1
1.1.1.9/32
GE0/0/2
VLANIF20
CE3
CE1
GE0/0/1
VLANIF30
172.1.1.2/24
GE0/0/3
VLANIF30
172.1.1.1/24
GE0/0/2
VLANIF60
172.2.1.1/24
P
GE0/0/1
VLANIF40
PE2
GE0/0/3
VLANIF60
172.2.1.2/24
Loopback1
3.3.3.9/32
GE0/0/2
VLANIF50
GE0/0/1
VLANIF 50
10.2.1.2/24
GE0/0/1
VLANIF 20
10.2.1.1/24
CE2
Headquarters of
enterprise B
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VLANIF 40
10.1.1.2/24
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Branch of
enterprise B
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5 MPLS QoS Configuration
Configuration Roadmap
1.
On the CEs, configure VLANs that interfaces belong to and IP addresses for
VLANIF interfaces.
2.
On PE1, the P, and PE2, configure an IGP routing protocol to implement
interworking among the devices.
3.
On PE1, the P, and PE2, configure basic MPLS functions and MPLS LDP to set
up MPLS LSPs between these devices.
4.
On PE1 and PE2, set up a remote LDP session to exchange VC labels between
them.
5.
On PE1 and PE2, configure MPLS QoS and configure the pipe mode. Set the
MPLS EXP values to 4 and 3 for enterprises A and B, so that better QoS
guarantee can be provided to enterprise A.
6.
On PE1 and PE2, configure Martini VLL.
Procedure
Step 1 On the CEs, configure VLANs that interfaces belong to and IP addresses for
VLANIF interfaces.
# Configure CE1. The configurations of CE2, CE3, and CE4 are similar to the
configuration of CE1, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname CE1
[CE1] vlan batch 10
[CE1] interface vlanif 10
[CE1-Vlanif10] ip address 10.1.1.1 255.255.255.0
[CE1-Vlanif10] quit
[CE1] interface gigabitethernet 0/0/1
[CE1-GigabitEthernet0/0/1] port link-type trunk
[CE1-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[CE1-GigabitEthernet0/0/1] quit
Step 2 Configure OSPF on the MPLS backbone network so that the PEs and P can
communicate with each other.
# Configure PE1.
<HUAWEI> system-view
[HUAWEI] sysname PE1
[PE1] interface loopback 1
[PE1-LoopBack1] ip address 1.1.1.9 32
[PE1-LoopBack1] quit
[PE1] vlan batch 10 20 30
[PE1] interface gigabitethernet 0/0/1
[PE1-GigabitEthernet0/0/1] port link-type trunk
[PE1-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[PE1-GigabitEthernet0/0/1] quit
[PE1] interface gigabitethernet 0/0/2
[PE1-GigabitEthernet0/0/2] port link-type trunk
[PE1-GigabitEthernet0/0/2] port trunk allow-pass vlan 20
[PE1-GigabitEthernet0/0/2] quit
[PE1] interface gigabitethernet 0/0/3
[PE1-GigabitEthernet0/0/3] port link-type trunk
[PE1-GigabitEthernet0/0/3] port trunk allow-pass vlan 30
[PE1-GigabitEthernet0/0/3] quit
[PE1] interface vlanif 30
[PE1-Vlanif30] ip address 172.1.1.1 24
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[PE1-Vlanif30] quit
[PE1] ospf 1
[PE1-ospf-1] area 0
[PE1-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[PE1-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[PE1-ospf-1-area-0.0.0.0] quit
[PE1-ospf-1] quit
# Configure the P.
<HUAWEI> system-view
[HUAWEI] sysname P
[P] interface loopback 1
[P-LoopBack1] ip address 2.2.2.9 32
[P-LoopBack1] quit
[P] vlan batch 30 60
[P] interface gigabitethernet 0/0/1
[P-GigabitEthernet0/0/1] port link-type trunk
[P-GigabitEthernet0/0/1] port trunk allow-pass vlan 30
[P-GigabitEthernet0/0/1] quit
[P] interface gigabitethernet 0/0/2
[P-GigabitEthernet0/0/2] port link-type trunk
[P-GigabitEthernet0/0/2] port trunk allow-pass vlan 60
[P-GigabitEthernet0/0/2] quit
[P] interface vlanif 30
[P-Vlanif30] ip address 172.1.1.2 24
[P-Vlanif30] quit
[P] interface vlanif 60
[P-Vlanif60] ip address 172.2.1.1 24
[P-Vlanif60] quit
[P] ospf
[P-ospf-1] area 0
[P-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[P-ospf-1-area-0.0.0.0] network 172.2.1.0 0.0.0.255
[P-ospf-1-area-0.0.0.0] network 2.2.2.9 0.0.0.0
[P-ospf-1-area-0.0.0.0] quit
[P-ospf-1] quit
# Configure PE2.
<HUAWEI> system-view
[HUAWEI] sysname PE2
[PE2] interface loopback 1
[PE2-LoopBack1] ip address 3.3.3.9 32
[PE2-LoopBack1] quit
[PE2] vlan batch 40 50 60
[PE2] interface gigabitethernet 0/0/1
[PE2-GigabitEthernet0/0/1] port link-type trunk
[PE2-GigabitEthernet0/0/1] port trunk allow-pass vlan 40
[PE2-GigabitEthernet0/0/1] quit
[PE2] interface gigabitethernet 0/0/2
[PE2-GigabitEthernet0/0/2] port link-type trunk
[PE2-GigabitEthernet0/0/2] port trunk allow-pass vlan 50
[PE2-GigabitEthernet0/0/2] quit
[PE2] interface gigabitethernet 0/0/3
[PE2-GigabitEthernet0/0/3] port link-type trunk
[PE2-GigabitEthernet0/0/3] port trunk allow-pass vlan 60
[PE2-GigabitEthernet0/0/3] quit
[PE2] interface vlanif 60
[PE2-Vlanif60] ip address 172.2.1.2 24
[PE2-Vlanif60] quit
[PE2] ospf
[PE2-ospf-1] area 0
[PE2-ospf-1-area-0.0.0.0] network 172.2.1.0 0.0.0.255
[PE2-ospf-1-area-0.0.0.0] network 3.3.3.9 0.0.0.0
[PE2-ospf-1-area-0.0.0.0] quit
[PE2-ospf-1] quit
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After the configuration is complete, OSPF neighbor relationships are set up
between PE1, P, and PE2. Run the display ip routing-table command, and you
can view that the PEs have learned the routes to Loopback1 from each other.
Step 3 Configure basic MPLS functions, enable MPLS LDP, and establish LDP LSPs on the
MPLS backbone network.
# Configure PE1.
[PE1] mpls lsr-id 1.1.1.9
[PE1] mpls
[PE1-mpls] quit
[PE1] mpls ldp
[PE1-mpls-ldp] quit
[PE1] interface vlanif 30
[PE1-Vlanif30] mpls
[PE1-Vlanif30] mpls ldp
[PE1-Vlanif30] quit
# Configure the P.
[P] mpls lsr-id 2.2.2.9
[P] mpls
[P-mpls] quit
[P] mpls ldp
[P-mpls-ldp] quit
[P] interface vlanif 30
[P-Vlanif30] mpls
[P-Vlanif30] mpls ldp
[P-Vlanif30] quit
[P] interface vlanif 60
[P-Vlanif60] mpls
[P-Vlanif60] mpls ldp
[P-Vlanif60] quit
# Configure PE2.
[PE2] mpls lsr-id 3.3.3.9
[PE2] mpls
[PE2-mpls] quit
[PE2] mpls ldp
[PE2-mpls-ldp] quit
[PE2] interface vlanif 60
[PE2-Vlanif60] mpls
[PE2-Vlanif60] mpls ldp
[PE2-Vlanif60] quit
After the configuration is complete, PE1, the P, and PE2 set up LDP sessions. Run
the display mpls ldp session command on PE1, P, and PE2, and you can view that
the LDP session status is Operational. The display on PE1 is used as an example.
[PE1] display mpls ldp session
LDP Session(s) in Public Network
Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDDD:HH:MM)
A '*' before a session means the session is being deleted.
-----------------------------------------------------------------------------PeerID
Status
LAM SsnRole SsnAge
KASent/Rcv
-----------------------------------------------------------------------------2.2.2.9:0
Operational DU Passive 0000:00:01 5/5
-----------------------------------------------------------------------------TOTAL: 1 session(s) Found.
Step 4 Set up remote LDP sessions between the PEs.
# Configure PE1.
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[PE1] mpls ldp remote-peer 3.3.3.9
[PE1-mpls-ldp-remote-3.3.3.9] remote-ip 3.3.3.9
[PE1-mpls-ldp-remote-3.3.3.9] quit
# Configure PE2.
[PE2] mpls ldp remote-peer 1.1.1.9
[PE2-mpls-ldp-remote-1.1.1.9] remote-ip 1.1.1.9
[PE2-mpls-ldp-remote-1.1.1.9] quit
After the configuration is complete, run the display mpls ldp session command
on PE1 to view information about LDP sessions. The command output shows that
two remote LDP sessions to PE2 have been established. The display on PE1 is used
as an example.
[PE1] display mpls ldp session
LDP Session(s) in Public Network
Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDDD:HH:MM)
A '*' before a session means the session is being deleted.
-----------------------------------------------------------------------------PeerID
Status
LAM SsnRole SsnAge
KASent/Rcv
-----------------------------------------------------------------------------2.2.2.9:0
Operational DU Passive 0000:00:09 40/40
3.3.3.9:0
Operational DU Passive 0000:00:09 37/37
-----------------------------------------------------------------------------TOTAL: 2 session(s) Found.
Step 5 Configure MPLS QoS.
# Configure PE1.
[PE1] mpls-qos ingress use vpn-label-exp
[PE1] interface vlanif 10
[PE1-Vlanif10] diffserv-mode pipe mpls-exp 4
[PE1-Vlanif10] quit
[PE1] interface vlanif 20
[PE1-Vlanif20] diffserv-mode pipe mpls-exp 3
[PE1-Vlanif20] quit
# Configure PE2.
[PE2] mpls-qos ingress use vpn-label-exp
[PE2] interface vlanif 40
[PE2-Vlanif40] diffserv-mode pipe mpls-exp 4
[PE2-Vlanif40] quit
[PE2] interface vlanif 50
[PE2-Vlanif50] diffserv-mode pipe mpls-exp 3
[PE2-Vlanif50] quit
After the configuration is complete, run the reset mpls ldp command in the user view to
make the configuration take effect.
Step 6 On the PEs, configure Martini VLL and create VC connections.
# On PE1, create a VC for VLANIF10 connecting to the CE1 interface, and a VC for
VLANIF20 connecting to the CE2 interface. In this example, a VLANIF interface is
used as the AC-side interface, so you need to run the lnp disable command in the
system view before performing the following steps. If you cannot disable link type
negotiation on the live network, do not use a VLANIF interface as the AC-side
interface.
[PE1] mpls l2vpn
[PE1-l2vpn] quit
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[PE1] interface vlanif 10
[PE1-Vlanif10] mpls l2vc 3.3.3.9 101
[PE1-Vlanif10] quit
[PE1] interface vlanif 20
[PE1-Vlanif20] mpls l2vc 3.3.3.9 102
[PE1-Vlanif20] quit
# On PE2, create a VC for VLANIF40 connecting to the CE3 interface, and a VC for
VLANIF50 connecting to the CE4 interface. In this example, a VLANIF interface is
used as the AC-side interface, so you need to run the lnp disable command in the
system view before performing the following steps. If you cannot disable link type
negotiation on the live network, do not use a VLANIF interface as the AC-side
interface.
[PE2] mpls l2vpn
[PE2-l2vpn] quit
[PE2] interface vlanif 40
[PE2-Vlanif40] mpls l2vc 1.1.1.9 101
[PE2-Vlanif40] quit
[PE2] interface vlanif 50
[PE2-Vlanif50] mpls l2vc 1.1.1.9 102
[PE2-Vlanif50] quit
Step 7 Verify the configuration.
# Run the display mpls l2vc command on the PEs. You can view that two L2VCs
in Up state are established and the DiffServ mode is pipe. The display on PE1 is
used as an example.
[PE1] display mpls l2vc
Total LDP VC : 2
2 up
0 down
*client interface
: Vlanif10 is up
Administrator PW
: no
session state
: up
AC status
: up
Ignore AC state
: disable
VC state
: up
Label state
:0
Token state
:0
VC ID
: 101
VC type
: VLAN
destination
: 3.3.3.9
local VC label
: 1031
remote VC label
control word
: disable
remote control word : disable
forwarding entry
: exist
local group ID
:0
remote group ID
:0
local AC OAM State
: up
local PSN OAM State : up
local forwarding state : forwarding
local status code
: 0x0
remote AC OAM state : up
remote PSN OAM state : up
remote forwarding state: forwarding
remote status code
: 0x0
ignore standby state : no
BFD for PW
: unavailable
VCCV State
: up
manual fault
: not set
active state
: active
link state
: up
local VC MTU
: 1500
remote VC MTU
local VCCV
: alert ttl lsp-ping bfd
remote VCCV
: alert ttl lsp-ping bfd
tunnel policy name
: -PW template name
: --
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: 1500
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primary or secondary : primary
load balance type
: flow
Access-port
: false
Switchover Flag
: false
VC tunnel/token info : 1 tunnels/tokens
NO.0 TNL type
: lsp , TNL ID : 0x48000029
Backup TNL type
: lsp , TNL ID : 0x0
create time
: 0 days, 3 hours, 26 minutes, 17 seconds
up time
: 0 days, 0 hours, 26 minutes, 12 seconds
last change time
: 0 days, 0 hours, 26 minutes, 12 seconds
VC last up time
: 2017/10/17 19:02:05
VC total up time
: 0 days, 3 hours, 23 minutes, 8 seconds
CKey
:2
NKey
:1
PW redundancy mode
: frr
AdminPw interface
: -AdminPw link state
: -Diffserv Mode
: pipe
Service Class
: af4
Color
: -DomainId
: -Domain Name
: -*client interface
: Vlanif20 is up
Administrator PW
: no
session state
: up
AC status
: up
Ignore AC state
: disable
VC state
: up
Label state
:0
Token state
:0
VC ID
: 102
VC type
: VLAN
destination
: 3.3.3.9
local VC label
: 1032
remote VC label
: 1031
control word
: disable
remote control word : disable
forwarding entry
: exist
local group ID
:0
remote group ID
:0
local AC OAM State
: up
local PSN OAM State : up
local forwarding state : forwarding
local status code
: 0x0
remote AC OAM state : up
remote PSN OAM state : up
remote forwarding state: forwarding
remote status code
: 0x0
ignore standby state : no
BFD for PW
: unavailable
VCCV State
: up
manual fault
: not set
active state
: active
link state
: up
local VC MTU
: 1500
remote VC MTU
: 1500
local VCCV
: alert ttl lsp-ping bfd
remote VCCV
: alert ttl lsp-ping bfd
tunnel policy name
: -PW template name
: -primary or secondary : primary
load balance type
: flow
Access-port
: false
Switchover Flag
: false
VC tunnel/token info : 1 tunnels/tokens
NO.0 TNL type
: lsp , TNL ID : 0x48000029
Backup TNL type
: lsp , TNL ID : 0x0
create time
: 0 days, 3 hours, 26 minutes, 0 seconds
up time
: 0 days, 0 hours, 26 minutes, 16 seconds
last change time
: 0 days, 0 hours, 26 minutes, 16 seconds
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VC last up time
: 2017/10/17 19:02:05
VC total up time
: 0 days, 3 hours, 22 minutes, 48 seconds
CKey
:3
NKey
:1
PW redundancy mode
: frr
AdminPw interface
: -AdminPw link state
: -Diffserv Mode
: pipe
Service Class
: af3
Color
: -DomainId
: -Domain Name
: --
# CE1 and CE3 can ping each other successfully. CE2 and CE4 can ping each other
successfully. The display on CE1 is used as an example.
[CE1] ping 10.1.1.2
PING 10.1.1.2: 56 data bytes, press CTRL_C to break
Reply from 10.1.1.2: bytes=56 Sequence=1 ttl=254 time=1
Reply from 10.1.1.2: bytes=56 Sequence=2 ttl=254 time=1
Reply from 10.1.1.2: bytes=56 Sequence=3 ttl=254 time=1
Reply from 10.1.1.2: bytes=56 Sequence=4 ttl=254 time=1
Reply from 10.1.1.2: bytes=56 Sequence=5 ttl=254 time=1
ms
ms
ms
ms
ms
--- 10.1.1.2 ping statistics --5 packet(s) transmitted
5 packet(s) received
0.00% packet loss
round-trip min/avg/max = 1/1/1 ms
----End
Configuration Files
●
PE1 configuration file
NOTICE
The lnp disable command has no impact on services before the device
restarts. After the device restarts, the device can only forward packets from
the VLANs specified by the port default vlan command at Layer 2. The port
default vlan 1 command is configured by default, so only packets of VLAN 1
can be forwarded at Layer 2.
#
sysname PE1
#
vlan batch 10 20 30
#
lnp disable
#
mpls lsr-id 1.1.1.9
mpls
#
mpls l2vpn
#
mpls ldp
#
mpls ldp remote-peer 3.3.3.9
remote-ip 3.3.3.9
#
interface Vlanif10
mpls l2vc 3.3.3.9 101
diffserv-mode pipe mpls-exp 4
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#
interface Vlanif20
mpls l2vc 3.3.3.9 102
diffserv-mode pipe mpls-exp 3
#
interface Vlanif30
ip address 172.1.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 30
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 172.1.1.0 0.0.0.255
#
mpls-qos ingress use vpn-label-exp
#
return
●
P configuration file
#
sysname P
#
vlan batch 30 60
#
mpls lsr-id 2.2.2.9
mpls
#
mpls ldp
#
interface Vlanif30
ip address 172.1.1.2 255.255.255.0
mpls
mpls ldp
#
interface Vlanif60
ip address 172.2.1.1 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 60
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 172.1.1.0 0.0.0.255
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network 172.2.1.0 0.0.0.255
#
return
●
PE2 configuration file
NOTICE
The lnp disable command has no impact on services before the device
restarts. After the device restarts, the device can only forward packets from
the VLANs specified by the port default vlan command at Layer 2. The port
default vlan 1 command is configured by default, so only packets of VLAN 1
can be forwarded at Layer 2.
#
sysname PE2
#
vlan batch 40 50 60
#
lnp disable
#
mpls lsr-id 3.3.3.9
mpls
#
mpls l2vpn
#
mpls ldp
#
mpls ldp remote-peer 1.1.1.9
remote-ip 1.1.1.9
#
interface Vlanif40
mpls l2vc 1.1.1.9 101
diffserv-mode pipe mpls-exp 4
#
interface Vlanif50
mpls l2vc 1.1.1.9 102
diffserv-mode pipe mpls-exp 3
#
interface Vlanif60
ip address 172.2.1.2 255.255.255.0
mpls
mpls ldp
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 40
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 50
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 60
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 172.2.1.0 0.0.0.255
#
mpls-qos ingress use vpn-label-exp
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#
return
●
CE1 configuration file
#
sysname CE1
#
vlan batch 10
#
interface Vlanif10
ip address 10.1.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
return
●
CE2 configuration file
#
sysname CE2
#
vlan batch 20
#
interface Vlanif20
ip address 10.2.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 20
#
return
●
CE3 configuration file
#
sysname CE3
#
vlan batch 40
#
interface Vlanif40
ip address 10.1.1.2 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 40
#
return
●
CE4 configuration file
#
sysname CE4
#
vlan batch 50
#
interface Vlanif50
ip address 10.2.1.2 255.255.255.0
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 50
#
return
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6 MPLS TE Configuration
MPLS TE Configuration
About This Chapter
This chapter describes how to configure MPLS TE tunnels that transmit MPLS
L2VPN (VLL and VPLS) services and MPLS L3VPN services and provide high
security and guarantees reliable QoS for VPN services.
6.1 Overview of MPLS TE
6.2 Understanding MPLS TE
6.3 MPLS TE Application on an IP MAN
6.4 Summary of MPLS TE Configuration Tasks
6.5 Licensing Requirements and Limitations for MPLS TE
6.6 Default Settings for MPLS TE
6.7 Configuring a Static MPLS TE Tunnel
6.8 Configuring a Dynamic MPLS TE Tunnel
6.9 Importing Traffic to an MPLS TE Tunnel
6.10 Adjusting RSVP-TE Signaling Parameters
6.11 Adjusting the Path of a CR-LSP
6.12 Adjusting the Establishment of an MPLS TE Tunnel
6.13 Configuring CR-LSP Backup
6.14 Configuring Manual TE FRR
6.15 Configuring Auto TE FRR
6.16 Configuring Association Between TE FRR and CR-LSP Backup
6.17 Configuring a Tunnel Protection Group
6.18 Configuring Dynamic BFD for RSVP
6.19 Configuring Static BFD for CR-LSPs
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6.20 Configuring Dynamic BFD for CR-LSPs
6.21 Configuring Static BFD for TE Tunnels
6.22 Configuring RSVP GR
6.23 Maintaining MPLS TE
6.24 Configuration Examples for MPLS TE
6.1 Overview of MPLS TE
Definition
Multiprotocol Label Switching Traffic Engineering (MPLS TE) establishes
constraint-based routed label switched paths (CR-LSPs) and directs traffic to them.
In this way, network traffic is transmitted over specified paths.
Purpose
On a traditional IP network, nodes select the shortest path as the route to a
destination regardless of other factors such as bandwidth. This routing mechanism
may cause congestion on the shortest path and waste resources on other available
paths, as shown in Figure 6-1.
Figure 6-1 Traditional routing mechanism
Switch_7
Switch_3
80M
Path 1
Switch_4
Switch_2
Path 2
40M
Switch_1
Switch_5
Switch_6
On the network shown in Figure 6-1, each link has a bandwidth of 100 Mbit/s
and the same metric. Switch_1 sends traffic to Switch_4 at 40 Mbit/s, and
Switch_7 sends traffic to Switch_4 at 80 Mbit/s. If the network runs an interior
gateway protocol (IGP) that uses the shortest path mechanism, both the two
shortest paths (Path 1 and Path 2) pass through the link Switch_2->Switch_3>Switch_4. As a result, the link Switch_2->Switch_3->Switch_4 is overloaded,
whereas the link Switch_2->Switch_5->Switch_6->Switch_4 is idle.
Traffic engineering can prevent congestion caused by uneven resource allocation
by allocating some traffic to idle links.
The following TE mechanisms have been available before MPLS TE came into use:
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●
IP TE: This mechanism adjusts path metrics to control traffic transmission
paths. It prevents congestion on some links but may cause congestion on
other links. In addition, path metrics are difficult to adjust on a complex
network because any change on a link affects multiple routes.
●
Asynchronous Transfer Mode (ATM) TE: All IGPs select routes only based on
connections and cannot distribute traffic based on bandwidth and the traffic
attributes of links. The IP over ATM overlay model can overcome this defect
by setting up virtual links to transmit some traffic, which helps ensure proper
traffic distribution and good QoS control. However, ATM TE causes high extra
costs and low scalability on the network.
What is needed is a scalable and simple solution to deploy TE on a large backbone
network. MPLS TE is an ideal solution. As an overlay model, MPLS can set up a
virtual topology over a physical topology and map traffic to the virtual topology.
On the network shown in Figure 6-1, MPLS TE can establish an 80 Mbit/s LSP
over Path 1 and a 40 Mbit/s LSP over Path 2. Traffic is then distributed to the two
LSPs, preventing congestion on a single path.
Figure 6-2 MPLS TE
Switch_7
Switch_3 Path 1
Switch_4
Switch_2
Switch_1
Switch_5 Path 2
Switch_6
Benefits
MPLS TE fully uses network resources and provides bandwidth and QoS guarantee
without the need to upgrade hardware. This significantly reduces network
deployment costs. MPLS TE is easy to deploy and maintain because it is
implemented based on MPLS. In addition, MPLS TE provides various reliability
mechanisms to ensure network and device reliability.
6.2 Understanding MPLS TE
6.2.1 Basic Concepts of MPLS TE
Before starting MPLS TE configuration, you need to understand the following
concepts:
●
LSP
●
MPLS TE Tunnel
●
Link Attributes
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6 MPLS TE Configuration
Tunnel Attributes
LSP
On a label switched path (LSP), traffic forwarding is determined by the labels
added to packets by the ingress node of the LSP. An LSP can be considered as a
tunnel because traffic is transparently transmitted on intermediate nodes along
the LSP.
MPLS TE Tunnel
MPLS TE usually associates multiple LSPs with a virtual tunnel interface to form
an MPLS TE tunnel. An MPLS TE tunnel involves the following terms:
●
Tunnel interface: a point-to-point virtual interface used to encapsulate
packets. Similar to a loopback interface, a tunnel interface is a logical
interface.
●
Tunnel ID: a decimal number that uniquely identifies an MPLS TE tunnel to
facilitate tunnel planning and management.
●
LSP ID: a decimal number that uniquely identifies an LSP to facilitate LSP
planning and management.
Figure 6-3 illustrates the preceding terms. Two LSPs are available on the network.
The path LSRA->LSRB->LSRC->LSRD->LSRE is the primary LSP with an LSP ID of 2.
The path LSRA->LSRF->LSRG->LSRH->LSRE is the backup LSP with an LSP ID of
1024. The two LSPs form an MPLS TE tunnel with a tunnel ID of 100, and the
tunnel interface is Tunnel1.
Figure 6-3 MPLS TE tunnel and LSP
LSRB
Primary LSP
LSRC
LSRD
MPLS TE Tunnel
LSRE
LSRA
LSRF
LSRG
Backup LSP
LSRH
MPLS TE Tunnel:
Tunnel Interface = Tunnel 1
Tunnel ID = 100
Primary LSP ID = 2
Backup LSP ID = 1024
Link Attributes
MPLS TE link attributes identify the bandwidth usage, route cost, and link
reliability on a physical link. The link attributes include:
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Total link bandwidth
Bandwidth of a physical link.
●
Maximum reservable bandwidth
Maximum bandwidth that a link can reserve for an MPLS TE tunnel. The
maximum reservable bandwidth must be lower than or equal to the total link
bandwidth.
●
TE metric
Cost of a TE link. TE metrics are used to control MPLS TE path calculation,
making path calculation more independent of IGP routing. By default, IGP
metrics are used as TE metrics.
●
SRLG
Shared risk link group (SRLG), a group of links that share a physical resource,
such as an optical fiber. Links in an SRLG have the same risk. If one link fails,
other links in the SRLG also fail.
The SRLG attribute is used in CR-LSP hot standby and TE fast reroute (FRR) to
enhance TE tunnel reliability. For details about SRLG, see SRLG.
●
Link administrative group
A 32-bit vector that identifies link attributes, also called a link color. Each bit
can be set to 0 or 1 by the network administrator. A link administrative group
identifies an attribute, such as the link bandwidth or performance. A link
administrative group can also be used for link management. For example, it
can identify that an MPLS TE tunnel passes through a link or that a link is
transmitting multicast services. The administrative group attribute must be
used with the affinity attribute to control path selection.
Tunnel Attributes
An MPLS TE tunnel is composed of several constraint-based routed label switched
paths (CR-LSPs). The constraints for LSP setup are tunnel attributes.
Different from a common LSP (LDP LSP for example), a CR-LSP is set up based on
constraints in addition to routing information, including bandwidth constraints and
path constraints.
●
Bandwidth constraints
Bandwidth constraint is mainly the tunnel bandwidth.
●
Path constraints
Path constraints include explicit path, priority and preemption, route pinning,
affinity attribute, and hop limit.
Constraint-based routing (CR) is a mechanism to create and manage these
constraints, which are described in the following:
●
Tunnel bandwidth
The bandwidth of a tunnel must be planned according to requirements of the
services to be transmitted over the tunnel. The planned bandwidth is reserved
on the links along the tunnel to provide bandwidth guarantee.
●
Explicit path
An explicit path is a CR-LSP manually set up by specifying the nodes to pass
or avoid. Explicit paths are classified into the following types:
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Strict explicit path
On a strict explicit path, all the nodes are manually specified and two
consecutive hops must be directly connected. A strict explicit path
precisely controls the path of an LSP.
Figure 6-4 Strict explicit path
LSRA
Explicit path
LSRB Strict
LSRC Strict
LSRE Strict
LSRD Strict
LSRB
LSRF
LSRD
LSRC
LSRE
Strict explicit path
As shown in Figure 6-4, LSRA is the ingress node, and LSRF is the egress
node. An LSP from LSRA to LSRF is set up over a strict explicit path. LSRB
Strict indicates that this LSP must pass through LSRB, which is directly
connected to LSRA. LSRC Strict indicates that this LSP must pass through
LSRC, which is directly connected to LSRB. The rest may be deduced by
analogy. In this way, the path that the LSP passes through is precisely
controlled.
–
Loose explicit path
A loose explicit path passes through the specified nodes but allows
intermediate nodes between the specified nodes.
Figure 6-5 Loose explicit path
LSRA
LSRB
LSRD
LSRC
LSRE
LSRF
Explicit path
LSRD Loose
Loose explicit path
As shown in Figure 6-5, an LSP is set up over a loose explicit path from
LSRA to LSRF. LSRD Loose indicates that this LSP must pass through
LSRD, but LSRD may not be directly connected to LSRA.
●
Priority and preemption
Priority and preemption determine resources allocated to MPLS TE tunnels
based on the importance of services to be transmitted on the tunnels.
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Setup priorities and holding priorities of tunnels determine whether a new
tunnel can preempt the resources of existing tunnels. If the setup priority of a
new CR-LSP is higher than the holding priority of an existing CR-LSP, the new
CR-LSP can occupy resources of the existing CR-LSP. The priority value ranges
from 0 to 7, among which the value 0 indicates the highest priority, and the
value 7 indicates the lowest priority. The setup priority of a tunnel must be
lower than or equal to the holding priority of the tunnel.
If no path can provide the required bandwidth for a new CR-LSP, an existing
CR-LSP is torn down and its bandwidth is assigned to the new CR-LSP. This is
the preemption process. The following preemption modes are supported:
–
Hard preemption: A high-priority CR-LSP can directly preempt resources
assigned to a low-priority CR-LSP. As a result, some traffic is dropped on
the low-priority CR-LSP.
–
Soft preemption: The make-before-break mechanism applies to resource
preemption. A high-priority CR-LSP preempts bandwidth assigned to a
lower-priority CR-LSP only after traffic over the low-priority CR-LSP
switches to a new CR-LSP.
The priority and preemption attributes determine resource preemption among
tunnels. If multiple CR-LSPs need to be set up, CR-LSPs with higher setup
priorities can be set up by preempting resources. If resources (such as
bandwidth) are insufficient, a CR-LSP with a higher setup priority can preempt
resources of an established CR-LSP with a lower holding priority.
As shown in Figure 6-6, links on the network have different bandwidth values
but the same metric value. There are two TE tunnels on the network:
–
Tunnel 1: established over Path 1. Its bandwidth is 100 Mbit/s, and its
setup and holding priority values are 0.
–
Tunnel 2: established over Path 2. Its bandwidth is 100 Mbit/s, and its
setup and holding priority values are 7.
Figure 6-6 Before a link failure occurs
LSRF
LSRA
Tunnel 1
1G
Path1
100M
LSRB
1G
100M
Tunnel 2
1G
Path2
100M
LSRC
100M
LSRD
LSRE
Path of Tunnel 1
Path of Tunnel 2
When the link between LSRB and LSRE fails, LSRA calculates a new path, Path
3 (LSRA->LSRB->LSRF->LSRE), for Tunnel 1. The bandwidth of the link
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between LSRB and LSRF is insufficient for tunnels Tunnel 1 and Tunnel 2. As a
result, preemption is triggered, as shown in Figure 6-7.
Figure 6-7 After preemption is triggered
LSRF
LSRA
Tunnel 1
1G
Path3
Preemption
occurs
LSRB
100M
100M
Tunnel 2
1G
Path2
100M
LSRC
1G
Path4
100M
LSRD
LSRE
New path of Tunnel 1
Old path of Tunnel 2
New path of Tunnel 2
Link failure
A new path is set up for Tunnel 1 as follows:
●
a.
After MPLS TE path calculation is complete, Path messages are
transmitted along the path LSRA->LSRB->LSRF->LSRE, and Resv
messages are transmitted along the path LSRE->LSRF->LSRB->LSRA.
b.
When a Resv message is sent from LSRF to LSRB, LSRB needs to reserve
bandwidth for the new path but finds that bandwidth is insufficient. Then
preemption occurs. LSRB processes the low-priority path differently in
hard and soft preemption modes:
n
In hard preemption mode: Tunnel 1 has a higher priority than Tunnel
2, so LSRB tears down Path 2 of Tunnel 2. In addition, LSRB sends a
PathTear message to request LSRF to delete the path information,
and sends a ResvTear to request LSRC to delete the reservation state.
If traffic is being transmitted on Tunnel 2, some traffic is dropped.
n
In soft preemption mode: LSRB sends a ResvTear message to LSRC. A
new path, Path 4, is set up while Path 2 is not torn down. After
traffic on Path 2 is switched to Path 4, LSRB and LSRC tear down
Path 2 on Tunnel 2.
Path locking
Changes in the network topology or some tunnel attributes may require a CRLSP to be reestablished. Reestablishing a CR-LSP may cause the following
problems:
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The new CR-LSP is set up along a different path than the original one,
making network maintenance inconvenient.
–
Some traffic is dropped when traffic is switched from the original CR-LSP
to the new one.
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Path locking can prevent a CR-LSP from changing its path when routes
change. This feature ensures continuity of service traffic and improves service
reliability.
●
Affinity attribute
The affinity attribute is a 32-bit vector that specifies the links required for a
TE tunnel. This attribute is configured on the ingress node of a tunnel and
must be used with the link administrative group attribute.
After the affinity attribute is configured for a tunnel, a label switching router
(LSR) compares the affinity attribute with the administrative group attribute
of a link to determine whether to select or avoid the link during MPLS TE
path calculation. A 32-bit mask identifies the bits to be compared in the
affinity and administrative group attributes. An LSR performs an AND
operation on the affinity and administrative group attributes with the mask
and compares the results of the AND operations. If the two results are the
same, the LSR selects the link. If the two results are different, the LSR avoids
the link. The rules for comparing the affinity and administrative group
attributes are as follows:
–
Among the bits mapping the 1 bits in the mask, at least one
administrative group bit and the corresponding affinity bit must be 1. The
administrative group bits corresponding to the 0 bits in the affinity
attribute must also be 0.
For example, if the affinity attribute is 0x0000FFFF of a tunnel and the
mask is 0xFFFFFFFF, the administrative group attribute of an available
link must have all 0s in its leftmost 16 bits and at least one 1 bit in its
rightmost 16 bits. Therefore, links with the administrative group values in
the range of 0x00000001 to 0x0000FFFF can be selected for the tunnel.
–
An LSR does not check the administrative group bits mapping 0 bits in
the mask.
For example, if the affinity attribute of a tunnel is 0xFFFFFFFF and the
mask is 0xFFFF0000, the administrative group attribute of an available
link must have at least one 1 bit in its leftmost 16 bits. The rightmost 16
bits of the administrative group attribute can be 0 or 1. Therefore, links
with the administrative group values in the range of 0x00010000 to
0xFFFFFFFF can be selected for the tunnel.
Devices from different vendors may follow different rules to compare the
administrative group and affinity attributes. When using devices from different
vendors on your network, understand their implementations and ensure that they can
interoperate with one another.
A network administrator can use the administrative group and affinity
attributes to control path selection for tunnels.
●
Hop limit
Hop limit is a condition for path selection during CR-LSP setup. Similar to the
administrative group and affinity attributes, hop limit controls the number of
hops allowed on a CR-LSP.
6.2.2 Implementation
Figure 6-8 illustrates the MPLS TE framework.
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Figure 6-8 MPLS TE framework
Upstream
nodes
Path
establishment
Information
advertisement
Downstream
nodes
Local nodes
IGP route
selection
LSP route
selection
LSDB
TEDB
Signaling
protocol
Information
advertisement
IS-IS/OSPF routing
Incoming
packets
Path
establishment
Outgoing
packets
Traffic forwarding
Protocol packet exchanging
Data packet forwarding
Internal information
processsing
MPLS TE is implemented based on four functions:
●
IGP-based information advertisement for TE information collection
●
Path calculation using the collected information
●
Path setup through signaling packet exchange between upstream and
downstream nodes
●
Traffic forwarding over an established MPLS TE tunnel
Table 6-1 describes the four functions.
Table 6-1 Functions for MPLS TE implementation
N
o.
Function
Description
1
Informati
on
advertise
ment
Collects network load information in addition to routing
information. MPLS TE extends an IGP to advertise TE
information, including the maximum link bandwidth,
maximum reservable bandwidth, reserved bandwidth, and link
colors.
Every node collects TE information about all links in a local
area and generates a traffic engineering database (TEDB).
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N
o.
Function
Description
2
Path
calculatio
n
Uses the Constrained Shortest Path First (CSPF) algorithm and
data in the TEDB to calculate a path that satisfies specific
constraints. CSPF evolves from the Shortest Path First (SPF)
algorithm. It excludes nodes and links that do not satisfy
specific constraints and uses the SPF algorithm to calculate a
path.
3
Path
setup
Sets up a static or dynamic CR-LSP.
● Static CR-LSP
Forwarding and resource information is manually
configured for a CR-LSP without the need of a signaling
protocol or path calculation. Setting up a static CR-LSP
consumes few resources because no MPLS control packets
are exchanged between the two ends of the CR-LSP. Static
CR-LSPs cannot be adjusted dynamically; therefore, static
CR-LSP setup applies only to small networks with simple
topologies.
● Dynamic CR-LSP
Nodes on a network use the Resource Reservation Protocol
(RSVP) TE signaling protocol to set up CR-LSP tunnels.
RSVP-TE messages carry constraints for a CR-LSP, such as
the bandwidth, explicit path, and affinity attribute.
There is no need to manually configure each hop along a
dynamic CR-LSP. Dynamic CR-LSP setup applies to largescale networks.
RSVP authentication can be used to enhance security and
reliability of CR-LSPs.
4
Traffic
forwardin
g
Directs traffic to an MPLS TE tunnel and forwards traffic over
the MPLS TE tunnel. The first three functions set up an MPLS
TE tunnel, and the traffic forwarding function directs traffic
arriving at a node to the MPLS-TE tunnel.
● A static CR-LSP is manually established and does not require information advertisement
or path calculation.
● A dynamic CR-LSP is set up using a signaling protocol and involves all the four functions
listed in the table.
To deploy MPLS TE on a network, you must configure link and tunnel attributes.
Then MPLS TE sets up tunnels automatically. After a tunnel is set up, traffic is
directed to the tunnel for forwarding.
6.2.3 Information Advertisement
MPLS TE uses a routing protocol to advertise information about resources
allocated to network nodes. Each node on an MPLS TE network, especially the
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ingress node, determines the path of a tunnel according to the advertised
information.
What Information Is Advertised
The following information is advertised on an MPLS TE network:
●
Link information: includes interface IP addresses, link types, and link metrics,
which are collected by an IGP.
●
Bandwidth information: includes the maximum link bandwidth, maximum
reservable bandwidth, and available bandwidth corresponding to each link
priority.
●
TE metric: indicates the metric value of a link. By default, IGP metric is used
as TE metric.
●
Link administrative group: indicates the color of a link.
●
Affinity attribute: indicates the link colors required for a TE tunnel.
●
Shared risk link group (SRLG): is a constraint for path calculation, which
prevents the backup path of a tunnel from being set up on links with the
same risk level as the primary path.
How Information Is Advertised
TE information is advertised using extensions of link-state routing protocols: OSPF
TE and IS-IS TE. The Open Shortest Path First (OSPF) and Intermediate System to
Intermediate System (IS-IS) protocols collect TE information on a node and flood
the collected information to other nodes on the MPLS TE network.
OSPF TE
OSPF is a link state routing protocol that supports flexible extensions. It defines
link-state advertisements (LSAs) of Type-1 to Type-5 and Type-7 to carry interarea, intra-area, and autonomous system (AS) external routing information.
Formats of these LSAs do not meet the requirements of MPLS TE; therefore, two
extended LSAs, Opaque LSA and TE LSA, are defined to implement MPLS TE.
●
Opaque LSA
Opaque LSAs include Type-9, Type-10, and Type-11 LSAs. Type-9 LSAs can
only be flooded to the local network connected to an interface, and Type-10
LSAs can only be flooded to the local area. Type-11 LSAs are similar to Type-5
LSAs and can be flooded to the local AS except stub areas and not-so-stubby
areas (NSSAs).
An Opaque LSA has the same header format as the other types of LSAs,
except that the four-byte Link State ID field is divided into an Opaque Type
field and an Opaque ID field, as shown in Figure 6-9.
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Figure 6-9 Opaque LSA format
The Opaque Type field is the leftmost byte that identifies the application type
of an Opaque LSA. The Opaque ID field is the rightmost three bytes that
differentiate LSAs of the same type. Therefore, each type of Opaque LSA has
255 applications, and each application has 16777216 different LSAs within a
flooding scope.
For example, OSPF Graceful Restart LSAs are Type-9 LSAs with the Opaque
Type of 3, and TE LSAs are Type-10 LSAs with the Opaque Type of 1.
The Opaque Information field contains the content to be advertised by an
LSA. The information format is defined by the specific application. The
commonly used format is the extensible Type/Length/Value (TLV) structure.
Figure 6-10 TLV structure
●
–
Type: indicates the type of information carried in the TLV.
–
Length: indicates the number of bytes in the Value field.
–
Value: indicates information carried in the TLV. This field can be another
TLV (sub-TLV).
TE LSA
TE LSAs are Type-10 LSAs applied to TE. The Opaque Type of TE LSAs is 1.
Therefore, TE LSAs have a link state ID of 1.x.x.x and are flooded within an
area. Figure 6-11 shows the TE LSA structure.
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Figure 6-11 TE LSA structure
TE LSAs carry information in TLVs. Two types of TLVs are defined for TE LSAs:
–
TLV Type 1
It is a Router Address TLV that uniquely identifies an MPLS node. A
Router Address TLV plays the same role as a router ID in the Constrained
Shortest Path First (CSPF) algorithm.
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TLV Type 2
It is a Link TLV that carries attributes of an MPLS TE capable link. Table
6-2 lists the sub-TLVs that can be carried in a Link TLV.
Table 6-2 Sub-TLVs in a Link TLV
Sub-TLV
Description
Type 1: Link Type (with a 1-byte
Value field)
Carries a link type.
● 1: point-to-point link
● 2: multi-access link
The Value field of this sub-TLV is
followed by a 3-byte padding field.
Type 2: Link ID (with a 4-byte
Value field)
Carries a link identifier in IP address
format.
● For a point-to-point link, this sub-TLV
indicates the OSPF router ID of a
neighbor.
● For a multi-access link, this sub-TLV
indicates the interface IP address of
the designated router (DR).
Type 3: Local IP Address (with a
4N-byte Value field)
Carries one or more local interface IP
addresses. Each IP address occupies 4
bytes.
Type 4: Remote IP Address (with
a 4N-byte Value field)
Carries one or more remote interface IP
addresses. Each IP address occupies 4
bytes.
● For a point-to-point link, this sub-TLV
is filled with a remote IP address.
● For a multi-access link, this sub-TLV is
filled with 0.0.0.0 or is not carried in
the TLV.
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Type 5: Traffic Engineering
Metric (with a 4-byte Value
field)
Carries the TE metric configured on a TE
link. The data format is ULONG.
Type 6: Maximum Bandwidth
(with a 4-byte Value field)
Carries the maximum bandwidth of a
link. The value is a 4-byte floating point
number.
Type 7: Maximum Reservable
Bandwidth (with a 4-byte Value
field)
Carries the maximum reservable
bandwidth of a link. The value is a 4byte floating point number.
Type 8: Unreserved Bandwidth
(with a 32-byte Value field)
Carries reservable bandwidth values for
the eight priorities of a link. The
bandwidth for each priority is a 4-byte
floating point number.
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Sub-TLV
Description
Type 9: Administrative Group
(with a 4-byte Value field)
Carries the administrative group
attribute of a link.
If an OSPF-capable link that has established an OSPF neighbor relationship is
identified as an MPLS TE link, OSPF TE generates a TE LSA carrying
information about the MPLS TE link and advertises the TE LSA to the local
area. If other nodes in the local area support TE extensions, these nodes
establish a topology of TE links. Each node that advertises TE LSAs must have
a unique router address.
Type-10 Opaque LSAs are advertised within an OSPF, so CSPF calculation is
performed on an area basis. To calculate an LSP spanning multiple areas,
CSPF calculation must be performed in each area.
IS-IS TE
IS-IS is a link state routing protocol and supports TE extensions to advertise TE
information.
IS-IS TE defines two new TLV types:
●
Type 135: Wide Metric
IS-IS has two metrics:
–
Narrow metric: 6 bits
–
Wide metric: 32 bits. Wide Metric TLVs are only used to transmit TE
information and cannot be used for route calculation.
A Narrow Metric TLV supports only 64 vector values and cannot meet traffic
engineering requirements on large-scale networks. Wide Metric TLVs are more
suitable for TE information advertisement.
To allow for the transition from Narrow Metric to Wide Metric, IS-IS TE
defines the following vector values:
●
–
Compatible: allows a device to send and receive packets with narrow and
wide metrics.
–
Wide Compatible: allows a device to receive packets with narrow and
wide metrics but to send only packets with wide metrics.
Type 22: IS Reachability TLV
Figure 6-12 shows the format of an IS Reachability TLV.
Figure 6-12 IS Reachability TLV format
0
15
23
System ID and pseudonode number ( 7 octets )
Link metric ( continued )
31
Link metric
( 3 octets )
sub-TLV length ( 1 octets )
sub-TLVs ( 0~244 octets)
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An IS Reachability TLV consists of the following:
–
System ID and pseudo node ID
–
Default link metric
–
Length of sub-TLVs
–
Variable-length sub-TLVs
Table 6-3 describes sub-TLVs in an IS Reachability TLV.
Table 6-3 Sub-TLVs in an IS Reachability TLV
Sub-TLV
Description
Type 3: Administrative group (with a 4byte Value field)
Indicates the administrative
attribute of a link. The 32 bits
in the attribute represent 32
administrative groups.
Type 6: IPv4 interface address (with a 4Nbyte Value field)
Carries one or more local
interface IP addresses. Each IP
address occupies 4 bytes.
Type 8: IPv4 neighbor address (with a 4Nbyte Value field)
Indicates one or more remote
interface IP addresses. Each IP
address occupies 4 bytes.
● For a point-to-point link,
this sub-TLV is filled with a
remote IP address.
● For a multi-access link, this
sub-TLV is filled with
0.0.0.0.
Type 9: Maximum link bandwidth (with a
4-byte Value field)
Carries the maximum
bandwidth of a link.
Type 10: Reservable link bandwidth (with a
4-byte Value field)
Carries the maximum
reservable bandwidth of a
link.
Type 11: Unreserved bandwidth (with a
32-byte Value field)
Carries reservable bandwidth
for eight priorities of a link.
Type 18: TE Default metric (with a 3-byte
Value field)
Carries the TE metric
configured on a TE link.
When Information Is Advertised
To maintain a uniform traffic engineering database (TEDB) in an area, OSPF TE
and IS-IS TE must flood the area with link information. Besides configuration of a
new MPLS TE tunnel, the following conditions can trigger TE information flooding:
●
The IGP TE flooding interval expires. (The flooding interval is configurable.)
●
A link is activated or fails.
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●
An LSP cannot be set up because of insufficient bandwidth. In this case, the
local node immediately floods the current available link bandwidth in the
area.
●
Link attributes, such as the administrative group and affinity attributes,
change.
●
The link bandwidth changes.
When the available bandwidth of an MPLS interface changes, the local node
updates TEDB and floods the updated link information. If a node needs to
reserve bandwidth for a large number of tunnels to be set up, the system
frequently updates the TEDB and triggers flooding. For example, if 100
tunnels with 1 Mbit/s bandwidth need to be set up on a 100 Mbit/s link, the
system needs to flood link information 100 times.
MPLS TE uses a bandwidth flooding mechanism to reduce the frequency of
TEDB updating and flooding. When either of the following conditions is met,
an IGP floods link information and updates the TEDB:
–
The ratio between bandwidth reserved for an MPLS TE tunnel on a link
and available link bandwidth in the TEDB is larger than or equal to the
configured threshold.
–
The ratio between bandwidth released from an MPLS TE tunnel and
available link bandwidth in the TEDB is larger than or equal to the
configured threshold.
Assume that available bandwidth of a link is 100 Mbit/s. If 100 MPLS TE
tunnels with 1 Mbit/s bandwidth need to be set up on the link and the
flooding threshold is 10%, the ratios between reserved bandwidth and
available bandwidth and the flooding process are shown in Figure 6-13.
The system does not flood bandwidth information when creating tunnels 1 to
9. When tunnel 10 is created, the system floods the 10 Mbit/s bandwidth
occupied by the 10 tunnels. The available bandwidth is now 90 Mbit/s.
Similarly, the system does not flood bandwidth information when creating
tunnels 11 to 18, and it does not flood bandwidth information until tunnel 19
is created. The other flooding processes can be deducted by analogy.
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Figure 6-13 Ratios between reserved bandwidth and available bandwidth
10%
9%
10%
8.9%
7.8%
6.7%
8%
7%
6%
5.6%
5%
4.4%
4%
2.2%
1.1%
2%
1%
1 2
3
4 5
3.8%
3.3%
3%
6
7
2.5%
1.3%
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22......
First flooding
Original available
bandwidth 100Mbit/s Available bandiwdth
90Mbit/s
Second flooding
Available bandwidth
81Mbit/s
Information Advertisement Result
After an OSPF TE or IS-IS TE flooding process is complete, all nodes in the local
area generate the same TEDB.
Nodes on an MPLS TE network need to advertise resource information. Each
device collects link information in the local area, such as constraints and
bandwidth usage, and generates a database of link attributes and topology
attributes. This database is the TEDB.
A device calculates the optimal path to another node in the local area according
to information in the TEDB. MPLS TE then uses this path to set up a CR-LSP.
The TEDB is independent of the link state database (LSDB) of an IGP. Both the
two databases are generated through IGP-based flooding, but they record
different information and provide different functions. The TEDB stores TE
information in addition to all information available in the LSDB. The LSDB is used
to calculate the shortest path, whereas the TEDB is used to calculate the best LSP
for an MPLS TE tunnel.
6.2.4 Path Calculation
MPLS TE uses the Constrained Shortest Path First (CSPF) algorithm to calculate
the optimal path to a node. CSPF was developed based on shortest path first
(SPF).
Elements for CSPF Calculation
CSPF calculation depends on the following factors:
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●
Constraints for LSP setup, including the LSP bandwidth, explicit path, setup/
holding priority, and affinity attribute, all of which are configured on the
ingress node
●
Traffic engineering database (TEDB)
A TEDB can be generated only when OSPF TE or IS-IS TE is configured. On an IGP TEincapable network, CR-LSPs are established based on IGP routes, but not calculated using
CSPF.
CSPF Calculation Process
To find the shortest path to the destination, CSPF excludes the links whose
attributes do not meet LSP setup constraints in the TEDB and then calculates the
metrics of other paths using the SPF algorithm.
If both OSPF TE and IS-IS TE are deployed, CSPF uses the OSPF TEDB to calculate a CR-LSP.
If a CR-LSP is calculated using the OSPF TEDB, CSPF does not use the IS-IS TEDB. If no CRLSP is calculated using the OSPF TEDB, CSPF uses the IS-IS TEDB to calculate a CR-LSP.
Whether OSPF TEDB or IS-IS TEDB is used first in the CSPF calculation is determined by the
administrator.
If there are multiple shortest paths with the same metric, CSPF uses a tie-breaking
policy to select one of them. The following tie-breaking policies are available:
●
Most-fill: selects the link with the highest proportion of used bandwidth to
the maximum reservable bandwidth. This policy uses the full bandwidth of a
link.
●
Least-fill: selects the link with the lowest proportion of used bandwidth to the
maximum reservable bandwidth. This policy uses consistent bandwidth
resources on links.
●
Random: selects a random path among equal-metric paths. This policy sets
LSPs consistently over links, regardless of bandwidth distribution.
When several links have the same proportion of used bandwidth to the maximum
reservable bandwidth, CSPF selects the link discovered first, irrespective of mostfill or least-fill.
Figure 6-14 shows an example of CSPF calculation. Figure 6-14 shows the color
and bandwidth of some links. The other links are black and have a bandwidth of
100 Mbit/s. A path to LSRE needs to be set up on the network and must pass
through LSRH, with a bandwidth of 80 Mbit/s and an affinity attribute of black.
According to the constraints, CSPF excludes the blue links, 50 Mbit/s links, and
links not connected to LSRH.
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Figure 6-14 Excluding links
LSRB
LSRC
LSRD
50
LSRA
Bl
ue
ue
ue
Bl
Bl
50
LSRF
LSRE
LSRG
50
LSRH
MPLS TE Tunnel 1:
Destination = LSRE
Bandwidth = 80Mbit/s
Affinity Property = Black
LSRH Loose
LSRC
LSRD
Calculated topology
LSRA
LSRE
LSRF
LSRG
LSRH
After excluding unqualified links, CSPF uses the SPF algorithm to calculate the
path. Figure 6-15 shows the calculation result.
Figure 6-15 CSPF calculation result
LSRD
LSRE
LSRA
LSRF
LSRG
LSRH
Differences Between CSPF and SPF
CSPF is specific to MPLS TE path calculation and differs from SPF in the following
aspects:
●
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CSPF only calculates the shortest path from an ingress node to an egress
node, while SPF calculates the shortest path from a node to all the other
nodes on a network.
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●
CSPF uses path constraints such as link bandwidth, link attributes, and affinity
attributes as metrics, while SPF simply uses link costs as metrics.
●
CSPF does not support load balancing and uses tie-breaking policies to
determine a path if multiple paths have the same metric.
6.2.5 CS-LSP Setup
6.2.5.1 Overview of CR-LSP Setup
CR-LSP Setup Modes
A CR-LSP can be statically or dynamically set up.
A static CR-LSP is set up depending on manual configuration. This section
describes how dynamic CR-LSPs are set up through RSVP-TE.
Overview of RSVP-TE
The Resource Reservation Protocol (RSVP) is designed for the integrated services
model, and reserves resources for nodes along a path. This bandwidth reservation
capability makes RSVP-TE a suitable signaling protocol for establishing MPLS TE
paths.
RSVP-TE provides the following extensions based on RSVP to support MPLS TE
implementation:
●
RSVP-TE adds Label Request objects to Path messages to request labels and
adds Label objects to Resv messages to allocate labels.
●
An extended RSVP message can carry path constraints in addition to label
binding information.
●
The extended objects carry MPLS TE bandwidth constraints to implement
resource reservation.
RSVP Message Types
RSVP defines the following types of messages:
●
Path message: is sent downstream by the sender and saves path information
on the nodes it passes through.
●
Resv message: is sent upstream by the receiver to respond to the Path
message and to request resource reservation.
●
PathErr message: is sent by an RSVP node to its upstream node if an error
occurs while this node is processing a Path message.
●
ResvErr message: is sent by an RSVP node to its downstream node if an error
occurs while this node is processing a Resv message.
●
PathTear message: is sent to delete path information and functions in the
opposite way to a Path message.
●
ResvTear message: is sent to delete the resource reservation state and
functions in the opposite way to a Resv message.
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●
ResvConf message: is sent downstream from the sender hop by hop to
confirm a resource reservation request. This message is sent only when the
Resv message contains the RESV_CONFIRM object.
●
Srefresh message: is used to update the RSVP state.
RSVP-TE Implementation
Table 6-4 describes RSVP-TE implementation.
Table 6-4 RSVP-TE implementation
Function
Description
6.2.5.2 Setup of
Dynamic CR-LSPs
A CR-LSP is set up according to the CSPF calculation result
or an explicit path. CR-LSP setup is triggered on the
ingress node.
6.2.5.3
Maintenance of
Dynamic CR-LSPs
● Path Status Maintenance
After a CR-LSP is set up, RSVP-TE still sends RSVP
messages to maintain the path state on each node.
● Error Signaling
RSVP nodes send error messages to notify upstream
and downstream nodes that faults have occurred
during path establishment or maintenance.
● Path Teardown
A CR-LSP is torn down, and labels and bandwidth on
each node are released. The ingress node initiates
teardown requests.
6.2.5.2 Setup of Dynamic CR-LSPs
To establish a dynamic CR-LSP from an ingress node to an egress node, the ingress
node sends Path messages to the egress node and the egress node sends Resv
messages back to the ingress node. Path messages are sent to create Resource
Reservation Protocol (RSVP) sessions and associate the path status. Every node
that receives a path message creates a path state block (PSB). A Resv message
carries resource reservation information. Every node that receives a Resv message
creates a reservation state block (RSB) and allocates a label.
Figure 6-16 shows how RSVP-TE sets up a CR-LSP.
Figure 6-16 CR-SLP setup through RSVP-TE
1
if1
PE1
1.
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2
Path
if0
Resv
6
if1
P1
3
Path
if0
Resv
5
Path
if1
P2
if0
Resv
4
PE2
PE1 uses CSPF to calculate a path from PE1 to PE2, on which the IP address of
every hop is specified. PE1 generates an explicit route object (ERO) with the IP
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address of each hop and adds the ERO in a Path message. PE1 then creates a
PSB and sends the Path message to P1 according to information in the ERO.
Table 6-5 describes objects carried in the Path message.
Table 6-5 Path message on PE1
2.
Object
Value
SESSION
Source: PE1-if1; Destination: PE2-if0
RSVP_HOP
PE1-if1
EXPLICIT_ROUTE
P1-if0; P2-if0; PE2-if0
LABEL
LABEL_REQUEST
After P1 receives the Path message, it parses the message and creates a PSB
according to information in the message. Then P1 updates the message and
sends it to P2 according to the ERO. Table 6-6 describes objects in the Path
message.
–
The RSVP_HOP object specifies the IP address of the outbound interface
through which a Path message is sent. Therefore, PE1 sets the RSVP_HOP
object to the IP address of the outbound interface toward P1, and P1 sets
the RSVP_HOP field to the IP address of the outbound interface toward
P2.
–
P1 deletes the local LSR ID and IP addresses of the inbound and
outbound interfaces from the ERO field in the Path message.
Table 6-6 Path message on P1
3.
Object
Value
SESSION
Source: PE1-if1; Destination: PE2-if0
RSVP_HOP
P1-if1
EXPLICIT_ROUTE
P2-if0; PE2-if0
LABEL
LABEL_REQUEST
After receiving the Path message, P2 creates a PSB according to information
in the message, updates the message, and then sends it to PE2 according to
the ERO field. Table 6-7 describes objects in the Path message.
Table 6-7 Path message on P2
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Object
Value
SESSION
Source: PE1-if1; Destination: PE2-if0
RSVP_HOP
P2-if1
EXPLICIT_ROUTE
PE2-if0
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Object
Value
LABEL
LABEL_REQUEST
After PE2 receives the Path message, PE2 knows that it is the egress of the
CR-LSP to be set up according to the Destination field in the Session object.
PE2 then allocates a label and reserves bandwidth, and generates a Resv
message based on the local PSB. The Resv message carries the label allocated
by PE2 and is sent to P2.
PE2 uses the address carried in the RSVP_HOP field of the received Path
message as the destination IP address of the Resv message. The Resv message
does not carry the ERO field because it is forwarded along the reverse path.
Table 6-8 describes objects in the Resv message.
If a Resv message carries the RESV_CONFIRM object, the receiver needs to send a
ResvConf message to the sender to confirm the resource reservation request.
Table 6-8 Resv message on PE2
5.
Object
Value
SESSION
Source: PE2-if0; Destination: PE1-if1
RSVP_HOP
PE2-if0
LABEL
3
RECORD_ROUTE
PE2-if0
When P2 receives the Resv message, P2 creates an RSB according to
information in the message, allocates a new label, updates the message, and
then sends it to P1. Table 6-9 describes objects in the Resv message.
Table 6-9 Resv message on P2
6.
Object
Value
SESSION
Source: PE2-if0; Destination: PE1-if1
RSVP_HOP
P2-if0
LABEL
17
RECORD_ROUTE
P2-if0; PE2-if0
After receiving the Resv message, P1 creates an RSB according to information
in the message, updates the message, and then sends it to PE1. Table 6-10
describes objects in the Resv message.
PE1 obtains the label allocated by P1 from the received Resv message.
Resources are successfully reserved and a CR-LSP is set up.
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Table 6-10 Resv message on P1
Object
Value
SESSION
Source: PE2-if0; Destination: PE1-if1
RSVP_HOP
P1-if0
LABEL
18
RECORD_ROUTE
P1-if0; P2-if0; PE2-if0
6.2.5.3 Maintenance of Dynamic CR-LSPs
Path Status Maintenance
Soft State
The Resource Reservation Protocol (RSVP) is a soft-state protocol. RSVP-TE
periodically updates RSVP messages to maintain the resource reservation states on
nodes.
Resource reservation states include the path state and the reservation state. RSVP
nodes along an established CR-LSP periodically send Path and Resv messages
(collectively called RSVP Refresh messages) to maintain the path and reservation
states. RSVP Refresh messages are used to synchronize path state block (PSB) and
reservation state block (RSB) between RSVP nodes. If an RSVP node does not
receive any Refresh message within a specified period, it deletes the path or
reservation state.
RSVP Refresh
RSVP sends its messages as IP datagrams, which cannot ensure a reliable delivery.
After a CR-LSP is set up, the soft state mechanism synchronizes the PSB and RSB
between RSVP neighbors. Each node periodically sends RSVP Refresh messages to
its upstream and downstream nodes.
Refresh messages carry information that has already been advertised. The Time
Value field in Refresh messages specifies the refresh interval.
If a node does not receive any Refresh message about a certain state block after
the specified refreshing intervals elapses, it deletes the state.
A node can send Path and Resv messages to its neighbors in any sequence.
RSVP Srefresh
In addition to state synchronization, RSVP Refresh messages can also be used to
detect reachability between RSVP neighbors and maintain RSVP neighbor
relationships. Because Path and Resv messages are large, sending many RSVP
Refresh messages to establish a large number of CR-LSPs consumes excess
network resources. RSVP Summary Refresh (Srefresh) can address this problem.
RSVP Srefresh is implemented based on extended objects and the following
mechanisms:
●
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Message_ID extension and retransmission
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The Message_ID extension extends objects carried in RSVP messages. Among
the objects, the Message_ID and Message_ID_ACK objects acknowledge
received RSVP messages to ensure reliable RSVP message delivery.
The Message_ID object can also provide the RSVP retransmission mechanism.
A node resets the retransmission timer (Rf seconds) after sending an RSVP
message carrying the Message_ID object. If the node receives no ACK
message within Rf seconds, the node retransmits an RSVP message after (1 +
Delta) x Rf seconds. The Delta value depends on rate at which the sender
increases the retransmission interval. The node keeps retransmitting the
message until it receives an ACK message or the retransmission count reaches
the threshold (retransmission multiplier).
●
Srefresh messages transmission
Srefresh messages can be sent instead of standard Path or Resv messages to
update RSVP states. These messages reduce the amount of information that
must be transmitted and processed for maintaining RSVP states. When
Srefresh messages are sent to update the RSVP states, standard Refresh
messages are suppressed.
Each Srefresh message carries a Message_ID object, which contains multiple
message IDs to identify the Path and Resv states to update. Srefresh
implementation depends on the Message_ID extension. Srefresh messages can
only update the states that have been advertised in Path and Resv messages
containing Message_ID objects.
When a node receives a Srefresh message, the node compares the
Message_ID in the message with that saved in the local PSB or RSB. If the two
Message_IDs match, the node updates the local state block, just like it
receives a standard Path or Resv message. If they do not match, the node
sends a Srefresh NACK message to the sender. Later, the node updates the
Message_ID and the state block based on the received Path or Resv message.
A Message_ID object contains a message identifier. When a CR-LSP changes,
the message identifier increases. A node compares the message identifier in
the received Path message with the message identifier saved in the local state
block. If they are the same, the node does not update the state block. If the
received message identifier is larger than the local message identifier, the
node updates the state block.
Error Signaling
RSVP-TE uses the following messages to advertise CR-LSP errors:
●
PathErr message: is sent by an RSVP node to its upstream node if an error
occurs while this node is processing a Path message. The message is
forwarded upstream by intermediate nodes and finally reaches the ingress
node.
●
ResvErr message: is sent by an RSVP node to its downstream node if an error
occurs while this node is processing a Resv message. The message is
forwarded downstream by intermediate nodes and finally reaches the egress
node.
Path Teardown
After the ingress node receives a PathErr message or an instruction to delete a CRLSP, it immediately sends a PathTear message downstream. After receiving this
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message, the downstream nodes tear down the CR-LSP and reply with a ResvTear
message.
The functions of PathTear and ResvTear messages are as follows:
●
PathTear message: is sent to delete path information and functions in the
opposite way to a Path message.
●
ResvTear message: is sent to delete the resource reservation state and
functions in the opposite way to a Resv message.
6.2.5.4 RSVP-TE Messages
Nodes on an MPLS TE network send RSVP-TE messages to exchange information.
RSVP Message Format
Each type of RSVP messages contains a common header, followed by multiple
objects with variable lengths and types. Figure 6-17 shows the format of RSVP
messages.
Figure 6-17 RSVP message format
Format of RSVP messages
0
4
Version
8
Flags
16
31
Message Type
RSVP Checksum
Reserved
RSVP Length
Send_TTL
Objects ( Variable )
Format of Objects
0
16
Length
24
Class_Number
31
C-Type
Object Content (Variable)
Table 6-11 describes each field in an RSVP message.
Table 6-11 Fields an RSVP message
Field
Length
Description
Version
4 bits
Indicates the RSVP version number. Currently, the
value is 1.
Flags
4 bits
Indicates the message flag. Generally, the value is 0.
RFC 2961 extends this field to identify whether
Summary Refresh (Srefresh) is supported. If Srefresh
is supported, the value of the Flags field is 0x01.
Message
Type
8 bits
Indicates RSVP messages type. For example, the
value 1 indicates a Path message, and the value 2
indicates a Resv message.
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Field
Length
Description
RSVP
Checksum
16 bits
Indicates the RSVP checksum. The value 0 indicates
that the checksum of messages is not checked
during transmission.
Send_TTL
8 bits
Indicates the TTL of an RSVP message. When a
node receives an RSVP message, it compares the
Send_TTL and the TTL in the IP header to calculate
the number of hops that the message has passed in
a non-RSVP area.
Reserved
8 bits
Indicates that the field is reserved.
RSVP
Length
16 bits
Indicates the total length of an RSVP message, in
bytes.
Objects
Variable
Indicates the objects in an RSVP message. Each
RSVP message contains multiple objects. The
carried objects vary in different types of messages.
Length
16 bits
Indicates the total length of an object, in bytes. The
value must be a multiple of 4, and the smallest
value is 4.
Class_Num
ber
8 bits
Identifies an object class. Each object class has a
name, such as SESSION, SENDER_TEMPLATE, or
TIME_VALUE.
C-Type
8 bits
Indicates an object type. Class-Number and C-Type
together identify an object.
Object
Content
Variable
Indicates the content of an object.
Path Message
RSVP-TE uses Path messages to create RSVP sessions and to maintain path states.
A Path message is sent from the ingress node to the egress node. A path state
block (PSB) is created on each node the Path message passes.
The source IP address of a Path message is the LSR ID of the ingress node and the
destination IP address is the LSR ID of the egress node.
Table 6-12 lists some of the objects carried in a Path message.
Table 6-12 Objects in a Path message
Object
Class_Num
ber
C-Type
Object Content
SESSION
1
1
Carries RSVP session information,
such as the destination address,
tunnel ID, and extend tunnel ID.
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Object
Class_Num
ber
C-Type
Object Content
RSVP_HOP
3
1
Carries the IP address and index of
the outbound interface on the
previous hop that sends the Path
message.
TIME_VALU
E
5
1
Carries the refresh interval.
SENDER_TE
MPLATE
11
1
Carries the sender IP address and
LSP ID.
SENDER_TS
PEC
12
2
Specifies the traffic characteristics
of a data flow.
LABEL_REQ
UEST
19
1
Indicates that label binding is
requested for the path. This object
is carried only in Path messages.
ADSPEC
13
2
Collects QoS parameters of a path,
such as estimated path bandwidth,
minimal path delay, and path MTU.
EXPLICIT_R
OUTE
20
1
Specifies the path through which
an LSP passes. The path can be a
strict or loose explicit path. Path
messages are then forwarded along
the specified Explicit Route Object
(ERO). Path message transmission
is not restricted by IGP shortest
path.
RECORD_RO
UTE
21
1
Lists the label switching routers
(LSRs) that the Path message
passes. The Record Route Object
(RRO) can be used to collect path
information and discover routing
loops. It can also be copied to the
next Path message to implement
Route pinning.
SESSION_AT
TRIBUTE
207
● 1:
LSP_TUN
NEL_RA
Specifies the setup priority, holding
priority, reservation style, affinity,
and other attributes.
● 7: LSP
Tunnel
Resv Message
After receiving a Path message, the egress node returns a Resv message. The Resv
message carries resource reservation information and is sent hop-by-hop to the
ingress node. Each intermediate node creates and maintains a reservation state
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block (RSB) and allocates a label. When the Resv message reaches the ingress
node, an LSP is set up successfully.
Table 6-13 describes objects in a Resv message.
Table 6-13 Objects in a Resv message
Object
Class_Num
ber
C-Type
Object Content
INTEGRITY
4
1
Carries the authentication key of
the RSVP message.
SESSION
1
1
Carries RSVP session information,
such as the destination address,
tunnel ID, and extend tunnel ID.
RSVP_HOP
3
1
Carries the IP address and the
index of the outbound interface
that sends the Resv message.
TIME_VALU
E
5
1
Carries the refresh interval. The
default value is 30s.
STYLE
8
1
Carries the resource reservation
style, which is specified on the
ingress node.
FLOW_SPEC
9
● 1:
Reserved
(obsolete
)
flowspec
object
Specifies QoS characteristics of a
data flow.
● 2: Invserv
flowspec
object
FILTER_SPEC
10
1
Carries the sender IP address and
LSP ID.
RECORD_RO
UTE
21
1
Collects the inbound interface IP
address, LSR-ID, and outbound
interface IP address of each node
along the path.
LABEL
16
1
Carries the assigned label.
RESV_CONF
IRM
15
1
Indicates a confirmation of the
resource reservation request. This
object carries the IP address of the
node that requests resource
reservation confirmation.
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Reservation Styles
A reservation style is the method that an RSVP node uses to reserve resources
after receiving a resource reservation request from the upstream node. The
following reservation styles are supported:
●
Fixed Filter (FF) style: creates an exclusive reservation for each sender. A
sender does not share its resource reservation with other senders, and each
CR-LSP on a link has a separate resource reservation.
●
Shared Explicit (SE) style: creates a single reservation for a series of selected
upstream senders. CR-LSPs on a link share the same resource reservation.
6.2.6 Traffic Forwarding
Directing Traffic to an MPLS TE Tunnel
A CR-LSP of an MPLS TE tunnel can be established through information
advertisement, path calculation, and path setup. Unlike an LDP LSP, a CR-LSP
cannot automatically direct traffic to the MPLS TE tunnel. The following methods
can be used to direct traffic to the CR-LSP:
●
Static Route: applies to networks with simple or stable network topologies.
●
Tunnel Policy: applies to scenarios where TE VPN services are transmitted
over TE tunnels.
●
Auto Route: applies to networks with complex or variable network
topologies.
Static Route
The simplest method to direct traffic to an MPLS TE tunnel is to configure a static
route and specify a TE tunnel interface as the outbound interface.
Tunnel Policy
By default, VPN traffic is forwarded over LSP tunnels but not MPLS TE tunnels.
Either of the following tunnel policies can be used to direct VPN traffic to MPLS TE
tunnels:
●
Select-seq policy: selects a TE tunnel to transmit VPN traffic on the public
network by configuring an appropriate tunnel selection sequence.
●
Tunnel binding policy: binds a TE tunnel to a destination address to provide
QoS guarantee.
Auto Route
The auto route feature allows a TE tunnel to participate in IGP route calculations
as a logical link. The tunnel interface is used as the outbound interface of the
route. The tunnel is considered a point-to-point (P2P) link with a specified metric.
Two auto route types are available:
●
IGP shortcut: An LSP tunnel is not advertised to neighbor nodes, so it will not
be used by other nodes.
●
Forwarding adjacency: An LSP tunnel is advertised to neighboring nodes, so it
can be used by these nodes.
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Forwarding adjacency allows tunnel information to be advertised based on
IGP neighbor relationships.
To use the forwarding adjacency feature, nodes on both ends of a tunnel must
be located in the same area.
The following example shows the differences between IGP shortcut and
forwarding adjacency.
Figure 6-18 IGP shortcut and forwarding adjacency
Switch_8
Switch_3
Switch_4
10
10
10
5
10
10
10
Switch_2
TE
MPL Metric=1
0
S TE
Tunn
el1
Switch_5
10
Switch_1
Switch_6
Node
Mode
Switch_5
IGP Shortcut
Switch_7
Switch_5
Forwarding
Adjacency
Switch_7
Switch_7
Destination
Nexthop
Cost
Switch_2
Switch_4
25
Switch_1
Switch_4
35
Switch_2
Tunnel1
10
Switch_1
Tunnel1
20
Switch_2
Switch_7
20
Switch_1
Switch_7
30
Switch_2
Tunnel1
10
Switch_1
Tunnel1
20
In Figure 6-18, Switch_7 sets up an MPLS TE tunnel to Switch_2 over the path
Switch_7 -> Switch_6 -> Switch_2. The TE metrics of the links are shown in the
figure. On Switch_5 and Switch_7, routes to Switch_2 and Switch_1 differ
depending on the auto route configuration:
●
If auto route is not configured, Switch_5 uses Switch_4 as the next hop, and
Switch_7 uses Switch_6 as the next hop.
●
If auto route is used:
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–
When Tunnel1 is advertised using IGP shortcut, Switch_5 uses Switch_4 as
the next hop, and Switch_7 uses Tunnel1 as the next hop. Because
Tunnel1 is not advertised to Switch_5, only Switch_7 selects Tunnel1 using
the IGP.
–
When Tunnel1 is advertised using forwarding adjacency, Switch_5 uses
Switch_7 as the next hop, and Switch_7 uses Tunnel1 as the next hop.
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Because Tunnel1 is advertised to Switch_5 and Switch_7, both the two
nodes select Tunnel1 using the IGP.
6.2.7 Tunnel Reoptimization
The MPLS TE tunnel reoptimization function enables the ingress node to
automatically optimize the path of an MPLS TE tunnel when topology information
is updated. This function ensures that an MPLS TE tunnel always uses the optimal
path.
Background
MPLS TE tunnels are used to optimize traffic distribution on a network. An MPLS
TE tunnel is configured using the initial bandwidth required for services and initial
network topology. The network topology often changes, so the ingress node may
not use the optimal path to forward MPLS packets, causing a waste of network
resources. MPLS TE tunnels need to be optimized after being established.
Implementation
A specific event that occurs on the ingress node can trigger optimization of a CRLSP. The optimization enables the CR-LSP to be reestablished over the optimal
path with the smallest metric.
● The FF reservation style and tunnel reoptimization cannot be configured together.
● Reoptimization cannot be performed for a CR-LSP that is established over an explicit
path.
Reoptimization is implemented in either of the following modes:
●
Automatic mode
When the configured reoptimization interval expires, the ingress node uses
the Constrained Shortest Path First (CSPF) algorithm to calculate a new path.
If the calculated path has a smaller metric than the existing path, a CR-LSP is
set up over the new path. After the CR-LSP is successfully set up, the ingress
node instructs the forwarding plane to switch traffic to the new CR-LSP and to
tear down the original CR-LSP. After the original CR-LSP is torn down,
reoptimization is complete. If the CR-LSP fails to be set up, traffic is still
forwarded along the existing CR-LSP.
●
Manual mode
An administrator can run a reoptimization command to trigger
reoptimization.
The Make-Before-Break mechanism is used to ensure nonstop service
transmission during reoptimization. Traffic must switch to a new CR-LSP before
the original CR-LSP is torn down.
6.2.8 MPLS TE Security
RSVP authentication verifies digest messages carried in RSVP messages to defend
against attacks initiated by modified or forged messages. Authentication
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sequencing. RSVP authentication and its enhancements improve MPLS TE network
security.
Background
RSVP uses raw IP to transmit packets. Raw IP has no security mechanism and is
prone to attacks. RSVP authentication verifies packets using keys to prevent
attacks. When the local RSVP router receives a packet with a sequence number
smaller than the local maximum sequence number, the neighbor relationship is
terminated.
Key authentication cannot prevent replay attacks or neighbor relationship
termination resulting from RSVP message mis-sequencing. The RSVP
authentication enhancements are used to address these problems. RSVP
authentication enhancements add authentication lifetime, handshake, and
message window mechanisms to enhance RSVP security. The enhancements also
improve RSVP's capability to verify neighbor relationships in a harsh network
environment, such as a congested network.
Concepts
●
Raw IP: Similar to User Datagram Protocol (UDP), raw IP is unreliable because
it has no control mechanism to determine whether raw IP datagrams reach
their destinations.
●
Spoofing attack: An unauthorized router establishes a neighbor relationship
with a local router or sends pseudo RSVP messages to attack the local router.
(For example, requesting the local router to reserve a lot of bandwidth.)
●
Replay attack: A remote RSVP router continuously sends packets with
sequence numbers smaller than the maximum sequence number on a local
RSVP router. Then the local router terminates the RSVP neighbor relationship
with the remote RSVP router and the established CR-LSP is torn down.
Implementation
●
Key authentication
RSVP authentication protects RSVP nodes from spoofing attacks by verifying
keys in packets exchanged between neighboring nodes. The same key must
be configured on two neighboring nodes before they perform RSVP
authentication. A local node uses the configured key and the Keyed-Hashing
for Message Authentication Message Digest 5 (HMAC-MD5) algorithm to
calculate a digest for a message, adds this digest as an integrity object into
the message, and then sends the message to the remote node. After the
remote node receives the message, it uses the same key and algorithm to
calculate a digest and checks whether the local digest is the same as the
received one. If they match, the remote node accepts the message. If they do
not match, the remote node discards the message.
●
Authentication lifetime
The authentication lifetime specifies the period during which the RSVP
neighbor relationship is retained and provides the following functions:
–
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Controls the lifetime of an RSVP neighbor relationship when no CR-LSP
exists between the RSVP neighbors. The RSVP neighbor relationship is
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retained until the RSVP authentication lifetime expires. The RSVP-TE
authentication lifetime does not affect the status of existing CR-LSPs.
–
●
Prevents continuous RSVP authentication. For example, after RSVP
authentication is enabled between RTA and RTB, RTA continuously sends
tampered RSVP messages with an incorrect key to RTB. As a result, RTB
continuously discards the messages. The authentication relationship
between neighbors, however, cannot be terminated. The authentication
lifetime can prevent this situation. When neighbors receive valid RSVP
messages within the lifetime, the RSVP authentication lifetime is reset.
Otherwise, the authentication relationship is deleted after the
authentication lifetime expires.
Handshake mechanism
The handshake mechanism maintains the RSVP authentication status. After
neighboring nodes authenticate each other, they exchange handshake
packets. If they accept the packets, they record a successful handshake. If a
local node receives a packet with a sequence number smaller than the local
maximum sequence number, the local node processes the packet as follows:
●
–
Discards the packet if it shows that the handshake mechanism is not
enabled on the remote node.
–
Discards the packet if it shows that the handshake mechanism is enabled
on the remote node and the local node has a record about a successful
handshake. If the local node does not have a record of a successful
handshake with the remote node, this packet becomes the first to arrive
at the local node and the local node starts a handshake process.
Message window
A message window saves the received RSVP messages. If the window size is 1,
the system saves only the largest sequence number. If the window size is set
to a value greater than 1, the system saves the specified number of largest
sequence numbers. For example, the window size is set to 10, and the largest
sequence number of received RSVP messages is 80. The sequence numbers
from 71 to 80 can be saved if there is no packet mis-sequencing. If packet
mis-sequencing occurs, the local node sequences the messages and records
the 10 largest sequence numbers.
When the window size is not 1, the local RSVP node considers the RSVP
message received from the neighboring node as a valid message in either of
the following situations:
–
The sequence number in the received RSVP message is larger than the
maximum sequence number in the window.
–
The RSVP message carries an original sequence number that is larger
than the minimum sequence number in the window but is not saved in
the window.
The local RSVP node then adds the sequence number of the received RSVP
message to the window and processes the RSVP message. If the sequence
number is larger than the maximum sequence number in the window, the
local RSVP node deletes the minimum sequence number in the window. If the
sequence number is smaller than the minimum sequence number in the
window or already exists in the window, the local RSVP node discards the
RSVP message.
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By default, the window size is 1. The handshake mechanism works when the window size
is 1. If the window size is not 1, the handshake mechanism is affected. When the local
RSVP node receives an RSVP message with a sequence number smaller than the local
maximum sequence number, either of the following situations occurs:
●
If the sequence number of the received RSVP message is larger than the minimum
sequence number in the window and is not saved in the window, the local RSVP node
correctly processes the RSVP message.
●
If the sequence number already exists in the window, the local RSVP node discards
the RSVP message.
●
If the sequence number is smaller than the minimum sequence number in the
window, RSVP determines whether both ends are enabled with the handshake
mechanism. If either one is not enabled with the handshake mechanism, the system
discards the RSVP message. If both ends are enabled with the handshake mechanism,
the local and remote ends start the handshake process again and discard the RSVP
message.
For example, the window size is 10, and the window stores sequence numbers 71, 75, and
80. If the local RSVP node receives an RSVP message with sequence number 72, it adds the
sequence number to the window and correctly processes the RSVP message. If the local
RSVP node receives an RSVP message with sequence number 75, it directly discards the
RSVP message. If the local RSVP node receives an RSVP message with sequence number
70, RSVP determines whether both ends are enabled with the handshake mechanism. The
local and remote ends start the handshake process again only when they are both enabled
with the handshake mechanism.
RSVP Key Management Modes
RSVP keys can be managed in either of the following modes:
●
MD5 key
An MD5 key is entered in either cipher text or plain text. The MD5 algorithm
has the following characteristics:
●
–
Each protocol is configured with a separate key and cannot share a key
with another protocol.
–
An interface or a node is assigned only one key. To change the key, you
must delete the original key and configure a new one.
Keychain key
Keychain is an enhanced encryption algorithm. It allows you to define a group
of passwords to form a password string, and to specify encryption and
decryption algorithms and a validity period for each password. When the
system sends or receives a packet, the system selects a valid password. Within
the validity period of the password, the system uses the encryption algorithm
configured for the password to encrypt the packet before sending it out, or
the system uses the decryption algorithm configured for the password to
decrypt the packet after receiving it. In addition, the system uses a new
password after the previous one expires, minimizing the risks of password
cracking.
Keychain has the following characteristics:
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–
A keychain authentication password and the encryption and decryption
algorithms must be configured. The password validity period can also be
configured.
–
Keychain settings can be shared by protocols and managed uniformly.
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Keychain can be used on an RSVP interface or node and supports only HMACMD5.
NOTICE
MD5 key cannot ensure key. You are advised to use Keychain key.
RSVP Authentication Modes
RSVP defines the following authentication modes:
●
Neighbor-oriented authentication
You can configure authentication information, such as authentication keys,
based on different neighbor addresses. RSVP then authenticates each
neighbor separately.
A neighbor address can be either of the following:
●
–
IP address of an interface on an RSVP neighboring node
–
LSR ID of an RSVP neighboring node
Interface-oriented authentication
Authentication is configured on interfaces, and RSVP authenticates messages
based on inbound interfaces.
Neighbor-oriented authentication takes precedence over interface-oriented
authentication. A node discards messages if neighbor-oriented authentication fails,
and performs interface-oriented authentication only if neighbor-oriented
authentication is not enabled.
6.2.9 MPLS TE Reliability
6.2.9.1 Overview of MPLS TE Reliability
MPLS TE reliability technologies are necessary for the following reasons:
●
If attributes of a working MPLS TE tunnel, such as bandwidth, are modified, a
new path is set up for the tunnel using modified attributes, and service traffic
is switched to the new path. Reliability technologies are required to prevent or
minimize packet loss in the process.
●
If a node or link on a working MPLS TE tunnel fails, reliability technologies
are required to set up a backup CR-LSP and switch traffic to the backup CRLSP, while minimizing packet loss in this process.
●
When a node on a working MPLS TE tunnel encounters a control plane failure
but its forwarding plane is still working properly, reliability technologies are
required to ensure nonstop traffic forwarding during fault recovery on the
control plane.
MPLS TE provides multiple reliability technologies to ensure high reliability of key
services transmitted over MPLS TE tunnels. Table 6-14 describes these reliability
technologies.
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Table 6-14 MPLS TE reliability technologies
Reliability
Technology
Description
Function
Tunnel
attribute
update
reliability
Ensures reliable traffic transmission
when a CR-LSP is set up because of
attribute updates.
● Make-BeforeBreak
Fault
detection
Rapidly detects MPLS TE network faults
and triggers protection switching.
● RSVP Hello
Traffic
protection
Network-level reliability: provides endto-end path protection and local
protection.
● BFD for MPLS TE
● CR-LSP Backup
● TE FRR
● SRLG
● TE Tunnel
Protection Group
Device-level reliability: ensures that
nonstop forwarding when the control
plane fails on a node.
● RSVP GR
6.2.9.2 Make-Before-Break
The make-before-break mechanism prevents traffic loss during a traffic switchover
between two CR-LSPs. This mechanism improves MPLS TE tunnel reliability.
Background
Any change in link or tunnel attributes causes a CR-LSP to be reestablished using
new attributes. Traffic is then switched from the previous CR-LSP to the new CRLSP. If a traffic switchover is triggered before the new CR-LSP is set up, some
traffic is lost. The make-before-break mechanism prevents traffic loss.
Implementation
The make-before-break mechanism sets up a new CR-LSP and switches traffic to it
before the original CR-LSP is torn down. This mechanism helps minimize data loss
and reduces bandwidth consumption. Make-before-break is implemented using
the shared explicit (SE) resource reservation style.
The new CR-LSP may compete with the original CR-LSP for bandwidth on some
shared links. The new CR-LSP cannot be established if it fails the competition. The
make-before-break mechanism allows the system to reserve bandwidth used by
the original CR-LSP for the new one, without calculating the reserved bandwidth
on shared links. Additional bandwidth is required if links on the new path do not
overlap the links on the original path.
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Figure 6-19 Make-before-break mechanism
Path1
Switch_1
Switch_2
Switch_3
Switch_4
Path2
Switch_5
In Figure 6-19, the maximum reservable bandwidth on each link is 60 Mbit/s. A
CR-LSP has been set up along Path 1 (Switch_1 -> Switch_2 -> Switch_3 ->
Switch_4) with the bandwidth of 40 Mbit/s.
A new CR-LSP needs to be set up along Path 2 (Switch_1 -> Switch_5 -> Switch_3 > Switch_4) to forward data through the lightly loaded Switch_5. The available
bandwidth of the link Switch_3 -> Switch_4 is only 20 Mbit/s, not enough for the
new path. The make-before-break mechanism can be used in this situation to
allow the new CR-LSP to use the bandwidth of the link between Switch_3 and
Switch_4 reserved for the original CR-LSP. After the new CR-LSP is established,
traffic switches to the new CR-LSP, and the original CR-LSP is torn down.
The make-before-break mechanism can also be used to increase tunnel
bandwidth. If the reservable bandwidth of a shared link increases to the required
value, a new CR-LSP can be established.
On the network shown in Figure 6-19, the maximum reservable bandwidth on
each link is 60 Mbit/s. A CR-LSP has been set up along Path 1 with the bandwidth
of 30 Mbit/s.
A new CR-LSP needs to be set up along Path 2 to forward data through the lightly
loaded Switch_5, and the path bandwidth needs to increase to 40 Mbit/s. The
available bandwidth of the link Switch_3 -> Switch_4 is only 30 Mbit/s. The makebefore-break mechanism can be used in this situation. This mechanism allows the
new CR-LSP to use the bandwidth of the link between Switch_3 and Switch_4
reserved for the original CR-LSP, and reserves an additional bandwidth of 10
Mbit/s for the new path. After the new CR-LSP is set up, traffic is switched to the
new CR-LSP, and the original CR-LSP is torn down.
Switching and Deletion Delays
If a node is busy but its upstream or downstream node is idle, a CR-LSP may be
torn down before a new CR-LSP is established, causing a temporary traffic
interruption.
The make-before-break mechanism uses switching and deletion delay timers to
prevent temporary traffic interruption. When the two timers are configured, the
system switches traffic to a new CR-LSP after the switching delay time, and then
deletes the original CR-LSP after the deletion delay time.
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6.2.9.3 RSVP Hello
RSVP Hello mechanism is used to rapidly detect reachability between RSVP nodes
and trigger path protection provided by TE FRR. In addition, a node can use the
RSVP Hello mechanism to detect whether a neighboring node is in Restart state so
it can help the neighboring node in implementing RSVP GR.
Background
RSVP Refresh messages can synchronize PSB and RSB between nodes, monitor
reachability between RSVP neighbors, and maintain RSVP neighbor relationships.
This soft state mechanism detects neighbor relationships using Path and Resv
messages. The detection speed is low and a link failure cannot promptly trigger a
service traffic switchover. RSVP Hello is introduced to solve this problem.
Implementation
RSVP Hello is implemented as follows:
1.
Hello handshake
Figure 6-20 Hello handshake mechanism
Hello Repuest
LSRA
Hello ACK
LSRB
As shown in Figure 6-20, LSRA and LSRB are directly connected.
2.
–
When RSVP Hello is enabled on the interface of LSRA, LSRA sends a Hello
Request message to LSRB.
–
If LSRB is enabled with RSVP Hello, LSRB replies to LSRA with a Hello
ACK message after receiving the Hello Request message.
–
After LSRA receives the Hello ACK message from LSRB, LSRA determines
that the neighbor LSRB is reachable.
Neighbor loss detection
After a successful Hello handshake, LSRA and LSRB exchange Hello messages.
If LSRA receives no Hello ACK message from LSRB after sending three
consecutive Hello Request messages to LSRB, LSRA considers the neighbor
LSRB lost. TE FRR is triggered and LSRA restarts an RSVP Hello handshake.
3.
Neighbor restart detection
After LSRA detects the loss of the neighbor LSRB (they are both RSVP GR
capable), LSRA waits for the Hello Request message carrying a GR extension
from LSRB. After receiving this message, LSRA helps LSRB restore RSVP state
information and sends a Hello ACK message to LSRB. LSRB receives the Hello
ACK message from LSRA and knows that LSRA is helping it implement GR.
LSRA and LSRB exchange Hello messages to maintain the restored GR status.
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When LSRA and LSRB are located on the same CR-LSP:
●
If GR is disabled but TE FRR is enabled on LSRA, LSRA switches traffic to the bypass
CR-LSP to ensure uninterrupted traffic transmission when detecting loss of the
neighbor LSRB.
●
If GR is enabled on LSRA, LSRA preferentially uses RSVP GR to ensure uninterrupted
traffic transmission on the forwarding plane upon a control plane failure.
Usage Scenario
RSVP Hello applies to scenarios with TE FRR or RSVP GR enabled.
6.2.9.4 CR-LSP Backup
CR-LSP backup provides end-to-end protection for an MPLS TE tunnel. If the
ingress node detects a failure of the primary CR-LSP, it switches traffic to a backup
CR-LSP. After the primary CR-LSP recovers, traffic switches back to the primary CRLSP.
Concepts
CR-LSP backup functions include hot standby, ordinary backup, and the best-effort
path:
●
Hot standby: A hot-standby CR-LSP is set up immediately after the primary
CR-LSP is set up. When the primary CR-LSP fails, traffic switches to the hotstandby CR-LSP.
●
Ordinary backup: An ordinary backup CR-LSP can be set up only after a
primary CR-LSP fails. The ordinary backup CR-LSP takes over traffic when the
primary CR-LSP fails.
●
Best-effort path: If both the primary and backup CR-LSPs fail, a best-effort
path is set up and takes over traffic.
In Figure 6-21, the primary CR-LSP is set up over the path PE1 -> P1 -> P2 ->
PE2, and the backup CR-LSP is set up over the path PE1 -> P3 -> PE2. When
both CR-LSPs fail, PE1 sets up a best-effort path PE1 -> P4 -> PE2 to take over
traffic.
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Figure 6-21 Best-effort path
P3
Backup CR-LSP
PE1
P1
Primary
CR-LSP
P2
PE2
Best-effort
path
P4
A best-effort path has no bandwidth reserved for traffic, but has an affinity and a hop
limit configured to control the nodes it passes.
Implementation
The process of CR-LSP backup is as follows:
1.
CR-LSP backup deployment
Determine the paths, bandwidth values, and deployment modes. Table 6-15
lists CR-LSP backup deployment items.
Table 6-15 CR-LSP backup deployment
It
e
m
Hot Standby
Ordinary Backup
Best-Effort
Path
Pa
th
Determine whether the paths
of primary and hot-standby
CR-LSPs partially overlap. A
hot-standby CR-LSP can be
established over an explicit
path.
The path of an
ordinary CR-LSP can
partially overlap the
path of the primary
CR-LSP, no matter
whether the ordinary
CR-LSP is set up along
an explicit or implicit
path.
A best-effort
path is
automatically
calculated by
the ingress
node.
A hot-standby CR-LSP
supports the following
attributes:
● Explicit path
● Affinity attribute
● Hop limit
● Path overlapping
An ordinary backup
CR-LSP supports the
following attributes:
● Explicit path
● Affinity attribute
A best-effort
path supports
the following
attributes:
● Affinity
attribute
● Hop limit
● Hop limit
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It
e
m
Hot Standby
Ordinary Backup
Best-Effort
Path
Ba
nd
wi
dt
h
A hot-standby CR-LSP has the
same bandwidth as a primary
CR-LSP by default. Dynamic
bandwidth protection can
ensure that a hot-standby
CR-LSP does not use
additional bandwidth when it
is not transmitting traffic.
An ordinary backup
CR-LSP has the same
bandwidth as a
primary CR-LSP.
A best-effort
path is only a
protection
path that
does not have
reserved
bandwidth.
D
ep
lo
y
m
en
t
m
od
e
Can be established without
attribute templates.
Can be established
without attribute
templates.
Can be
established
without
attribute
templates.
Can be established using
attribute templates.
Can be established
using attribute
templates.
Automatically
established
and does not
support
attribute
templates.
Co
nfi
gu
ra
tio
n
co
m
bi
na
tio
n
● If a hot-standby CR-LSP is
established without an
attribute template, the
hot-standby CR-LSP can be
used together with a besteffort path to protect the
primary CR-LSP.
● If an ordinary CRLSP is established
without an
attribute template,
the ordinary CRLSP can only be
used alone to
protect the primary
CR-LSP.
-
● If a hot-standby CR-LSP is
established using an
attribute template, the
hot-standby CR-LSP can be
used together with an
ordinary backup CR-LSP
and a best-effort path to
protect the primary CRLSP.
● If an ordinary CRLSP is established
using an attribute
template, the
ordinary backup
CR-LSP can be used
together with a
hot-standby
backup CR-LSP and
a best-effort path
to protect the
primary CR-LSP.
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Table 6-16 CR-LSP backup modes
Backup
Mode
2.
Description
Advantage
Shortcoming
Hot standby
A hot-standby CR-LSP is
set up over a separate
path immediately after a
primary CR-LSP is set up.
A rapid traffic
switchover can
be performed.
If dynamic
bandwidth
adjustment is
disabled,
additional
bandwidth
needs to be
reserved for a
hot-standby
CR-LSP.
Ordinary
backup
The system attempts to
set up an ordinary
backup CR-LSP if a
primary CR-LSP fails.
No additional
bandwidth is
needed.
Ordinary
backup
performs a
traffic
switchover
slower than
hot standby.
Best-effort
path
The system establishes a
best-effort path over an
available path if both
the primary and backup
CR-LSPs fail.
Establishing a
best-effort path
is easy and a
few constraints
are needed.
Some quality
of service
(QoS)
requirements
cannot be met.
Backup CR-LSP setup
Multiple CR-LSP backup methods may be supported for a tunnel. The ingress
node uses these methods in turn until a CR-LSP is successfully established.
The rules for establishing a backup CR-LSP are as follows:
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a.
If new tunnel configuration is committed or a tunnel goes Down, the
ingress node attempts to establish a hot-standby CR-LSP, an ordinary
backup CR-LSP, and a best-effort path in turn, until a CR-LSP is
successfully established.
b.
A maximum of three CR-LSP attribute templates can be configured for
hot-standby CR-LSPs or ordinary backup CR-LSPs. These templates are
prioritized. The ingress node tries these templates in descending order of
priority until a CR-LSP is successfully established.
c.
If the status of a CR-LSP established using a lower-priority attribute
template changes, the ingress node attempts to establish a CR-LSP using
a higher-priority attribute template. The make-before-break mechanism
ensures nonstop traffic forwarding when a new CR-LSP is being
established.
d.
If a stable CR-LSP has been established using any of the attribute
templates, you can lock the used attribute template. After the attribute
template is locked, the ingress node will not use a higher-priority
attribute template to establish a CR-LSP. This locking function prevents
unnecessary traffic switchovers and lowers system costs.
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Currently, switches support the following backup modes and you can choose
one as required.
3.
–
Hot standby (manually configured)
–
Hot standby (manually configured) and best-effort path
–
Hot standby (configured using a TE attribute template)
–
Hot standby (configured using a TE attribute template) and ordinary
backup (configured using a TE attribute template)
–
Hot standby (configured using a TE attribute template) and best-effort
path
–
Hot standby (configured using a TE attribute template), ordinary backup
(configured using a TE attribute template), and best-effort path
–
Ordinary backup (manually configured)
–
Ordinary backup (configured using a TE attribute template)
–
Ordinary backup (configured using a TE attribute template) and besteffort path
–
Best-effort path
Backup CR-LSP attribute modification
If attributes of a backup CR-LSP are modified, the ingress node uses the
make-before-break mechanism to reestablish the backup CR-LSP with the
updated attributes. After that backup CR-LSP has been successfully
reestablished, traffic on the original backup CR-LSP (if it is transmitting
traffic) switches to this new backup CR-LSP, and then the original backup CRLSP is torn down.
4.
Fault detection
CR-LSP backup supports the following fault detection functions:
5.
–
Default error signaling mechanism of RSVP-TE: The fault detection speed
is relatively slow.
–
Bidirectional forwarding detection (BFD) for CR-LSP: This function is
recommended because it implements fast fault detection.
Traffic switchover
After the primary CR-LSP fails, the ingress node attempts to switch traffic
from the primary CR-LSP to a hot-standby CR-LSP. If the hot-standby CR-LSP
is unavailable, the ingress node attempts to switch traffic to an ordinary
backup CR-LSP. If the ordinary backup CR-LSP is unavailable, the ingress
attempts to switch traffic to a best-effort path.
6.
Traffic switchback
Traffic switches back to a path based on priorities of the available CR-LSPs.
Traffic will first switch to the primary CR-LSP. If the primary CR-LSP is
unavailable, traffic will switch to the hot-standby CR-LSP. The ordinary CR-LSP
has the lowest priority.
Dynamic Bandwidth Protection for Hot-standby CR-LSPs
Hot-standby CR-LSPs support dynamic bandwidth protection. The dynamic
bandwidth protection function allows a hot-standby CR-LSP to obtain bandwidth
resources only after the hot-standby CR-LSP takes over traffic from a faulty
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primary CR-LSP. This function improves bandwidth efficiency and reduces network
costs.
Dynamic bandwidth protection ensures that the hot-standby CR-LSP does not use
bandwidth when the primary CR-LSP is transmitting traffic. The dynamic
bandwidth protection process is as follows:
1.
If the primary CR-LSP fails, traffic immediately switches to the hot-standby
CR-LSP with 0 bit/s bandwidth. The ingress node uses the make-before-break
mechanism to establish a hot-standby CR-LSP.
2.
After the new hot-standby CR-LSP has been successfully established, the
ingress node switches traffic to this CR-LSP and tears down the hot-standby
CR-LSP with 0 bit/s bandwidth.
3.
After the primary CR-LSP recovers, traffic switches back to the primary CR-LSP.
The hot-standby CR-LSP then releases the bandwidth, and the ingress node
establishes another hot-standby CR-LSP with 0 bit/s bandwidth.
Path Overlapping for a Hot-standby CR-LSP
The path overlapping function can be configured for hot-standby CR-LSPs. This
function allows a hot-standby CR-LSP to use some links of a primary CR-LSP. After
the hot-standby CR-LSP is established, it can protect traffic on the primary CR-LSP.
6.2.9.5 TE FRR
Traffic engineering fast reroute (TE FRR) provides link protection and node
protection for MPLS TE tunnels. If a link or node fails, TE FRR rapidly switches
traffic to a backup path, minimizing traffic loss.
Background
A link or node failure triggers a primary/backup CR-LSP switchover. The switchover
is not completed until the IGP routes of the backup path converge, CSPF calculates
a new path, and a new CR-LSP is established. Traffic is lost during this process.
TE FRR technology can prevent traffic loss during a primary/backup CR-LSP
switchover. After a link or node fails, TE FRR establishes a CR-LSP that bypasses
the faulty link or node. The bypass CR-LSP can then rapidly take over traffic to
minimize loss. At the same time, the ingress node reestablishes a primary CR-LSP.
Concepts
Figure 6-22 Local protection
PLR
LSRA
Primary CR-LSP
LSRB
MP
LSRC
LSRD
Bypass CR-LSP
LSRE
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Table 6-17 explains the components shown in Figure 6-22.
Table 6-17 TE FRR concepts
Concept
Description
Primary CR-LSP
Protected CR-LSP.
Bypass CR-LSP
CR-LSP protecting the primary CR-LSP. A bypass CR-LSP is
usually in idle state and does not forward service traffics.
If the bypass CR-LSP is required to forward service data, it
must be assigned sufficient bandwidth.
PLR
Point of local repair, ingress node of a bypass CR-LSP. The
PLR can be the ingress node but not the egress node of
the primary CR-LSP.
MP
Merge point, egress node of a bypass CR-LSP. It must be
on the path of the primary CR-LSP but cannot be the
ingress node of the primary CR-LSP.
Table 6-18 describes TE FRR protection functions.
Table 6-18 TE FRR protection functions
Cla
ssif
ied
by
Type
Description
Pro
tect
ed
obj
ect
Link
protecti
on
In Figure 6-23 below, the primary CR-LSP passes through the
direct link between the PLR (LSRB) and MP (LSRC). Bypass LSP
1 can protect this link, which is called link protection.
Node
protecti
on
In Figure 6-23 below, the primary CR-LSP passes through LSRC
between the PLR (LSRB) and MP (LSRD). Bypass LSP 2 can
protect LSRC, which is called node protection.
Bandwi
dth
protecti
on
A bypass CR-LSP is assigned bandwidth higher than or equal to
the primary CR-LSP bandwidth, so that the bypass CR-LSP
protects the path and bandwidth of the primary CR-LSP.
Nonbandwi
dth
protecti
on
A bypass CR-LSP has no bandwidth and protects only the path
of the primary CR-LSP.
Manual
protecti
on
A bypass CR-LSP is manually configured and bound to a
primary CR-LSP.
Ban
dwi
dth
Im
ple
me
nta
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Cla
ssif
ied
by
Type
Description
tio
n
Auto
protecti
on
An auto FRR-enabled node automatically establishes a bypass
CR-LSP. The node binds the bypass CR-LSP to a primary CR-LSP
if the node receives an FRR protection request and the FRR
topology requirements are met.
Figure 6-23 TE FRR link and node protection
Primary CR-LSP
PLR
LSRB
MP
LSRC
MP
LSRD
LSRA
LSRE
LSRF
LSRG
LSRH
Bypass LSP 1
Bypass LSP 2
Link protection
Node protection
Link Fault
Node Fault
A bypass CR-LSP supports the combination of protection modes. For example, manual
protection, node protection, and bandwidth protection can be implemented together on a
bypass CR-LSP.
Implementation
TE FRR is implemented as follows:
1.
Setup of a primary CR-LSP
A primary CR-LSP is set up in the same way as a common CR-LSP except that
the ingress node adds flags into the SESSION_ATTRIBUTE object in a Path
message. For example, the local protection desired flag indicates that the
primary CR-LSP requires a bypass CR-LSP, and the bandwidth protection
desired flag indicates that the primary CR-LSP requires bandwidth protection.
2.
Binding between a bypass CR-LSP and the primary CR-LSP
FRR TE searches for a suitable bypass CR-LSP for the primary CR-LSP. A bypass
CR-LSP can be bound to a primary CR-LSP only if the primary CR-LSP has a
local protection desired flag. The binding process is completed before a CRLSP switchover.
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Before binding a bypass CR-LSP to a primary CR-LSP, the PLR must obtain the
following from the Record Route Object (RRO) in the received Resv message:
the outbound interface of the bypass CR-LSP, the next hop label forwarding
entry (NHLFE), the label switching router (LSR) ID of the MP, the label
allocated by the MP, and the protection type.
The PLR on the primary CR-LSP already knows its next hop (NHOP) and next
NHOP (NNHOP). If the egress LSR ID of the bypass CR-LSP is the same as the
NHOP LSR ID, the bypass CR-LSP provides link protection. If the egress LSR ID
of the bypass CR-LSP is the same as the NNHOP LSR ID, the bypass CR-LSP
provides node protection. In Figure 6-24, bypass LSP 1 protects the link
between LSRB and LSRC, and bypass LSP 2 protects the node between LSRB
and LSRD.
Figure 6-24 Binding between bypass and primary CR-LSPs
Primary CR-LSP
PLR
LSRB
NHOP
LSRC
NNHOP
LSRD
LSRA
LSRE
LSRF
Bypass CR-LSP 1
Link protection
LSRG
LSRH
Bypass CR-LSP 2
Node protection
Link Fault
Node Fault
If multiple bypass CR-LSPs are established, the PLR checks whether the bypass
CR-LSP protect bandwidth, their implementations, and protected objects in
sequence. Bypass CR-LSPs providing bandwidth protection are preferred over
those that do not provide bandwidth protection. Manual bypass CR-LSPs are
preferred over auto bypass CR-LSPs. Bypass CR-LSPs providing node protection
are preferred over those providing link protection. Figure 6-24 shows two
bypass CR-LSPs. If both the bypass CR-LSPs provide bandwidth protection and
are manually configured, bypass LSP 2 is bound to the primary CR-LSP.
(Bypass LSP 2 provides node protection, and bypass LSP 1 provides link
protection.) If bypass LSP 1 provides bandwidth protection but bypass LSP 2
does not, bypass LSP 1 is bound to the primary CR-LSP.
After the binding is complete, the primary CR-LSP's NHLFE records the bypass
CR-LSP's NHLFE index and an inner label that the MP allocates to the
upstream node on the primary CR-LSP. This label is used to forward traffic
during a primary/backup CR-LSP switchover.
3.
Fault detection
–
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Link protection uses a link layer protocol to detect and report faults. The
speed of fault detection at the link layer depends on the link type.
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Node protection uses a link layer protocol to detect link faults. If no fault
occurs on a link, RSVP Hello or BFD for RSVP is used to detect faults on
the protected node.
As soon as a link or node fault is detected, an FRR switchover is triggered.
● In node protection, only the link between the protected node and the PLR is
protected. The PLR cannot detect faults on the link between the protected node
and the MP.
● Link fault detection, BFD, and RSVP Hello mechanisms detect a failure at
descending speeds.
4.
Switchover
When the primary CR-LSP fails, service traffic and RSVP messages are
switched to the bypass CR-LSP, and the switchover event is advertised to the
upstream nodes. Upon receiving a data packet, the PLR pushes an inner label
and an outer label into the packet. The inner label is allocated by the MP to
the upstream node on the primary CR-LSP, and the outer label is allocated by
the next hop on the bypass CR-LSP to the PLR. The penultimate hop of the
bypass CR-LSP pops the outer label and forwards the packet with only the
inner label to the MP. The MP forwards the packet to the next hop along the
primary CR-LSP according to the inner label.
Figure 6-25 shows nodes on the primary and bypass CR-LSPs, labels allocated
to the nodes, and behaviors that the nodes perform. The bypass CR-LSP
provides node protection. If LSRC or the link between LSRB and LSRC fails, the
PLR (LSRB) swaps the inner label 1024 to 1022, pushes the outer label 34 into
a packet, and forwards the packet to the next hop along the bypass CR-LSP.
The lower part of Figure 6-25 shows the packet forwarding process after a TE
FRR switchover.
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Figure 6-25 Packet forwarding before and after a TE FRR switchover
Packet forwarding
before a TE FRR
switchover
Primary CR-LSP
LSRA
Bypass CR-LSP
PLR
MP
LSRB
1024
IP
Swap
Swap
LSRC
1025
IP
35
1022
IP
Swap
Swap
1022
IP
36
1022
IP
IP
Pop
Pop 36
Packet forwarding
after a TE FRR
switchover
34
1022
IP
LSRA
1024
IP
PLR
LSRB
LSRE
LSRD
MP
LSRC
1022
IP
LSRD
IP
LSRE
Swap 1024→1022
Push 34
label assigned for the
Primary CR-LSP
label assigned for the
Bypass CR-LSP
Link Fault
Node Fault
5.
Switchback
After a TE FRR switchover is complete, the ingress node of the primary CR-LSP
reestablishes the primary CR-LSP using the make-before-break mechanism.
Service traffic and RSVP messages are switched back to the primary CR-LSP
after the primary CR-LSP is successfully reestablished. The reestablished
primary CR-LSP is called a modified CR-LSP. The make-before-break
mechanism allows the original primary CR-LSP to be torn down only after the
modified CR-LSP is set up successfully.
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FRR does not take effect if multiple nodes fail simultaneously. After data is switched from
the primary CR-LSP to the bypass CR-LSP, the bypass CR-LSP must remain Up to ensure
data forwarding. If the bypass CR-LSP fails, the protected data cannot be forwarded using
MPLS, and the FRR function fails. Even if the bypass CR-LSP is reestablished, it cannot
forward data. Data forwarding will be restored only after the primary CR-LSP restores or is
reestablished.
Other Functions
●
N:1 protection
TE FRR supports N:1 protection mode, in which a bypass CR-LSP protects
multiple primary CR-LSPs.
Cooperation Between CR-LSP Backup and TE FRR
1.
2.
Combination of CR-LSP backup and TE FRR
–
CR-LSP ordinary backup and TE FRR: TE FRR can rapidly detect a link
failure and switch traffic to the bypass CR-LSP. When both primary and
bypass CR-LSPs fail, a backup CR-LSP is established to take over traffic.
–
CR-LSP hot standby and TE FRR: TE FRR can rapidly detect a link failure
and switch traffic to the bypass CR-LSP. Link failure information is then
sent to the tunnel ingress node through a signaling protocol and traffic is
switched to a backup CR-LSP.
Association between CR-LSP backup and TE FRR
After TE FRR local protection and backup CR-LSP end-to-end protection are
deployed, the system supports associated protection of bypass and backup
CR-LSPs. After association between CR-LSP backup and TE FRR is enabled:
–
If CR-LSP ordinary backup is enabled, the following situations occur:
When the protected link or node fails, TE FRR switches traffic to the
bypass CR-LSP and attempts to restore the primary CR-LSP and to set up
a backup CR-LSP.
After the backup CR-LSP is set up successfully but the primary CR-LSP has
not restored, traffic is switched to the backup CR-LSP.
After the primary CR-LSP restores successfully, traffic is switched back to
the primary CR-LSP, regardless of whether traffic is transmitted along the
bypass or backup CR-LSP.
If the backup CR-LSP fails to be set up and the primary CR-LSP is not
restored, traffic is transmitted along the bypass CR-LSP.
–
If CR-LSP hot standby is enabled, the following situations occur:
When the protected link or node fails and the backup CR-LSP is Up,
traffic is switched to the bypass CR-LSP and then immediately to the
backup CR-LSP. At the same time, the ingress node attempts to restore
the primary CR-LSP.
If the backup CR-LSP is Down, traffic is switched in the same manner as
in ordinary backup mode.
In CR-LSP hot standby mode, the ingress node attempts to set up a backup
CR-LSP while the primary CR-LSP is Up. After the backup CR-LSP is created
successfully, more bandwidth is occupied. In CR-LSP ordinary backup mode,
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the ingress node starts to set up a backup CR-LSP only when the primary CRLSP is in FRR-in-use state. No more bandwidth is occupied when the primary
CR-LSP is working properly. Therefore, association between CR-LSP ordinary
backup and TE FRR is recommended.
6.2.9.6 SRLG
Shared risk link group (SRLG) is a constraint to calculating a backup or a bypass
CR-LSP on a network with CR-LSP hot standby or TE FRR configured. SRLG
prevents bypass and primary CR-LSPs from being set up on links with the same
risk level, which enhances TE tunnel reliability.
Background
A network administrator often uses CR-LSP hot standby or TE FRR technology to
ensure MPLS TE tunnel reliability. However, CR-LSP hot standby or TE FRR may fail
in real-world application.
Figure 6-26 SRLG diagram
Path1
PE1
P1
P2
PE2
P2
PE2
Path2
Logical topology
P3
SRLG
PE1
P1
NE1
Physical topology
Optical transport
device
P3
Shared link
In Figure 6-26, Path 1 is the primary CR-LSP and Path 2 is the bypass CR-LSP. The
link between P1 and P2 requires TE FRR protection.
Core nodes P1, P2, and P3 on the backbone network are connected by a transport
network device. In Figure 6-26, the top diagram is an abstract version of the
actual topology below. NE1 is a transport network device. During network
construction and deployment, two core nodes may share links on the transport
network. For example, the yellow links in Figure 6-26 are shared by P1, P2, and
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P3. A shared link failure affects primary and bypass CR-LSPs and makes FRR
protection invalid. To enable TE FRR to protect the CR-LSP, bypass and primary CRLSPs must be set up over links of different risk levels. SRLG technology can be
deployed to meet this requirement.
However, an SRLG is a set of links that share the same risks. If one of the links
fails, other links in the group may fail as well. Therefore, protection fails even if
other links in the group function as the hot standby or bypass CR-LSP for the
failed link.
Implementation
SRLG is a link attribute, expressed by a numeric value. Links with the same SRLG
value belong to a single SRLG.
The SRLG value is advertised to the entire MPLS TE domain using IGP TE. Nodes in
a domain can then obtain SRLG values of all the links in the domain. The SRLG
value is used in CSPF calculations together with other constraints such as
bandwidth.
MPLS TE SRLG works in either of the following modes:
●
Strict mode: The SRLG value is a mandatory constraint when CSPF calculates
paths for hot standby and bypass CR-LSPs.
●
Preferred mode: The SRLG value is an optional constraint when CSPF
calculates paths for hot standby and bypass CR-LSPs. If CSPF fails to calculate
a path based on the SRLG value, CSPF excludes the SRLG value when
recalculating the path.
Usage Scenario
SRLG applies to networks with CR-LSP hot standby or TE FRR configured.
Benefits
SRLG constrains the path calculation for hot standby and bypass CR-LSPs, which
avoids primary and bypass CR-LSPs with the same risk level.
6.2.9.7 TE Tunnel Protection Group
A tunnel protection group provides end-to end protection for MPLS TE tunnels. If a
working tunnel in a protection group fails, traffic is switched to a protection
tunnel.
Concepts
Tunnel protection group concepts are as follows:
●
Working tunnel: protected tunnel.
●
Protection tunnel: tunnel that protects the working tunnel.
●
Protection switchover: If a working tunnel in a protection group fails, traffic is
rapidly switched to a protection tunnel, enhancing network reliability.
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Figure 6-27 Tunnel protection group
Working tunnel-1
LSRA
LSRB
Protection tunnel-3
Data flow when primary
tunnel is normal
Data flow when primary
tunnel is failed
Working tunnel-1 fails
As shown in Figure 6-27, on LSRA, tunnel-3 is specified as the protection tunnel
for working tunnel-1. When a failure of tunnel-1 is detected, the ingress node
switches traffic to protection tunnel-3. After tunnel-1 is restored, the system
determines whether to switch traffic back to the working tunnel according to the
configured switchback policy.
Implementation
A tunnel protection group uses a configured protection tunnel to protect a
working tunnel, improving tunnel reliability. Configuring working and protection
tunnels over separate links is recommended.
Table 6-19 describes the process of implementing a tunnel protection group.
Table 6-19 Tunnel protection group implementation
Step
Description
Tunnel
setup
The process of setting up working and protection tunnels is the
same as that of setting up a common tunnel. The working and
protection tunnels must have the same ingress and egress nodes.
Protection tunnel attributes, however, can differ from working
tunnel attributes. To better protect the working tunnel, configure
working and protection tunnels over separate links when deploying
a tunnel protection group.
NOTE
● The protection tunnel cannot be protected by any other protection tunnel
or enabled with TE FRR.
● You can configure independent attributes for the protection tunnel, which
facilitates network planning.
Binding
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After a tunnel protection group is configured for a working tunnel,
the protection tunnel with a specified tunnel ID is bound to the
working tunnel.
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Step
Description
Fault
detection
To implement fast protection switchover, the tunnel protection
group detects faults using the BFD for CR-LSP mechanism in
addition to MPLS TE's detection mechanism.
Protectio
n
switchov
er
The tunnel protection group supports the following switchover
modes:
● Manual switchover: A network administrator runs a command to
switch traffic.
● Auto switchover: The ingress node automatically switches traffic
when detecting a fault on the working tunnel.
In auto switchover mode, you can set the switchover period.
Switchba
ck
After the working tunnel is restored, the ingress node determines
whether to switch traffic back to the working tunnel according to
the configured switchback policy.
1:1 and N:1 Protection
A tunnel protection group works in either 1:1 or N:1 mode. The 1:1 mode enables
a protection tunnel to protect only one working tunnel. The N:1 mode enables a
protection tunnel to protect multiple working tunnels.
Figure 6-28 Tunnel protection group in N:1 mode
Working tunnel-1
LSRA
LSRB
Working tunnel-2
Protection tunnel-3
Data flow when primary
tunnel is normal
Data flow when primary
tunnel is failed
Differences Between CR-LSP Backup and Tunnel Protection Group
CR-LSP backup and tunnel protection group are both end-to-end protection
mechanisms for MPLS TE tunnels. Table 6-20 lists the differences between the
two mechanisms.
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Table 6-20 Differences between CR-LSP backup and tunnel protection group
Item
CR-LSP Backup
Tunnel Protection Group
Protected
object
Primary and backup CRLSPs are set up in the same
tunnel. The backup CR-LSP
protects the primary CR-LSP.
The protection tunnel protects
the working tunnel.
TE FRR
The primary CR-LSP
supports TE FRR while the
backup CR-LSP does not.
The working tunnel supports TE
FRR while the tunnel protection
does not.
LSP attributes
The primary and backup CRLSPs have the same
attributes (such as
bandwidth, setup priority,
and holding priority), except
the TE FRR attributes.
Attributes of tunnels in a tunnel
protection group are
independent from each other.
For example, a protection tunnel
without bandwidth can protect a
working tunnel requiring
bandwidth protection.
Protection
mode
Supports 1:1 protection
mode. Each primary CR-LSP
has a backup CR-LSP.
Supports 1:1 and N:1 protection
modes. A protection tunnel can
protect multiple working
tunnels. If a working tunnel fails,
data is switched to the shared
protection tunnel.
6.2.9.8 BFD for MPLS TE
Bidirectional Forwarding Detection (BFD) can quickly detect faults in an MPLS TE
tunnel and trigger a traffic switchover when a fault is detected, improving
network reliability.
Background
In most cases, MPLS TE uses TE FRR, CR-LSP backup, and TE tunnel protection
group to enhance network reliability. These technologies detect faults using the
RSVP Hello or RSVP Srefresh mechanism, but the detection speed is slow. When a
Layer 2 device such as a switch or hub exists between two nodes, the traffic
switchover speed is even slower, leading to traffic loss. BFD uses the fast packet
transmission mode to quickly detect faults on MPLS TE tunnels, so that a service
traffic switchover can be triggered quickly to better protect the MPLS TE service.
Concepts
Based on BFD session setup modes, BFD is classified into the following types:
●
Static BFD: Local and remote discriminators of BFD sessions are manually
configured.
●
Dynamic BFD: Local and remote discriminators of BFD sessions are
automatically allocated by the system.
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For details about BFD, see BFD Configuration in the S1720, S2700, S5700, and S6720
V200R011C10 Configuration Guide - Reliability.
Implementation
In MPLS TE, BFD is implemented in the following methods for different detection
scenarios:
●
BFD for RSVP
BFD for Resource Reservation Protocol (RSVP) detects faults on links between
RSVP nodes in milliseconds. BFD for RSVP applies to TE FRR networking
where a Layer 2 device exists between the PLR and its RSVP neighbor along
the primary CR-LSP.
●
BFD for CR-LSP
BFD for CR-LSP can rapidly detect faults on CR-LSPs and notify the forwarding
plane of the faults to ensure a fast traffic switchover. BFD for CR-LSP is
usually used together with a hot-standby CR-LSP or a tunnel protection
group.
●
BFD for TE Tunnel
When an MPLS TE tunnel functions as a virtual private network (VPN) tunnel
on the public network, BFD for TE tunnel detects faults in the entire TE
tunnel. This triggers traffic switchovers for VPN applications including VPN
FRR and virtual leased line (VLL) FRR.
BFD for RSVP
When Layer 2 devices exist between neighboring RSVP nodes, the two nodes can
detect a link failure based only on the RSVP Hello mechanism. Several seconds are
required to complete a switchover. This results in the loss of a great deal of data.
BFD for RSVP detects faults in milliseconds on links between RSVP neighboring
nodes. BFD for RSVP applies to the TE FRR networking where Layer 2 devices exist
between the PLR and its RSVP neighbor along the primary CR-LSP, as shown in
Figure 6-29.
Figure 6-29 BFD for RSVP
BFD Session
BFD Session
BFD Session
BFD Session
BFD for RSVP can share BFD sessions with BFD for OSPF, BFD for IS-IS, or BFD for
Border Gateway Protocol (BGP). Therefore, the local node selects the minimum
parameter values among the shared BFD session as the local BFD parameters. The
parameters include the transmit interval, the receive interval, and the local
detection multiplier.
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BFD for CR-LSP
BFD for CR-LSP can rapidly detect faults on CR-LSPs and notify the forwarding
plane of the faults to ensure a fast traffic switchover. BFD for CR-LSP usually
works with a hot-standby CR-LSP or tunnel protection group.
A BFD session is bound to a CR-LSP. That is, a BFD session is set up between
ingress and egress nodes. A BFD packet is sent by the ingress node and forwarded
to the egress node along a CR-LSP. The egress node then responds to the BFD
packet. The BFD session at the ingress node can rapidly detect the status of the
path through which the LSP passes.
Upon detecting a link failure, BFD notifies the forwarding plane of the failure. The
forwarding plane searches for a backup CR-LSP and switches traffic to it. The
forwarding plane then reports fault information to the control plane. If dynamic
BFD for CR-LSP is used, the control plane creates a BFD session for the backup CRLSP. If static BFD for CR-LSP is used, a BFD session can be configured for the
backup CR-LSP.
Figure 6-30 BFD for CR-LSP before and after a link fault occurs
LSRD
Before a link fault occurs
LSRA
LSRB
LSRC
LSRD
After a link fault occurs
Primary CR-LSP
Backup CR-LSP
LSRA
LSRB
LSRC
Bfd Session
Link fault
BFD for TE Tunnel
BFD detects faults in the entire TE tunnel and triggers traffic switchovers for VPN
applications such as VPN FRR.
BFD for CR-LSP notifies a TE tunnel of faults and triggers service switchovers
between CR-LSPs in the TE tunnel. Unlike BFD for CR-LSP, BFD for TE tunnel
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notifies VPN applications of faults and triggers service switchovers between TE
tunnel interfaces.
Differences
Table 6-21 lists differences among BFD for RSVP, BFD for CR-LSP, and BFD for TE
tunnel.
Table 6-21 Comparison of BFD for TE technologies
Detection
Technology
Detection
Object
Deployment
Position
Usage
Scenario
BFD Session
Mode
BFD for RSVP
RSVP
neighboring
relationship
Two
neighboring
nodes of an
RSVP session
Associating
with TE FRR
Dynamic
BFD for CRLSP
CR-LSP
Ingress and
egress nodes
Associating
with a hotstandby CRLSP or tunnel
protection
group
● Dynamic
BFD for TE
Tunnel
MPLS TE
tunnel
Ingress and
egress nodes
Associating
with VPN FRR
or VLL FRR
Static
● Static
6.2.9.9 RSVP GR
RSVP Graceful Restart (GR) ensures uninterrupted traffic transmission on the
forwarding plane when traffic is switched to the control plane upon a node failure.
Background
GR is typically applied to provider edge (PE) routers, especially when users
connect to the backbone network through a single PE router. If an MPLS TE tunnel
deployed on such a PE router for traffic engineering or as a VPN tunnel on the
public network, traffic on the tunnel is interrupted when the PE router fails or
undergoes an active/standby switchover for maintenance (software upgrade, for
example). As shown in Figure 6-31, RSVP GR can be deployed on PE3 to ensure
uninterrupted service forwarding when PE3 fails.
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Figure 6-31 RSVP GR application
VPNA
CE1
VPNA
CE2
PE1
PE2
Backbone
PE3
PE4
CE4
VPNB
CE3
VPNB
Concepts
RSVP GR is a fast state recovery mechanism for RSVP-TE. As one of the highreliability technologies, RSVP GR is designed based on non-stop forwarding (NSF).
The GR process involves GR restarter and GR helper routers. The GR restarter
restarts the protocol and the GR helper assists in the process.
RSVP GR provides the following types of messages:
●
Hello message with GR extensions: is used to detect the neighbor's GR status.
●
GR Path message: is sent downstream and carries information about the last
Path update.
●
Recovery Path message: is sent upstream and carries information about the
last received Path message.
Implementation
RSVP GR detects the GR status of a neighbor using RSVP Hello extensions.
RSVP GR is implemented as follows:
In Figure 6-32, after the GR restarter triggers a GR, it stops sending Hello
messages to its neighbors. If a GR helper does not receive Hello messages for
three consecutive intervals, it considers that the neighbor is performing a GR and
retains all forwarding information. Meanwhile, the GR restarter continue to
transmit services and to wait for the GR restarter to complete the process.
After the GR restarter starts, it receives Hello messages from neighbors and sends
Hello messages in response. Upstream and downstream nodes process Hello
messages in different ways:
●
When the upstream GR helper receives a Hello message, it sends a GR Path
message downstream to the GR restarter.
●
When the downstream GR helper receives a Hello message, it sends a
Recovery Path message upstream to the GR restarter.
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Figure 6-32 RSVP GR implementation
Upstream
Hello
GR-Helper
GR Path
Hello
GR-Restarter
Downstream
Recovery
Path
GR-Helper
When receiving the GR Path message and the Recovery Path message, the GR
restarter reestablishes the path state block (PSB) and reservation state block (RSB)
of the CR-LSP based on the two messages. Information about the CR-LSP on the
local control plane is restored.
If the downstream GR helper cannot send Recovery Path messages, the GR
restarter reestablishes the local PSB and RSB using only GR Path messages.
Usage Scenario
RSVP GR can be deployed to improve device-level reliability for nodes when an
MPLS TE tunnel is set up using RSVP TE.
Benefits
When an active/standby switchover occurs on the control plane, RSVP GR ensures
uninterrupted data transmission, improving device-level reliability.
6.3 MPLS TE Application on an IP MAN
Service Overview
Carriers are converging their service bearer networks. IP/MPLS technology is
essential on these converged networks because the technology allows voice, video,
leased line, and data services to be transmitted on an IP/MPLS backbone network.
Depending upon individual subscribers' requirements, services on a metropolitan
area network (MAN) are classified into:
●
For individual subscribers: high-speed Internet (HSI), video on demand (VoD),
and voice over IP (VoIP)
●
For business and enterprise subscribers: L3VPN services (business VPN) and
L2VPN services (data, video, and voice services)
Table 6-22 lists the requirements of these services.
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Table 6-22 Services on an IP MAN
Service
QoS
Requirement
s
Reliability
Requirements
Security Requirements
HSI
● Bandwidth
guarantee:
not
required
● End-to-end services:
Redundant links are
deployed to ensure
that traffic is
switched to the
backup link upon a
primary link failure.
● Services are isolated.
● QoS
guarantee:
low
VoD
● Bandwidth
guarantee:
required
● QoS
guarantee:
medium
VoIP
● Voice service: Traffic
is rapidly switched to
the backup link upon
a primary link failure
to ensure real-time
transmission.
● The IP infrastructure
can effectively
defend against
attacks and viruses,
ensuring stable
network operation.
● Bandwidth
guarantee:
required
● QoS
guarantee:
high
Business
VPN
● Bandwidth
guarantee:
required
● QoS
guarantee:
medium
Networking Description
Currently, an IP MAN consists of a MAN backbone and a MAN access network,
which deliver services to users. Figure 6-33 and Figure 6-34 show end-to-end
service models for individual and enterprise subscribers.
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Figure 6-33 Service model of an individual subscriber
BRAS
PE-AGG
HSI
DSLAM
IP/MPLS
MAN
VOIP
BackBone
UPE
PE-AGG
SR
SoftX
VOD
HSI
MPLS TE+VLL/VPLS
VoD/VoIP
MPLS TE+VLL/VPLS
Figure 6-34 Service model of an enterprise subscriber
BRAS
UPE
Enterprise
service
IP/MPLS
MAN
BackBone
SR
L3VPN or L2VPN
MPLS TE
MPLS TE Hot-standby
BFD for CR-LSP
Feature Deployment
Enterprise or individual services are core services that have bandwidth, QoS, and
reliability requirements. MPLS TE tunnels are recommended as VPN tunnels on the
public network to meet service requirements. For detailed deployment, see Table
6-23.
Table 6-23 MPLS TE deployment on an IP MAN
Item
L3VPN
L2VPN
Services
Business VPN
● HSI
● VoD
● VoIP
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Item
L3VPN
L2VPN
VPN tunnel
on the
public
network
MPLS TE tunnel
MPLS TE tunnel
Reliability
● Network reliability
● Network reliability
– Link protection: provided
using TE hot standby and
BFD for CR-LSP.
– Link protection: provided
using TE hot standby and
BFD for CR-LSP.
– Node protection:
provided using VPN FRR
and BFD for TE tunnel.
– Node protection: provided
using VLL FRR and BFD
for TE tunnel.
● Device reliability: RSVP GR.
● Device reliability: RSVP GR.
QoS
End-to-end QoS must be configured between a user-end provider
edge (UPE) and a broadband remote access server (BRAS) or
service router (SR) to ensure service quality.
Security
RSVP MD5 or keychain is used for authentication.
Key deployment points are as follows: Explicit paths are configured to separately
establish primary and backup CR-LSPs. The two paths do not overlap in important
areas.
6.4 Summary of MPLS TE Configuration Tasks
MPLS TE is implemented after an MPLS TE tunnel is created and traffic is
imported to the TE tunnel. To adjust MPLS TE parameters and deploy some
security solutions, perform one or more of the following operations: adjusting
RSVP-TE signaling parameters, adjusting the path of the CR-LSP, adjusting the
establishment of MPLS TE tunnels and CR-LSP backup, configuring MPLS TE FRR,
configuring MPLS TE tunnel protection group, configuring BFD for MPLS TE, and
configuring RSVP GR.
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Table 6-24 MPLS TE configuration tasks
Configuration
Task
Configuration
Description
Create an
MPLS TE
tunnel
To transmit L2VPN or L3VPN
services on the MPLS
backbone network, and
enable a tunnel to adapt to
network topology changes to
ensure stable data
transmission, create an MPLS
TE tunnel. MPLS TE tunnels
can be created using the
following methods:
6.7 Configuring a Static
MPLS TE Tunnel
6.8 Configuring a Dynamic
MPLS TE Tunnel
● Static MPLS TE Tunnels:
Static MPLS TE tunnels are
established using labels
that are allocated
manually but not by a
signaling protocol to send
control packets. Using
static MPLS TE tunnels is
recommended for a stable
network with lowperformance devices.
Static MPLS TE tunnels
have the highest priorities,
which means that their
bandwidth cannot be
preempted. Static MPLS TE
tunnels will not preempt
bandwidth of other types
of LSPs.
● Dynamic MPLS TE Tunnels:
Dynamic MPLS TE tunnels
are established using the
RSVP-TE signaling protocol
that can adjust the path of
an MPLS TE tunnel
according to network
changes. There is no need
to manually configure
each hop on a large scale
network.
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Configuration
Task
Configuration
Description
Configure the
MPLS TE
tunnel to
forward data
traffic
An MPLS TE tunnel does not
automatically direct traffic. To
enable traffic to travel along
an MPLS TE tunnel, use one
of the following methods to
import the traffic to the MPLS
TE tunnel:
6.9 Importing Traffic to an
MPLS TE Tunnel
● Use static routes
This is the simplest
method for importing the
traffic to an MPLS TE
tunnel.
● Use tunnel policies
In general, VPN traffic is
forwarded through an LSP
tunnel but not an MPLS TE
tunnel. To import VPN
traffic to the MPLS TE
tunnel, you need to
configure a tunnel policy.
● Use the auto route
mechanism
A TE tunnel is used as a
logical link for IGP route
calculation. A tunnel
interface is used as an
outbound interface of a
route.
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Configuration
Task
Configuration
Description
Adjust MPLS
TE parameters
You can adjust MPLS TE
parameters as required. The
parameters are listed as
follows:
6.10 Adjusting RSVP-TE
Signaling Parameters
● RSVP Signaling Parameters
6.12 Adjusting the
Establishment of an MPLS
TE Tunnel
RSVP signaling parameters
include the RSVP
reservation style,
reservation confirmation,
RSVP timer, summary
refresh, Hello extension
mechanism, and RSVP
authentication. You can
adjust these parameters to
meet customer
requirements.
6.11 Adjusting the Path of a
CR-LSP
● CR-LSP Selection
CSPF uses the TEDB and
constraints to calculate
appropriate paths and
establishes CR-LSPs
through the signaling
protocol. MPLS TE provides
multiple methods to
control CSPF calculation,
adjusting CR-LSP selection.
The methods include:
– Configuring the tiebreaking of CSPF
– Configuring the metric
for path calculation
– Configuring the CR-LSP
hop limit
– Configuring route
pinning
– Configuring
administrative group
and affinity property
– Configuring Shared Risk
Link Group (SRLG)
– Configuring the failed
link timer
● Establishment of MPLS TE
Tunnels
During the establishment
of an MPLS TE tunnel, you
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Task
Configuration
6 MPLS TE Configuration
Description
may need to perform
specified configurations in
practical applications.
MPLS TE provides multiple
methods to adjust
establishment of MPLS TE
tunnels. The methods
include:
– Performing loop
detection
– Configuring route
record and label record
– Configuring reoptimization for CR-LSP
– Configuring the tunnel
reestablishment
function
– Configuring the RSVP
signaling delay-trigger
function
– Configuring the tunnel
priority
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Configuration
Task
Configuration
Description
Configure
MPLS TE
reliability
MPLS TE provides multiple
reliability technologies to
ensure high reliability of key
services transmitted over
MPLS TE tunnels. The device
supports the following
reliability features for MPLS
TE tunnels:
6.13 Configuring CR-LSP
Backup
● CR-LSP backup
If a primary CR-LSP fails,
traffic rapidly switches to a
backup CR-LSP, ensuring
uninterrupted traffic
transmission.
● TE FRR
TE FRR is performed in
manual or automatic
mode:
– TE Manual FRR
It applies to scenarios
with simple network
topology.
6.16 Configuring Association
Between TE FRR and CR-LSP
Backup
6.14 Configuring Manual TE
FRR
6.15 Configuring Auto TE
FRR
6.17 Configuring a Tunnel
Protection Group
6.18 Configuring Dynamic
BFD for RSVP
6.19 Configuring Static BFD
for CR-LSPs
6.20 Configuring Dynamic
BFD for CR-LSPs
6.21 Configuring Static BFD
for TE Tunnels
6.22 Configuring RSVP GR
– TE Auto FRR
It applies to scenarios
with complicated
network topology.
● Tunnel protection group
The tunnel protection
group provides end-to end
protection for MPLS TE
tunnels. If a working
tunnel in a protection
group fails, traffic is
switched to a protection
tunnel.
● BFD for RSVP
BFD for RSVP applies to a
TE FRR network, on which
Layer 2 devices exist
between the PLR and its
RSVP neighboring nodes
over the primary CR-LSP.
● BFD for CR-LSP
BFD for CR-LSP is used
together with a hotIssue 10 (2019-12-30)
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Configuration
Description
standby CR-LSP or a tunnel
protection group.
● BFD for TE tunnel
BFD can monitor MPLS TE
tunnels that are used as
public network tunnels to
transmit VPN traffic.
● RSVP GR
RSVP graceful restart (GR)
is a state recovery
mechanism for dynamic
CR-LSPs.
6.5 Licensing Requirements and Limitations for MPLS
TE
Involved Network Elements
Other network elements are not required.
License Requirements
MPLS TE is a basic feature of a switch and is not under license control.
Version Requirements
Table 6-25 Products and versions supporting MPLS TE
Produ
ct
Product
Model
Software Version
S1700
S1720GFR
Not supported
S1720GW,
S1720GWR
Not supported
S1720GW-E,
S1720GWR-E
Not supported
S1720X,
S1720X-E
Not supported
Other S1700
models
Models that cannot be configured using commands.
For details about features and versions, see S1700
Documentation Bookshelf.
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Produ
ct
Product
Model
Software Version
S2700
S2700SI
Not supported
S2700EI
Not supported
S2710SI
Not supported
S2720EI
Not supported
S2750EI
Not supported
S3700SI,
S3700EI
Not supported
S3700HI
Not supported
S5700LI
Not supported
S5700S-LI
Not supported
S5710-C-LI
Not supported
S5710-X-LI
Not supported
S5700SI
Not supported
S5700EI
Not supported
S5710EI
V200R002C00, V200R003C00, V200R005(C00&C02)
S5720EI
V200R009C00, V200R010C00, V200R011C00,
V200R011C10
S5720LI,
S5720S-LI
Not supported
S5720SI,
S5720S-SI
Not supported
S5700HI
V200R002C00, V200R003C00,
V200R005(C00SPC500&C01&C02)
S5710HI
V200R003C00, V200R005(C00&C02&C03)
S5720HI
V200R007C10, V200R009C00, V200R010C00,
V200R011C00, V200R011C10
S5730SI
Not supported
S5730S-EI
Not supported
S6720LI,
S6720S-LI
Not supported
S6720SI,
S6720S-SI
Not supported
S6700EI
V200R005(C00&C01&C02)
S3700
S5700
S6700
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Product
Model
Software Version
S6720EI
V200R008C00, V200R009C00, V200R010C00,
V200R011C00, V200R011C10
S6720S-EI
V200R009C00, V200R010C00, V200R011C00,
V200R011C10
To know details about software mappings, see Hardware Query Tool.
Feature Limitations
When configuring MPLS TE on the switch, pay attention to the following
points:
●
In V200R003 and earlier versions, only VLANIF interfaces support MPLS TE. In
V200R005 and later versions, both VLANIF interfaces and Layer 3 Ethernet
interfaces support MPLS TE.
●
On the S5720EI switch, if hardware support for MPLS is displayed as NO in
the output of the display device capability command, the switch does not
support MPLS. In this case, you need to pay attention to the following points:
–
MPLS cannot be enabled on the S5720EI switch. If the switch has been
added to a stack, MPLS cannot be enabled on the stack.
–
The S5720EI switch cannot be added to a stack running MPLS.
When configuring TE FRR on the switch, pay attention to the following
points:
●
Dynamic TE tunnels using bandwidth reserved in Shared Explicit (SE) style
support TE FRR, but static TE tunnels do not.
●
Except S5720HI, if TE FRR is enabled in a scenario where MPLS TE tunnels
transmit VPN services, you must configure PHP when the MP node is the
egress node of the primary CR-LSP.
●
In V200R005 and earlier versions, TE FRR can be performed during the RSVP
GR process. This protects traffic on the primary tunnel and speeds up
troubleshooting in the situation where a traffic switchover or a reboot is
triggered after a fault occurs on a PLR, the PLR's upstream node, an MP, or
the MP's downstream node, while the outbound interface of a primary tunnel
on the PLR fails. During the RSVP GR process, FRR switching is triggered if the
outbound interface of a primary tunnel on the PLR goes Down.
When configuring tunnel protection groups on the switch, pay attention to
the following points:
●
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A tunnel protection group works in either 1:1 or N:1 mode. The 1:1 mode
enables a protection tunnel to protect only one working tunnel. The N:1 mode
enables a protection tunnel to protect multiple working tunnels. In a tunnel
protection group, a maximum of 16 primary tunnels can be protected.
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●
Tunnel-specific attributes in a tunnel protection group are independent from
each other. For example, a protection tunnel with the bandwidth 50 Mbit/s
can protect a working tunnel with the bandwidth 100 Mbit/s.
●
Besides configuring a tunnel protection group to protect the working tunnel,
you can configure TE FRR on the working tunnel in the protection group for
dual protection to the working tunnel.
A tunnel protection group and TE FRR cannot be configured simultaneously on the
ingress node of a primary tunnel.
●
A protection tunnel cannot be protected by other tunnels or be enabled with
TE FRR.
When configuring BFD for MPLS TE on the switch, pay attention to the
following points:
●
BFD can detect faults in static and dynamic CR-LSPs.
●
BFD for LSP can function properly even if the forward and backward
forwarding modes are different. (For example, the forward path is an LSP and
the backward path is an IP link.) The forward path and the backward path
must be established over the same link; otherwise, if a fault occurs, BFD
cannot identify the faulty path. Before deploying BFD, ensure that the forward
and backward paths are over the same link so that BFD can correctly identify
the faulty path.
6.6 Default Settings for MPLS TE
Table 6-26 Default settings for MPLS TE
Parameter
Default Setting
MPLS TE
Disabled
RSVP TE
Disabled
Metric type in path selection for
tunnels
TE
Affinity property of tunnels
The values of affinity property and
mask are both 0x0.
Maximum reservable link bandwidth
0
Tunnel priority
The values of setup priority and hold
priority are both 7.
Route and label storing
Disabled
Route pinning
Disabled
Waiting period from a TE tunnel going
Down to the network informed of the
change
0
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6.7 Configuring a Static MPLS TE Tunnel
Configuring a static MPLS TE tunnel can implement setup of static CR-LSPs. The
configuration is simple. Labels are allocated manually and control packets do not
need to be exchanged, so static LSPs consume less resources.
Pre-configuration Tasks
Before configuring a static MPLS TE tunnel, complete the following tasks:
●
Configure an LSR ID on each LSR.
●
Enable basic MPLS functions on each LSR globally and on each interface.
After a static CR-LSP is bound to a tunnel interface, the static CR-LSP takes effect without
an IP route configured.
Configuration Procedure
Except that configuring link bandwidth is optional, all the other configurations are
mandatory.
6.7.1 Enabling MPLS TE
Context
Perform the following configurations on each node of the MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls te
MPLS TE is enabled on the node globally.
Step 4 Run quit
Return to the system view.
Step 5 Run interface interface-type interface-number
The view of the interface is displayed.
Step 6 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
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Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 7 Run mpls
The MPLS is enabled on the interface.
Step 8 Run mpls te
The MPLS TE is enabled on the interface.
----End
6.7.2 Configuring an MPLS TE Tunnel Interface
Context
Before setting up an MPLS TE Tunnel, you must create a tunnel interface and
configure other tunnel attributes on the tunnel interface. An MPLS TE tunnel
interface is responsible for establishing an MPLS TE tunnel and managing packet
forwarding on the tunnel.
Because the type of the packet forwarded by the MPLS TE tunnel is MPLS, the commands,
such as the ip verify source-address and urpf commands, related to IP packet forwarding
configured on this interface are invalid.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel interface-number
A tunnel interface is created and the tunnel interface view is displayed.
Step 3 To configure the IP address of the tunnel interface, select one of the following
commands.
●
Run ip address ip-address { mask | mask-length } [ sub ]
The IP address of the tunnel interface is configured.
The secondary IP address of the tunnel interface can be configured only after
the primary IP address is configured.
●
Or run ip address unnumbered interface interface-type interface-number
The tunnel interface is configured to borrow an IP address from other
interfaces.
An MPLS TE tunnel can be established even if the tunnel interface is assigned no
IP address. The tunnel interface must obtain an IP address before forwarding
traffic. An MPLS TE tunnel is unidirectional and does not need to configure a
separate IP address for the tunnel interface. Generally, a loopback interface is
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created on the ingress node and a 32-bit address that is the same as the LSR ID is
assigned to the loopback interface. Then the tunnel interface borrows the IP
address of the loopback interface.
Step 4 Run tunnel-protocol mpls te
MPLS TE is configured as a tunnel protocol.
Step 5 Run destination dest-ip-address
The destination address of the tunnel is configured, which is usually the LSR ID of
the egress node.
Different types of tunnels need different destination addresses. When the tunnel
protocol is changed to MPLS TE from other protocols, the configured destination
address is deleted automatically and you need to configure an address again.
Step 6 Run mpls te tunnel-id tunnel-id
The tunnel ID is configured.
Step 7 Run mpls te signal-protocol cr-static
The signal protocol of the tunnel is configured to be static CR-LSP.
Step 8 (Optional) Run mpls te signalled tunnel-name tunnel-name
The tunnel name is specified.
By default, the tunnel interface name such as Tunnel1 is used as the name of the
TE tunnel.
Step 9 Run mpls te commit
The current tunnel configuration is committed.
If MPLS TE parameters on a tunnel interface are modified, run the mpls te commit
command to activate them.
----End
6.7.3 (Optional) Configuring Link Bandwidth
Context
When a non-Huawei device as the ingress node of an MPLS TE tunnel initiates a
request for setting up a CR-LSP with bandwidth constraints, configure link
bandwidth on the connected Huawei device for negotiation so that the CR-LSP
can be set up and network resources are used efficiently.
The configured bandwidth takes effect only during tunnel establishment and protocol
negotiation, and does not limits the bandwidth for traffic forwarding. (S5720HI does not
have this restriction.)
Perform the following configurations on each node of the MPLS TE tunnel.
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Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface interface-type interface-number
The MPLS-TE-enabled interface view is displayed.
Step 3 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 4 Run mpls te bandwidth max-reservable-bandwidth bw-value
The maximum available bandwidth of the link is configured.
By default, the maximum reservable bandwidth of a link is 0 bit/s. The bandwidth
allocated to a static CR-LSP built over a link is certainly higher than 0 bit/s. If the
maximum reservable bandwidth of the link is not configured, the static CR-LSP
cannot be set up due to insufficient bandwidth.
Step 5 Run mpls te bandwidth { bc0 bc0-bw-value | bc1 bc1-bw-value }
*
The BC bandwidth of the link is configured.
●
The maximum reservable bandwidth of a link cannot be greater than the actual
bandwidth of the link. A maximum of 80% of the actual bandwidth of the link is
recommended for the maximum reservable bandwidth of the link.
●
Neither the BC0 bandwidth nor the BC1 bandwidth can be greater than the maximum
reservable bandwidth of the link.
----End
6.7.4 Configuring the Static CR-LSP
Context
When configuring a static MPLS TE tunnel, configure static CR-LSPs on the ingress,
transit, and egress nodes. When there is no intermediate node, there is no need to
configure a static CR-LSP on the intermediate node.
After static CR-LSPs are configured, you can execute commands again to modify CR-LSP
parameters.
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Procedure
●
Configure the ingress node.
Perform the following operations on the ingress node of a static MPLS TE
tunnel.
a.
Run system-view
The system view is displayed.
b.
Run static-cr-lsp ingress { tunnel-interface tunnel interface-number |
tunnel-name } destination destination-address { nexthop next-hopaddress | outgoing-interface interface-type interface-number } * outlabel out-label [ bandwidth [ ct0 | ct1 ] bandwidth ]
The static CR-LSP is configured on the ingress node.
tunnel interface-number specifies the MPLS TE tunnel interface that uses
this static CR-LSP. By default, the Bandwidth Constraints value is ct0, and
the value of bandwidth is 0. The bandwidth used by the tunnel cannot be
higher than the maximum reservable bandwidth of the link.
tunnel-name must be the same as the tunnel name created by using the
interface tunnel interface-number command. tunnel-name is a casesensitive character string in which spaces are not supported.
The next hop or outbound interface is determined by the route from the
ingress to the egress. For the difference between the next hop and
outbound interface, refer to Creating IPv4 Static Routes in "Static Route
Configuration" in the S1720, S2700, S5700, and S6720 V200R011C10
Configuration Guide - IP Unicast Routing.
If an Ethernet interface is used as an outbound interface of an LSP, the
nexthop next-hop-address parameter must be configured.
The configured bandwidth takes effect only during tunnel establishment and
protocol negotiation, and does not limits the bandwidth for traffic forwarding.
(S5720HI does not have this restriction.)
●
Configure a transit node.
Perform the following operations on the transit node of a static MPLS TE
tunnel.
a.
Run system-view
The system view is displayed.
b.
Run static-cr-lsp transit lsp-name [ incoming-interface interface-type
interface-number ] in-label in-label { nexthop next-hop-address |
outgoing-interface interface-type interface-number } * out-label outlabel [ bandwidth [ ct0 | ct1 ] bandwidth ] [ description description ]
The static CR-LSP is configured on the transit node.
lsp-name cannot be specified as the same as the name of an existing
tunnel on the node. The name of the MPLS TE tunnel interface associated
with the static CR-LSP can be used, such as Tunnel1.
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If an Ethernet interface is used as an outbound interface of an LSP, the
nexthop next-hop-address parameter must be configured.
The configured bandwidth takes effect only during tunnel establishment and
protocol negotiation, and does not limits the bandwidth for traffic forwarding.
(S5720HI does not have this restriction.)
●
Configure the egress node.
Perform the following operations on the egress node of a static MPLS TE
tunnel.
a.
Run system-view
The system view is displayed.
b.
Run static-cr-lsp egress lsp-name [ incoming-interface interface-type
interface-number ] in-label in-label
The static CR-LSP is configured on the egress node.
lsp-name cannot be specified as the same as the name of an existing
tunnel on the node. The name of the MPLS TE tunnel interface associated
with the static CR-LSP can be used, such as Tunnel1.
----End
6.7.5 Verifying the Configuration of a Static MPLS TE Tunnel
Prerequisites
The configurations of the static MPLS TE tunnel are complete.
Procedure
●
Run the display mpls static-cr-lsp [ lsp-name ] [ { include | exclude } ipaddress mask-length ] [ verbose ] command to check information about the
static CR-LSP.
●
Run the display mpls te tunnel [ destination ip-address ] [ lsp-id ingress-lsrid session-id local-lsp-id ] [ lsr-role { all | egress | ingress | remote |
transit } ] [ name tunnel-name ] [ { incoming-interface | interface |
outgoing-interface } interface-type interface-number ] [ verbose ] command
to check tunnel information.
●
Run the display mpls te tunnel statistics or display mpls lsp statistics
command to check tunnel statistics.
●
Run the display mpls te tunnel-interface [ tunnel interface-number ]
command to check information about the tunnel interface on the ingress
node.
----End
6.8 Configuring a Dynamic MPLS TE Tunnel
Dynamic MPLS TE tunnels are set up using RSVP-TE signaling and are changed
according to network changes. On a large-scale network, dynamic MPLS TE
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tunnels reduce the burden of per-hop configuration. Configuring a dynamic MPLS
TE tunnel is the basis for configuring advanced features of MPLS TE.
Pre-configuration Tasks
Before configuring a dynamic MPLS TE tunnel, complete the following tasks:
●
Configure an IGP to ensure reachable routes between nodes.
●
Configure an LSR ID for each node.
●
Enable MPLS globally on each node.
●
Enable MPLS on each interface of each node.
Configuration Procedure
Except that configuring link bandwidth, referencing the CR-LSP attribute template
to set up a CR-LSP, and configuring tunnel constraints are optional, all the other
configurations are mandatory.
6.8.1 Enabling MPLS TE and RSVP-TE
Context
To create a dynamic MPLS TE tunnel, first enable MPLS TE, enable RSVP-TE
globally, enable RSVP-TE on an interface, and perform other configurations, such
as setting the link bandwidth attributes and enabling CSPF.
Perform the following configurations on each node of the MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls te
MPLS TE is enabled on the node globally.
Step 4 Run mpls rsvp-te
RSVP-TE is enabled on the node.
Step 5 Run quit
The system view is displayed.
Step 6 Run interface interface-type interface-number
The MPLS TE interface view is displayed.
Step 7 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
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By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 8 Run mpls
The MPLS is enabled on the interface.
Step 9 Run mpls te
The MPLS TE is enabled on the interface.
Step 10 Run mpls rsvp-te
RSVP-TE is enabled on the interface.
----End
6.8.2 Configuring an MPLS TE Tunnel Interface
Context
A tunnel interface must be created on the ingress so that a tunnel can be
established and forward data packets.
A tunnel interface supports the following functions:
●
Establishes a tunnel. Tunnel constraints, bandwidth attributes, and advanced
attributes such as TE FRR and tunnel re-optimization can be configured on
the tunnel interface to establish the tunnel.
●
Manages a tunnel. Tunnel attributes can be modified on the tunnel interface
to manage the tunnel.
Because MPLS TE tunnels forward MPLS packets, not IP packets, IP forwarding-related
commands run on the tunnel interface are invalid.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel interface-number
A tunnel interface is created and the tunnel interface view is displayed.
NOTICE
If the shutdown command is run on the tunnel interface, all tunnels established
on the tunnel interface will be deleted.
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Step 3 Run either of the following commands to assign an IP address to the tunnel
interface:
●
To configure an IP address for the tunnel interface, run ip address ip-address
{ mask | mask-length } [ sub ]
The primary IP address must be configured before the secondary IP address is
configured.
●
To configure the tunnel interface to borrow an IP address of another
interface, run ip address unnumbered interface interface-type interface-
number
An MPLS TE tunnel can be established even if the tunnel interface is assigned no
IP address. The tunnel interface must obtain an IP address before forwarding
traffic. An MPLS TE tunnel is unidirectional and does not need to configure a
separate IP address for the tunnel interface. Generally, a loopback interface is
created on the ingress node and a 32-bit address that is the same as the LSR ID is
assigned to the loopback interface. Then the tunnel interface borrows the IP
address of the loopback interface.
Step 4 Run tunnel-protocol mpls te
MPLS TE is configured as a tunnel protocol.
Step 5 Run destination dest-ip-address
A tunnel destination address is configured, which is usually the LSR ID of the
egress.
Various types of tunnels require specific destination addresses. If a tunnel protocol
is changed from another protocol to MPLS TE, a configured destination address is
deleted automatically and a new destination address needs to be configured.
Step 6 Run mpls te tunnel-id tunnel-id
A tunnel ID is set.
Step 7 Run mpls te signal-protocol rsvp-te
RSVP-TE is configured as the signaling protocol.
Step 8 (Optional) Run mpls te signalled tunnel-name tunnel-name
The tunnel name is specified.
By default, the tunnel interface name such as Tunnel1 is used as the name of the
TE tunnel.
Perform this step to fulfill the following purposes:
●
Facilitate TE tunnel management.
●
Allow a Huawei device to be connected to a non-Huawei device that uses a
tunnel name that differs from the tunnel interface name.
Step 9 (Optional) Run mpls te cspf disable
Do not perform the constraint shortest path first (CSPF) calculation when an
MPLS TE tunnel is being set up.
Step 10 Run mpls te commit
The configuration is committed.
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The mpls te commit command must be run to make configurations take effect each time
MPLS TE parameters are changed on a tunnel interface.
----End
6.8.3 (Optional) Configuring Link Bandwidth
Context
When a non-Huawei device as the ingress node of an MPLS TE tunnel initiates a
request for setting up a CR-LSP with bandwidth constraints, configure link
bandwidth on the connected Huawei device for negotiation so that the CR-LSP
can be set up and network resources are used efficiently.
The configured bandwidth takes effect only during tunnel establishment and protocol
negotiation, and does not limits the bandwidth for traffic forwarding. (S5720HI does not
have this restriction.)
Perform the following configurations on each node of the MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface interface-type interface-number
The MPLS-TE-enabled interface view is displayed.
Step 3 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 4 Run mpls te bandwidth max-reservable-bandwidth bw-value
The maximum available bandwidth of the link is configured.
By default, the maximum reservable bandwidth of a link is 0 bit/s. The bandwidth
allocated to a static CR-LSP built over a link is certainly higher than 0 bit/s. If the
maximum reservable bandwidth of the link is not configured, the static CR-LSP
cannot be set up due to insufficient bandwidth.
Step 5 Run mpls te bandwidth { bc0 bc0-bw-value | bc1 bc1-bw-value }
*
The BC bandwidth of the link is configured.
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●
The maximum reservable bandwidth of a link cannot be greater than the actual
bandwidth of the link. A maximum of 80% of the actual bandwidth of the link is
recommended for the maximum reservable bandwidth of the link.
●
Neither the BC0 bandwidth nor the BC1 bandwidth can be greater than the maximum
reservable bandwidth of the link.
----End
6.8.4 Advertising TE Link Information
Context
Nodes on an MPLS network use OSPF TE to exchange TE link attributes such as
bandwidth and colors to generate TEDBs. TEDB information is used by CSPF to
calculate paths for MPLS TE tunnels. Current, the device can use two methods to
advertise TE information to generate TEDBs.
●
OSPF TE
OSPF TE is an OSPF extension used on an MPLS TE network. LSRs on the
MPLS area exchange Opaque Type 10 LSAs that carry TE link information to
generate TEDBs for CSPF calculation.
OSPF areas do not support TE by default. The OSPF Opaque capability must
be enabled to support OSPF TE, and a node can generate Opaque Type 10
LSAs only if at least one OSPF neighbor is in the Full state.
If OSPF TE is disabled, no Opaque Type 10 LSA is generated or exchanged by nodes to
generate TEDBs. On an OSPF TE-incapable network, CR-LSPs are established using
OSPF routes but not CSPF calculation results.
●
IS-IS TE
IS-IS TE is an IS-IS extension used on an MPLS TE network. IS-IS TE defines a
new TLV in Link State Packets (LSPs) and IS-IS TE-enabled nodes send these
LSPs to flood and synchronize TE link information. IS-IS TE extracts TE link
information from LSPs and then transmits the TE link information to the CSPF
module for calculating tunnel paths.
Use the mode in which TE information is advertised according to the IGP used on
the backbone network. Perform the following operations on each node of an
MPLS TE tunnel.
Procedure
●
Configure OSPF TE.
a.
Run system-view
The system view is displayed.
b.
Run ospf [ process-id ]
The OSPF view is displayed.
c.
Run opaque-capability enable
The OSPF Opaque capability is enabled.
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d.
6 MPLS TE Configuration
(Optional) Run advertise mpls-lsr-id
The node is enabled to advertise an MPLS LSR ID to multiple OSPF areas.
This step is performed only on an area border router (ABR) connected to multiple
OSPF areas.
e.
Run area area-id
The OSPF area view is displayed.
f.
Run mpls-te enable [ standard-complying ]
MPLS TE is enabled in the OSPF area.
●
Configure IS-IS TE.
a.
Run system-view
The system view is displayed.
b.
Run isis [ process-id ]
The IS-IS view is displayed.
c.
Run cost-style { compatible [ relax-spf-limit ] | wide | widecompatible }
The IS-IS wide metric function is enabled.
IS-IS TE uses sub-TLVs of the IS reachability TLV (type 22) to carry TE link
information. The IS-IS wide metric must be configured to support the IS
reachability TLV. The IS-IS wide metric supports the wide, compatible, and
wide-compatible metric types. By default, IS-IS sends and receives LSPs
with narrow metric values.
d.
Run traffic-eng [ level-1 | level-2 | level-1-2 ]
IS-IS TE is enabled.
By default, TE is not enabled for IS-IS processes.
If no IS-IS level is specified, the node is a Level-1-2 device that can
generate two TEDBs for communicating with Level-1 and Level-2 devices.
----End
6.8.5 (Optional) Referencing the CR-LSP Attribute Template
to Set Up a CR-LSP
Context
You can create a CR-LSP by using the following methods:
●
Creating a CR-LSP without using a CR-LSP attribute template
●
Creating a CR-LSP by using a CR-LSP attribute template
It is recommended to use a CR-LSP attribute template to set up a CR-LSP
because this method has the following advantages:
–
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CR-LSPs.
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–
A maximum of three CR-LSP attribute templates can be created for a hotstandby CR-LSP or an ordinary backup CR-LSP. You can set up a hotstandby CR-LSP or an ordinary backup CR-LSP with different path
options. (Among the three attribute templates, the template with the
smallest sequence number is first used. If the setup fails, the template
with a greater sequence number is used.)
–
If configurations of a CR-LSP attribute template are modified,
configurations of the CR-LSPs established by using the CR-LSP attribute
template are automatically updated, which makes the configurations of
CR-LSPs more flexible.
The preceding two methods can be used together. If the TE attribute configured in the
tunnel interface view and the TE attribute configured through a CR-LSP attribute template
coexist, the former takes precedence over the latter.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
1.
Configuring a CR-LSP Attribute Template
Steps 3 to 10 are optional. You can perform one or more of them as required.
2.
Setting Up a CR-LSP by Using a CR-LSP Attribute Template
You can use a CR-LSP attribute template to set up the primary CR-LSP, hotstandby CR-LSP, and ordinary backup CR-LSP.
Procedure
●
Configure a CR-LSP attribute template.
a.
Run system-view
The system view is displayed.
b.
Run lsp-attribute lsp-attribute-name
A CR-LSP attribute template is created and the LSP attribute view is
displayed.
NOTICE
A CR-LSP attribute template can be deleted only when it is not used by
any tunnel interface.
c.
(Optional) Run bandwidth { ct0 ct0-bandwidth | ct1 ct1-bandwidth }
The bandwidth is set for the CR-LSP attribute template.
Perform this step to provide bandwidth protection for services
transmitted on a TE tunnel established using this template.
d.
(Optional) Run explicit-path path-name
An explicit path is configured for the CR-LSP attribute template.
Perform this step to control the path over which a TE tunnel is
established.
e.
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(Optional) Run affinity property affinity-value [ mask mask-value ]
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The affinity attribute is set for the CR-LSP attribute template.
By default, both the affinity value and the affinity mask are 0x0.
This step helps you control the path over which a TE tunnel is established.
f.
(Optional) Run priority setup_priority_value [ hold_priority_value ]
The setup priority and hold priority are set for the CR-LSP attribute
template.
By default, both the setup priority and the hold priority are 7.
If resources are insufficient, setting the setup and hold priority values
helps a device release resources used by LSPs with lower priorities and
use the released resources to establish LSPs with higher priorities.
g.
(Optional) Run hop-limit hop-limit
The hop limit is set for the CR-LSP attribute template.
By default, the hop limit is 32.
h.
(Optional) Run fast-reroute [ bandwidth ]
FRR is enabled for the CR-LSP attribute template.
By default, FRR is disabled.
FRR is recommended for networks requiring high reliability.
Before enabling or disabling FRR for the CR-LSP attribute template, note the
following:
● After FRR is enabled, the system automatically records routes for the CR-LSP.
● After FRR is disabled, attributes of the bypass tunnel are automatically
deleted.
● The undo mpls te record-route command can take effect only when FRR is
disabled.
i.
(Optional) Run record-route [ label ]
The system is configured to record routes for the CR-LSP attribute
template.
By default, the system does not record routes for the CR-LSP attribute
template.
Perform this step to view label information and the number of hops on a
path over which a TE tunnel is established.
j.
(Optional) Run bypass-attributes { bandwidth bandwidth | priority
setup_priority_value [ hold_priority_value ] }*
The bypass tunnel attributes are configured for the CR-LSP attribute
template.
By default, the bypass tunnel attributes are not configured.
k.
Run commit
Configurations of the CR-LSP attribute template are committed.
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When the CR-LSP attribute template is used to set up a CR-LSP:
●
n
The CR-LSP is removed and a new CR-LSP is created if the BreakBefore-Make attribute (the priority attribute) of the CR-LSP attribute
template is modified.
n
The CR-LSP is removed after an eligible CR-LSP is created and traffic
switches to the new CR-LSP if the Make-Before-Break attribute of the
CR-LSP attribute template is modified.
Set up a CR-LSP by using a CR-LSP attribute template.
a.
Run system-view
The system view is displayed.
b.
Run interface tunnel interface-number
The tunnel interface view is displayed.
c.
Run mpls te primary-lsp-constraint { dynamic | lsp-attribute lspattribute-name }
The primary CR-LSP is set up through the specified CR-LSP attribute
template.
If dynamic is used, it indicates that when a CR-LSP attribute template is
used to set up a primary CR-LSP, all attributes in the template use the
default values.
d.
(Optional) Run mpls te hotstandby-lsp-constraint number { dynamic |
lsp-attribute lsp-attribute-name }
The hot-standby CR-LSP is set up by using the specified CR-LSP attribute
template.
A maximum of three CR-LSP attribute templates can be used to set up a
hot-standby CR-LSP. The hot-standby CR-LSP must be consistent with the
primary CR-LSP in the attributes of the setup priority, hold priority, and
bandwidth type. To set up a hot-standby CR-LSP, you should keep on
attempting to use CR-LSP attribute templates one by one in ascending
order of the number of the attribute templates until the hot-standby CRLSP is set up.
If dynamic is used, it indicates that the hot-standby CR-LSP is assigned
the same bandwidth and priority as the primary CR-LSP, but specified
with a different path from the primary CR-LSP.
e.
(Optional) Run mpls te backup hotstandby-lsp-constraint wtr interval
The Wait to Restore (WTR) time is set for the traffic to switch back from
the hot-standby CR-LSP to the primary CR-LSP.
By default, the WTR time for the traffic to switch back from the hotstandby CR-LSP to the primary CR-LSP is 10 seconds.
The hot-standby CR-LSP specified in the mpls te backup hotstandby-lspconstraint wtr command must be an existing one established by running the
mpls te hotstandby-lsp-constraint command.
f.
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(Optional) Run mpls te ordinary-lsp-constraint number { dynamic | lspattribute lsp-attribute-name }
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The ordinary backup CR-LSP is set up by using the specified CR-LSP
attribute template.
A maximum of three CR-LSP attribute templates can be used to set up an
ordinary backup CR-LSP. The ordinary backup CR-LSP must be consistent
with the primary CR-LSP in the attributes of the setup priority, hold
priority, and bandwidth type. To set up an ordinary backup CR-LSP, you
should keep on attempting to use CR-LSP attribute templates one by one
in ascending order of the number of the attribute template until the
ordinary backup CR-LSP is set up.
If dynamic is used, it indicates that the ordinary backup CR-LSP is
assigned the same bandwidth and priority as the primary CR-LSP.
g.
(Optional) Run mpls te backup ordinary-lsp-constraint lock
The attribute template of the ordinary backup CR-LSP is locked.
By default, the attribute template of the ordinary backup CR-LSP is not
locked.
Before running this command, you must run the mpls te ordinary-lsp-constraint
command to reference the CR-LSP attribute template to set up an ordinary
backup CR-LSP.
h.
Run mpls te commit
The configurations of the CR-LSP are committed.
----End
6.8.6 (Optional) Configuring Tunnel Constraints
Context
Constraints such as bandwidth and explicit path attributes can be configured on
the ingress to accurately and flexibly establish an RSVP-TE tunnel.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
1.
Configuring an MPLS TE Explicit Path
You need to configure an explicit path before you can configure constraints on
the explicit path.
An explicit path refers to a vector path on which a series of nodes are
arranged in configuration sequence. The IP address of an interface on the
egress is usually used as the destination address of the explicit path. Links or
nodes can be specified for an explicit path so that a CR-LSP can be established
over the specified path, facilitating resource allocation and efficiently
controlling CR-LSP establishment.
Two adjacent nodes are connected in either of the following modes on an
explicit path:
–
Strict: Two consecutive hops must be directly connected. This mode
strictly controls the path through which the LSP passes.
–
Loose: Other nodes may exist between a hop and its next hop.
The strict and loose modes are used either separately or together.
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6 MPLS TE Configuration
Configuring Tunnel Constraints
After constraints are configured for tunnel establishment, a CR-LSP is
established over a path calculated by CSPF.
Procedure
●
Configure an MPLS TE explicit path.
a.
Run system-view
The system view is displayed.
b.
Run explicit-path path-name
An explicit path is created and the explicit path view is displayed.
c.
Run next hop ip-address [ include [ [ loose | strict ] | [ incoming |
outgoing ] ] * | exclude ]
A next-hop address is specified for the explicit path.
By default, the include strict parameters are configured, meaning that a
hop and its next hop must be directly connected. An explicit path can be
configured to pass through a specified node or not to pass through a
specified node.
Either of the following parameters can be configured:
d.
n
incoming: sets the ip-address to the IP address of an inbound
interface of a next-hop node.
n
outgoing: sets the ip-address to the IP address of an outbound
interface of a next-hop node.
You can run the following commands to add, modify, or delete nodes on
the explicit path.
n
Run list hop [ ip-address ]
Information about nodes on the explicit path is displayed.
n
Run add hop ip-address1 [ include [ [ loose | strict ] | [ incoming |
outgoing ] ] * | exclude ] { after | before } ip-address2
A node is added to the explicit path.
By default, the include strict parameters are configured, meaning
that a hop and its next hop must be directly connected. An explicit
path can be configured to pass through a specified node or not to
pass through a specified node.
Either of the following parameters can be configured:
n
○
incoming: sets the ip-address1 to the IP address of an inbound
interface of a new-added node.
○
outgoing: sets the ip-address1 to the IP address of an outbound
interface of a new-added node.
Run modify hop ip-address1 ip-address2 [ include [ [ loose | strict ]
| [ incoming | outgoing ] ] * | exclude ]
The address of a node is changed to allow another specified node to
be used by the explicit path.
By default, the include strict parameters are configured, meaning
that a hop and its next hop must be directly connected. An explicit
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path can be configured to pass through a specified node or not to
pass through a specified node.
Either of the following parameters can be configured:
n
○
incoming: sets the ip-address2 to the IP address of an inbound
interface of the modified node.
○
outgoing: sets the ip-address2 to the IP address of an outbound
interface of the modified node.
Run delete hop ip-address
A node is deleted from the explicit path.
●
Configure tunnel constraints.
a.
Run system-view
The system view is displayed.
b.
Run interface tunnel tunnel-number
The tunnel interface view is displayed.
c.
Run mpls te bandwidth { ct0 ct0-bw-value | ct1 ct1-bw-value }
The bandwidth is configured for the tunnel.
The bandwidth used by the tunnel cannot be greater than the maximum
reservable link bandwidth.
Ignore this step if only an explicit path is required.
The configured bandwidth takes effect only during tunnel establishment and
protocol negotiation, and does not limits the bandwidth for traffic forwarding.
(S5720HI does not have this restriction.)
d.
Run mpls te path explicit-path path-name
An explicit path is configured for the tunnel.
Ignore this step if only the bandwidth needs to be specified.
e.
Run mpls te commit
The configuration is committed.
----End
6.8.7 Configuring Path Calculation
Context
To calculate a tunnel path meeting specified constraints, CSPF should be
configured on the ingress.
CSPF extends the shortest path first (SPF) algorithm and is able to calculate the
shortest path meeting MPLS TE requirements. CSPF calculates paths using the
following information:
●
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●
Network resource attributes, such as the maximum available bandwidth,
maximum reservable bandwidth, and affinity property, sent by IGP-TE and
saved in TEDBs
●
Configured constraints such as explicit paths
● An RSVP-TE tunnel can be established on a CSPF-disabled ingress. However, to allow a
path to meet tunnel constraints, you are advised to enable CSPF on the ingress before
establishing the RSVP-TE tunnel.
● Enabling CSPF on all transit nodes is recommended. The tunnel function fails if CSPF or
IGP TE is not enabled on the ingress, IGP TE is not enabled on some transit nodes or the
egress, and CSPF is enabled on some transit nodes.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls te cspf
CSPF is enabled on a node.
CSPF is disabled by default.
Step 4 (Optional) Run mpls te cspf preferred-igp { isis [ isis-process-id [ level-1 |
level-2 ] ] | ospf [ ospf-process-id [ area { area-id-1 | area-id-2 } ] ] }
A preferred IGP is specified.
By default, OSPF is preferred for CSPF path calculation.
If a single IGP protocol is only configured on the backbone network to advertise
OSPF or IS-IS TE information, ignore this step.
----End
6.8.8 Verifying the Configuration of a Dynamic MPLS TE
Tunnel
Prerequisites
The configurations of a dynamic MPLS TE tunnel are complete.
Procedure
●
Run the display mpls te link-administration bandwidth-allocation
[ interface interface-type interface-number ] command to check information
about the allocated link bandwidth.
●
Run the display ospf [ process-id ] mpls-te [ area area-id ] [ selforiginated ] command to check information about OSPF TE.
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●
6 MPLS TE Configuration
Run one of the following commands to check IS-IS TE information:
–
display isis traffic-eng advertisements
–
display isis traffic-eng link
–
display isis traffic-eng network
–
display isis traffic-eng statistics
–
display isis traffic-eng sub-tlvs
●
Run the display explicit-path [ [ name ] path-name ] [ tunnel-interface |
lsp-attribute | verbose ] command to check configured explicit paths.
●
Run the display mpls te cspf destination ip-address [ affinity properties
[ mask mask-value ] | bandwidth { ct0 ct0-bandwidth | ct1 ct1-bandwidth } *
| explicit-path path-name | hop-limit hop-limit-number | metric-type { igp |
te } | priority setup-priority | srlg-strict exclude-path-name | tie-breaking
{ random | most-fill | least-fill } ] * [ hot-standby [ explicit-path path-name
| overlap-path | affinity properties [ mask mask-value ] | hop-limit hoplimit-number | srlg { preferred | strict } ] * ] command to check information
about a path that is calculated using CSPF based on specified conditions.
●
Run the display mpls te cspf tedb { all | area { area-id | area-id-ip } |
interface ip-address | network-lsa | node [ router-id ] | srlg srlg-number |
overload-node } command to check information about TEDBs that can meet
specified conditions and be used by CSPF to calculate paths.
●
Run the display mpls rsvp-te command to check RSVP information.
●
Run the display mpls rsvp-te established [ interface interface-type
interface-number peer-ip-address ] command to check information about the
established RSVP-TE CR-LSPs.
●
Run the display mpls rsvp-te peer [ interface interface-type interfacenumber ] command to check RSVP neighbor parameters.
●
Run the display mpls rsvp-te reservation [ interface interface-type
interface-number peer-ip-address ] command to check information about
RSVP resource reservation.
●
Run the display mpls rsvp-te request [ interface interface-type interfacenumber peer-ip-address ] command to check information about the RSVP-TE
request messages on interfaces.
●
Run the display mpls rsvp-te sender [ interface interface-type interfacenumber peer-ip-address ] command to check information about RSVP
senders.
●
Run the display mpls rsvp-te statistics { global | interface [ interface-type
interface-number ] } command to check RSVP-TE statistics.
●
Run the display mpls te link-administration admission-control [ interface
interface-type interface-number | stale-interface interface-index ] command
to check the tunnels set up on the local node.
●
Run the display mpls te tunnel [ destination ip-address ] [ lsp-id ingress-lsrid session-id local-lsp-id ] [ lsr-role { all | egress | ingress | remote |
transit } ] [ name tunnel-name ] [ { incoming-interface | interface |
outgoing-interface } interface-type interface-number ] [ verbose ] command
to check tunnel information.
●
Run the display mpls te tunnel statistics or display mpls lsp statistics
command to check tunnel statistics.
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●
Run the display lsp-attribute [ name lsp-attribute-name ] [ tunnelinterface | verbose ] command to check the configurations of the CR-LSP
attribute template and the tunnels using it.
●
Run the display mpls te tunnel-interface lsp-constraint [ tunnel interfacenumber ] command to view information about the CR-LSP attribute template
on the TE tunnel interface.
●
Run the display mpls te tunnel-interface [ tunnel interface-number | autobypass-tunnel [ tunnel-name ] ] command to check information about the
MPLS TE tunnel.
●
Run the display mpls te tunnel c-hop [ tunnel-name ] [ lsp-id ingress-lsr-id
session-id lsp-id ] command to check path computation results of tunnels.
●
Run the display mpls te session-entry [ ingress-lsr-id tunnel-id egress-lsr-id ]
command to check detailed information about the LSP session entry.
----End
6.9 Importing Traffic to an MPLS TE Tunnel
An MPLS TE tunnel does not automatically direct traffic. To enable traffic to travel
along an MPLS TE tunnel, you need to use some method to direct traffic to the
MPLS TE tunnel.
Pre-configuration Tasks
Before importing traffic to the MPLS TE tunnel, complete one of the following
tasks:
●
Configure a static MPLS TE tunnel. For details, see 6.7 Configuring a Static
MPLS TE Tunnel.
●
Configure a dynamic MPLS TE tunnel. For details, see 6.8 Configuring a
Dynamic MPLS TE Tunnel.
Configuration Procedure
To direct traffic to the MPLS TE tunnel, perform one of the following operations
according to the network planning. You are advised to use the auto route
mechanism.
6.9.1 Configuring Static Routes
Context
Using static routes is the simplest method for importing traffic to an MPLS TE
tunnel.
Procedure
Static routes in an MPLS TE tunnel are similar to common static routes. You only
need to configure a static route with a TE tunnel interface as the outbound
interface. For detailed instructions, see Configuring IPv4 Static Routes in "Static
Route Configuration" in the S1720, S2700, S5700, and S6720 V200R011C10
Configuration Guide - IP Unicast Routing.
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6.9.2 Configuring a Tunnel Policy
Context
In general, VPN traffic is forwarded through an LSP tunnel but not an MPLS TE
tunnel. To import VPN traffic to the MPLS TE tunnel, you need to configure a
tunnel policy.
Procedure
You can configure either of the following types of tunnel policies according to
service requirements:
●
Tunnel type prioritizing policy: Such a policy specifies the sequence in which
different types of tunnels are selected by the VPN. For example, you can
specify the VPN to select the TE tunnel first.
●
Tunnel binding policy: This policy binds a TE tunnel to a specified VPN by
binding a specified destination address to the TE tunnel to provide QoS
guarantee.
For detailed instructions, see Configuring and Applying a Tunnel Policy in "BGP/
MPLS IP VPN Configuration" in the S1720, S2700, S5700, and S6720 V200R011C10
Configuration Guide - VPN.
6.9.3 Configuring Auto Routes
Context
After you configure auto routes, TE tunnels act as logical links to participate in IGP
route calculation and tunnel interfaces are used as the outbound interfaces of
packets. Devices on network nodes determine whether to advertise LSP
information to neighboring nodes to instruct packet forwarding. Two modes are
available for auto routes:
●
Configuring IGP shortcut: A device uses a TE tunnel for local route
calculation and does not advertise the TE tunnel to its peers as a route.
Therefore, the peers of this device cannot use the TE tunnel for route
calculation.
●
Configuring forwarding adjacency: A device uses a TE tunnel for local route
calculation and advertises the TE tunnel to its peers as a route. Therefore, the
peers of this device can use the TE tunnel for route calculation.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
● IGP shortcut and forwarding adjacency are exclusive to each other.
● When using forwarding adjacency to advertise LSP information to other nodes for
bidirectional detection on links, you must configure another tunnel for transmitting
packets in the opposite direction, and then enable forwarding adjacency on the two
tunnels.
Procedure
●
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Configuring IGP Shortcut
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a.
6 MPLS TE Configuration
Run system-view
The system view is displayed.
b.
Run interface tunnel interface-number
The interface view of the MPLS TE tunnel is displayed.
c.
Run mpls te igp shortcut [ isis | ospf ]
The IGP shortcut is configured.
By default, the IGP shortcut is not configured. If the IGP type is not
specified when the IGP shortcut is configured, both IS-IS and OSPF are
supported by default.
d.
Run mpls te igp metric { absolute absolute-value | relative relativevalue }
The IGP metric value for the tunnel is configured.
By default, the metric value used by the TE tunnel is the same as that of
the IGP.
You can specify a metric value used by the TE tunnel when path is
calculated in the IGP shortcut feature.
e.
n
If the absolute metric is used, the TE tunnel is equal to the
configured metric value.
n
If the relative metric is used, the TE tunnel is equal to the sum of
the metric value of the corresponding IGP path and relative metric
value.
Run mpls te commit
The current TE tunnel configuration is committed.
f.
You can select either of the following modes to configure IGP shortcut.
n
For IS-IS, run isis enable [ process-id ]
IS-IS is enabled on the tunnel interface.
n
●
For OSPF, run the following commands in sequence:
1)
Run the quit command to return to the system view.
2)
Run the ospf [ process-id ] command to enter the OSPF view.
3)
Run the enable traffic-adjustment command to enable IGP
shortcut function.
Configuring Forwarding Adjacency
a.
Run system-view
The system view is displayed.
b.
Run interface tunnel interface-number
The tunnel interface view is displayed.
c.
Run mpls te igp advertise [ hold-time interval ]
The forwarding adjacency is enabled.
d.
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Run mpls te igp metric { absolute absolute-value | relative relativevalue }
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The IGP metric value for the tunnel is configured.
The IGP metric value must be set properly to ensure that LSP information is
advertised and used correctly. For example, the metric of a TE tunnel must be
less than that of IGP routes to ensure that the TE tunnel is used as a route link.
If relative is configured and IS-IS is used as an IGP, this step cannot modify the
IS-IS metric value. To change the IS-IS metric value, configure absolute in this
step.
e.
Run mpls te commit
The current tunnel configuration is committed.
f.
You can select either of the following modes to enable the forwarding
adjacency.
n
For IS-IS, run isis enable [ process-id ]
IS-IS is enabled on the tunnel interface.
n
For OSPF, run the following commands in sequence:
1)
Run quit
The system view is displayed.
2)
Run ospf [ process-id ]
The OSPF view is displayed.
3)
Run enable traffic-adjustment advertise
Forwarding adjacency is enabled.
----End
6.9.4 Verifying the Configuration of Importing Traffic to an
MPLS TE Tunnel
Prerequisites
The configuration for importing traffic to an MPLS TE tunnel is complete.
Procedure
●
Run the display current-configuration command to view the configuration
for importing traffic to an MPLS TE tunnel.
●
Run the display ip routing-table command to view the routes with an MPLS
TE tunnel interface as the outbound interface.
●
Run the display ospf [ process-id ] traffic-adjustment command to check
tunnel information about OSPF processes related to traffic adjustment (IGP
shortcut and forwarding adjacency).
----End
6.10 Adjusting RSVP-TE Signaling Parameters
RSVP-TE provides various signaling parameters, which meet the requirements for
reliability and network resources.
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Pre-configuration Tasks
Before adjusting RSVP-TE signaling parameters, complete the following task:
●
Configure a dynamic MPLS TE tunnel. For details, see 6.8 Configuring a
Dynamic MPLS TE Tunnel.
Configuration Procedure
The following configurations are optional and can be performed in any sequence.
6.10.1 Configuring an RSVP Resource Reservation Style
Context
If multiple CR-LSPs pass through the same node, the ingress nodes can be
configured with an RSVP resource reservation style to allow the CR-LSPs to share
reserved resources or use separate reserved resources on the overlapping node.
A reservation style is used by an RSVP node to reserve resources after receiving
resource reservation requests from upstream nodes. The device supports the
following reservation styles:
●
Fixed filter (FF): creates an exclusive reservation for each sender. A sender
does not share its resource reservation with other senders, and each CR-LSP
on a link has a separate resource reservation.
●
SE: creates a single reservation for a series of selected upstream senders. CRLSPs on a link share the same resource reservation.
The SE style is used for tunnels established using the Make-Before-Break
mechanism, whereas the FF style is seldom used.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel tunnel-number
The tunnel interface view is displayed.
Step 3 Run mpls te resv-style { ff | se }
A resource reservation style is configured.
The default resource reservation style is SE.
Step 4 Run mpls te commit
The configuration is committed.
----End
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6.10.2 Enabling Reservation Confirmation Mechanism
Context
Receiving an ResvConf message does not mean that the resource reservation
succeeds. It means that resources are reserved successfully only on the farthest
upstream node where this Resv message arrives. These resources, however, may be
preempted by other applications later. You can enable reservation confirmation
mechanism to prevent this problem.
Perform the following configurations on the egress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls rsvp-te resvconfirm
The reservation confirmation mechanism is enabled.
The reservation confirmation is initiated by the receiver of Path message. An
object that requires confirming the reservation is carried along the Resv message
sent by the receiver.
----End
6.10.3 Configuring RSVP Timers
Context
If an RSVP node does not receive any Refresh message within a specified period, it
deletes the path or reservation state. You can set the interval for sending Path/
Resv messages and retry count by setting RSVP timers to change the timeout
interval. The default interval and retry count are recommended. The timeout
interval is calculated using the following formula:
Timeout interval = (keep-multiplier-number + 0.5) x 1.5 x refresh-interval.
In the formula, keep-multiplier-number specifies the retry count allowed for RSVP
Refresh messages; refresh-interval specifies the interval for sending RSVP Refresh
messages.
Perform the following configurations on each node of the MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
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Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls rsvp-te timer refresh refresh-interval
The interval for sending RSVP Refresh messages is set.
By default, the interval for sending RSVP Refresh messages is 30 seconds.
If the interval is modified, the modification takes effect after the timer expires.
You are not advised to set a long interval or modify the interval frequently.
Step 4 Run mpls rsvp-te keep-multiplier keep-multiplier-number
The retry count allowed for RSVP Refresh messages is configured.
By default, the retry count allowed for RSVP Refresh messages is 3.
----End
6.10.4 Configuring RSVP-TE Refresh Mechanism
Context
Enabling Srefresh in the mpls view on two nodes that are the neighbors of each
other can reduce the cost and improve the performance of a network. In the MPLS
view, Srefresh can be enabled on the entire device. After Srefresh is enabled, the
retransmission of Srefresh messages is automatically enabled on the interface or
the device.
The Srefresh mechanism in MPLS view is applied to the TE FRR networking. Srefresh is enabled
globally on the Point of Local Repair (PLR) and Merge Point (MP) over an FRR bypass tunnel.
This allows efficient use of network resources and improves Srefresh reliability.
Assume that a node initializes the retransmission interval as Rf seconds. If
receiving no ACK message within Rf seconds, the node retransmits the RSVP
message after (1 + Delta) x Rf seconds. The value of Delta depends on the link
rate. The node retransmits the message until it receives an ACK message or the
times of retransmission reach the threshold (that is, retransmission increment
value).
Perform the following configurations on each node of the MPLS TE tunnel.
Procedure
●
Perform the following steps in the MPLS view.
a.
Run system-view
The system view is displayed.
b.
Run mpls
The MPLS view is displayed.
c.
Run mpls rsvp-te srefresh
Srefresh is enabled.
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By default, Srefresh is disabled globally.
●
Perform the following steps in the interface view.
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The interface view is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run mpls rsvp-te srefresh
Srefresh is enabled.
By default, Srefresh is disabled on all interfaces.
e.
(Optional) Run mpls rsvp-te timer retransmission { increment-value
increment | retransmit-value interval } *
The retransmission parameters are set.
By default, increment is set to 1, and interval is set to 5000 milliseconds.
----End
6.10.5 Configuring RSVP Hello Extension
Context
The RSVP Hello extension mechanism is used to fast detect reachability of RSVP
neighbors. When the mechanism detects that a neighboring RSVP node is
unreachable, the MPLS TE tunnel is torn down.
For details about the RSVP Hello extension mechanism, see RFC 3209.
Perform the following configurations on each node of the MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls rsvp-te hello
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RSVP Hello extension function is enabled on this node.
By default, the RSVP hello extension is disabled.
Step 4 Run mpls rsvp-te hello-lost times
The permitted maximum number of dropped Hello messages is set.
When the RSVP Hello extension is enabled, by default, Hello ACK messages
cannot be received for consecutive three times, exceeding which the link is
regarded as faulty, and the TE tunnel is torn down.
Step 5 Run mpls rsvp-te timer hello interval
The interval for sending Hello messages is set.
When the RSVP Hello extension is enabled, by default, the interval of Hello
message is 3 seconds.
If the interval is modified, the modification takes effect after the timer expires.
Step 6 Run quit
Return to the system view.
Step 7 Run interface interface-type interface-number
The interface view of the RSVP-TE-enabled interface is displayed.
Step 8 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 9 Run mpls rsvp-te hello
The RSVP Hello extension function is enabled on the interface.
----End
6.10.6 Configuring the RSVP Message Format
Context
You can adjust object information in RSVP messages by configuring the RSVP
message format. In scenarios where an RSVP-TE tunnel is deployed, when devices
from other vendors on the RSVP-TE tunnel use different format of RSVP message,
you can modify the format of RSVP messages to be sent by the Huawei device to
implement interworking.
You can configure the transit and egress nodes to add the down-reason object in
an RSVP message to be sent, facilitating fault locating.
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Procedure
●
Configure the formats of objects in an RSVP message.
Perform the following steps on each node of the MPLS TE tunnel:
a.
Run system-view
The system view is displayed.
b.
Run mpls
The MPLS view is displayed.
c.
Run mpls rsvp-te send-message { suggest-label | extend-class-type
value-length-type | session-attribute without-affinity | down-reason }
The formats of objects are specified for RSVP messages to be sent.
The configuration guidelines of this command are as follows:
●
n
If a non-Huawei device requires the suggest-label object in a Path
message sent by a Huawei device, specify suggest-label.
n
If a non-Huawei device uses the value-length-type (VLT) encoding
format of the extended-class-type object but a Huawei device uses
the type-length-value (TLV) encoding format of the extended-classtype object, specify extend-class-type value-length-type.
n
If a non-Huawei device does not support the session-attribute object
sent by a Huawei device and the session-attribute object sent by the
Huawei device has an affinity attribute, specify session-attribute
without-affinity.
n
If you want an ingress to learn RSVP-TE tunnel Down causes of the
transit and egress nodes, run the mpls rsvp-te send-message downreason command.
Configure the format of the Record Route Object (RRO) in an Resv message.
When the format in an Resv message sent by a non-Huawei device connected
to the Huawei device is different from that on the Huawei device, run the
following command to adjust the format of Resv messages on the Huawei
device to be the same as that on the non-Huawei device to implement
interworking.
Perform the following configurations on the transit and egress nodes of an
MPLS TE tunnel.
a.
Run system-view
The system view is displayed.
b.
Run mpls
The MPLS view is displayed.
c.
Run the following commands as required.
n
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On a transit node, run the mpls rsvp-te resv-rro transit
{ { incoming | incoming-with-label } | { routerid | routerid-withlabel } | { outgoing | outgoing-with-label } } * command.
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n
6 MPLS TE Configuration
On an egress, run the mpls rsvp-te resv-rro egress { { incoming |
incoming-with-label } | { routerid | routerid-with-label } } *
command.
----End
6.10.7 Configuring RSVP Authentication
Context
RSVP key authentication prevents an unauthorized node from setting up RSVP
neighbor relationships with the local node or generating forged packets to attack
the local node. By default, RSVP authentication is not configured. Configuring
RSVP authentication is recommended to ensure system security.
RSVP key authentication prevents the following unauthorized means of setting up
RSVP neighbor relationships, protecting the local node from attacks (such as
malicious reservation of high bandwidth):
●
An unauthorized node attempts to set up a neighbor relationship with the
local node.
●
A remote node generates and sends forged RSVP messages to set up a
neighbor relationship with the local node.
RSVP key authentication alone cannot prevent anti-replay attacks or RSVP
message mis-sequence during network congestion. RSVP message mis-sequence
causes authentication termination between RSVP neighbors. The handshake and
message window functions, together with RSVP key authentication, can prevent
the preceding problems.
The RSVP authentication lifetime is configured, preventing unceasing RSVP
authentication. In the situation where no CR-LSP exists between RSVP neighbors,
the neighbor relationship is kept Up until the RSVP authentication lifetime expires.
The RSVP key authentication is configured either in the interface view or the MPLS
RSVP-TE neighbor view:
●
Configure RSVP key authentication in the interface view: the RSVP key
authentication is performed between directly connected nodes.
●
Configure RSVP key authentication in the MPLS RSVP-TE neighbor view: the
RSVP key authentication is performed between neighboring nodes, which is
recommended.
Perform the following configurations on each node of the MPLS TE tunnel.
NOTICE
The configuration must be complete on two neighboring nodes within three
refreshing intervals. If the configuration is not complete on either of the two
neighboring nodes after three intervals elapse, the session goes Down.
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Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run either of the following commands to enter the interface view or the MPLS
RSVP-TE neighbor view:
●
To enter the interface view of an MPLS TE tunnel, run interface interface-type
interface-number
RSVP key authentication configured in the interface view takes effect only on
the current interface and has the lowest preference.
On an Ethernet interface, run the undo portswitch command to switch the working mode
of the interface to Layer 3 mode.
●
To enter the MPLS RSVP-TE neighbor view, run mpls rsvp-te peer ip-address
–
When ip-address is specified as an interface address but not the LSR ID of
the RSVP neighbor, key authentication is based on this neighbor's
interface address. This means that RSVP key authentication takes effect
only on the specified interface of the neighbor, providing high security. In
this case, RSVP key authentication has the highest preference.
–
When ip-address is specified as an address equal to the LSR ID of the
RSVP neighbor, key authentication is based on the neighbor's LSR ID. This
means that RSVP key authentication takes effect on all interfaces of the
neighbor. In this case, this RSVP key authentication has the higher
preference than that configured in the interface view, but has the lower
preference than that configured based on the neighbor interface address.
If a neighbor node is identified by its LSR-ID, CSPF must be enabled on two neighboring
devices where RSVP authentication is required.
Step 3 Run mpls rsvp-te authentication { { cipher | plain } auth-key | keychain
keychain-name }
The authentication key is configured.
HMAC-MD5 or keychain authentication is enabled by configuring one of the
following optional parameters:
●
cipher: configures HMAC-MD5 authentication with keys displayed in
ciphertext.
●
plain: configures HMAC-MD5 authentication with keys displayed in plaintext.
●
keychain: configures keychain authentication by using a globally configured
keychain. At present, only HMAC-MD5 authentication is supported.
NOTICE
Note that HMAC-MD5 encryption algorithm cannot ensure security. Keychain
authentication is recommended.
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Step 4 (Optional) Run mpls rsvp-te authentication lifetime lifetime
The RSVP authentication lifetime is set.
lifetime is in the format of HH:MM:SS. The value ranges from 00:00:01 to 23:59:59.
By default, the time is 00:30:00, that is, 30 minutes.
RSVP neighbors to remain the neighbor relationship when no CR-LSP exists
between them until the RSVP authentication lifetime expires. Configuring the
RSVP authentication time does not affect the existing CR-LSPs.
Step 5 (Optional) Run mpls rsvp-te authentication handshake
The handshake function is configured.
The handshake function helps a device to establish an RSVP neighbor relationship
with its neighbor. If a device receives RSVP messages from a neighbor, with which
the device has not established an RSVP authentication relationship, the device will
send Challenge messages carrying local identifier to this neighbor. After receiving
the Challenge messages, the neighbor returns Response messages carrying the
identifier the same as that in the Challenge messages. After receiving the
Response messages, the local end checks the identifier carried in the Response
messages. If the identifier in the Response messages is the same as the local
identifier, the device determines to establish an RSVP authentication relationship
with its neighbor.
If you run the mpls rsvp-te authentication lifetime lifetime command after configuring
the handshake function, note that the RSVP authentication lifetime must be greater than
the interval for sending RSVP refresh messages configured by mpls rsvp-te timer refresh
command.
If the RSVP authentication lifetime is smaller than the interval for sending RSVP refresh
messages, the RSVP authentication relationship will be deleted because no RSVP refresh
message is received within the RSVP authentication lifetime. In such a case, after the next
RSVP refresh message is received, the handshake operation is triggered. Repeated
handshake operations will cause RSVP tunnels unable to be set up or cause RSVP tunnels to
be deleted.
Step 6 (Optional) Run mpls rsvp-te authentication window-size window-size
The message window function is configured.
window-size is the number of valid sequence numbers carried in RSVP messages
that a device can save.
The default window size is 1, which means that a device saves only the largest
sequence number of the RSVP message from neighbors.
When window-size is larger than 1, it means that a device accepts several valid
sequence numbers.
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If RSVP is enabled on an Eth-Trunk interface, only one neighbor relationship is established
on the trunk link between RSVP neighbors. Therefore, any member interface of the trunk
interface receives RSVP messages in a random order, resulting in RSVP message missequence. Configuring RSVP message window size prevents RSVP message mis-sequence.
The window size larger than 32 is recommended. If the window size is set too small, the
RSVP packets are discarded because the sequence number is beyond the range of the
window size, causing an RSVP neighbor relationship to be terminated.
Step 7 Run quit
Return to the system view.
Step 8 (Optional) Set an interval at which a Challenge message is retransmitted and the
maximum number of times that a Challenge message can be retransmitted.
If Authentication messages exchanged between two RSVP nodes are out of order,
a node sends a Challenge message to the other one to request for connection
restoration. If no reply to the Challenge message is received, the node retransmits
the Challenge message at a specified interval. If no reply is received after the
maximum number of retransmission times is reached, the neighbor relationship is
not restored. If a reply is received before the maximum number of retransmission
times is reached, the neighbor relationship is restored, and the number of
retransmission times is cleared for the Challenge message.
If the interval at which a Challenge message is retransmitted or the maximum
number of times that a Challenge message can be retransmitted does not meet
your RSVP authentication success ratio requirement, perform the following
configurations:
1.
Run mpls
The MPLS view is displayed.
2.
Run mpls rsvp-te retrans-timer challenge retransmission-interval
The interval at which a Challenge message is retransmitted is specified.
The default interval is 1000 ms.
3.
Run mpls rsvp-te challenge-lost max-miss-times
The maximum number of times that a Challenge message can be
retransmitted is specified.
The default value is 3.
----End
6.10.8 Verifying the Configuration of Adjusting RSVP-TE
Signaling Parameters
Prerequisites
The configurations of adjusting RSVP signaling parameters are complete.
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Procedure
●
Run the display mpls rsvp-te command to check related information about
RSVP-TE.
●
Run the display default-parameter mpls rsvp-te command to check default
parameters of RSVP-TE.
●
Run the display mpls rsvp-te session ingress-lsr-id tunnel-id egress-lsr-id
command to check information about the specified RSVP session.
●
Run the display mpls rsvp-te psb-content [ ingress-lsr-id tunnel-id lsp-id ]
command to check information about RSVP-TE PSB.
●
Run the display mpls rsvp-te rsb-content [ ingress-lsr-id tunnel-id lsp-id ]
command to check information about RSVP-TE RSB.
●
Run the display mpls rsvp-te statistics { global | interface [ interface-type
interface-number ] } command to check RSVP-TE statistics.
●
Run the display mpls rsvp-te peer [ interface interface-type interfacenumber ] command to view information about the RSVP neighbor on an
RSVP-TE-enabled interface.
----End
6.11 Adjusting the Path of a CR-LSP
CSPF uses the TEDB and constraints to calculate appropriate paths and establishes
CR-LSPs through the signaling protocol. MPLS TE provides many methods to affect
CSPF computation to adjust the CR-LSP path.
Pre-configuration Tasks
Before adjusting the path of a CR-LSP, complete the following task:
●
Configure a dynamic MPLS TE tunnel. For details, see 6.8 Configuring a
Dynamic MPLS TE Tunnel.
Configuration Procedure
The following configurations are optional and can be performed in any sequence.
6.11.1 Configuring Tie-Breaking of CSPF
Context
You can configure the CSPF tie-breaking function to select a path from multiple
paths with the same weight value.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
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Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls te tie-breaking { least-fill | most-fill | random }
CR-LSP tie-breaking policy for the LSR is configured.
Tie-breaking policies are classified as follows:
●
least-fill: the route with the smallest ratio of the occupied available
bandwidth to the maximum reservable bandwidth is selected.
●
most-fill: the route with the largest ratio of the occupied available bandwidth
to the maximum reservable bandwidth is selected.
●
random: selects a route randomly.
The default tie-breaking policy is random.
The maximum reservable bandwidth is the bandwidth configured by the command mpls te
bandwidth max-reservable-bandwidth bw-value.
Step 4 Run quit
Return to the system view.
Step 5 Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
Step 6 Run mpls te tie-breaking { least-fill | most-fill | random }
The CR-LSP tie-breaking policy for current tunnel is configured.
The parameters have the same functions as those used in step 3.
Step 7 Run mpls te commit
The current tunnel configuration is committed.
The tunnel preferentially takes the tie-breaking policy configured in its tunnel interface
view. If the tie-breaking policy is not configured in the tunnel interface view, the
configuration in the MPLS view is used.
----End
6.11.2 Configuring Metrics for Path Calculation
Context
You can configure the metric type that is used for setting up a tunnel.
Procedure
●
Specifying the metric type used by the tunnel
Perform the following configurations on the ingress node of an MPLS TE
tunnel.
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a.
6 MPLS TE Configuration
Run system-view
The system view is displayed.
b.
Run interface tunnel interface-number
The tunnel interface view is displayed.
c.
Run mpls te path metric-type { igp | te }
The metric type for path computation is configured.
d.
Run mpls te commit
The current configuration of the tunnel is committed.
e.
Run quit
Return to the system view.
f.
(Optional) Run mpls
The MPLS view is displayed.
g.
(Optional) Run mpls te path metric-type { igp | te }
The path metric type used by the tunnel during route selection is
specified.
If the mpls te path metric-type command is not run in the tunnel
interface view, the metric type in the MPLS view is used; otherwise, the
metric type in the tunnel interface view is used.
By default, path metric type used by the tunnel during route selection is
TE.
●
(Optional) Configuring the TE metric value of the path
If the metric type of a specified tunnel is TE, you can modify the TE metric
value of the path on the outbound interface of the ingress and the transit
node by performing the following configurations.
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The view of the MPLS-TE-enabled interface is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run mpls te metric value
The TE metric value of the path is configured.
By default, the path uses the IGP metric value as the TE metric value.
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If the IGP is OSPF and the current device is a stub router, the mpls te metric
command does not take effect.
----End
6.11.3 Configuring CR-LSP Hop Limit
Context
Similar to the administrative group and the affinity property, the hop limit is a
condition for CR-LSP path selection and is used to specify the number of hops
along a CR-LSP to be set up.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
Step 3 Run mpls te hop-limit hop-limit-value [ best-effort | secondary ]
The number of hops along the CR-LSP is set. The hop-limit-value is an integer
ranging from 1 to 32.
Step 4 Run mpls te commit
The current tunnel configuration is committed.
----End
6.11.4 Configuring Route Pinning
Context
By configuring the route pinning function, you can use the path that is originally
selected, rather than another eligible path, to set up a CR-LSP.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
If route pinning is enabled, the MPLS TE re-optimization cannot be used at the same time.
Procedure
Step 1 Run system-view
The system view is displayed.
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Step 2 Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
Step 3 Run mpls te route-pinning
Route pinning is enabled.
By default, route pinning is disabled.
Step 4 Run mpls te commit
The current tunnel configuration is committed.
----End
6.11.5 Configuring Administrative Group and Affinity Property
Context
The configuration of the administrative group affects only LSPs to be set up; the
configuration of the affinity property affects established LSPs by recalculating the
paths.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface interface-type interface-number
The interface view of the MPLS-TE-enabled interface is displayed.
Step 3 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 4 Run mpls te link administrative group value
The administrative group of the MPLS TE link is configured.
The modification of administrative group takes effect only on LSPs that are
established after modification.
Step 5 Run quit
Return to the system view.
Step 6 Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
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Step 7 Run mpls te affinity property properties [ mask mask-value ] [ secondary | besteffort ]
The affinity for the tunnel is configured.
By default, the values of administrative group, affinity property, and mask are all
0x0.
After the modified affinity property is committed, the established LSP in this
tunnel may be affected and the system recalculates the path for the TE tunnel.
Step 8 Run mpls te commit
The current tunnel configuration is committed.
----End
6.11.6 Configuring SRLG
Context
In the networking scenario where the hot standby CR-LSP is set up or TE FRR is
enabled, configure the SRLG attribute on the outbound interface of the ingress
node of the MPLS TE tunnel or the PLR and the other member links of the SRLG
to which the outbound interface belongs.
Configuring SRLG includes:
●
Configuring SRLG for the link
●
Configuring SRLG path calculation mode for the tunnel
●
Deleting the member interfaces of all SRLGs
Perform the following configurations according to actual networking.
Procedure
●
Configuring SRLG for the link
Perform the following configurations on the links which are in the same SRLG.
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The interface view is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run mpls te srlg srlg-number
The interface is configured as an SRLG member.
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On a network with CR-LSP hot standby or TE FRR configured, the SRLG
attribute can be configured for the outbound interface of the ingress
node of the MPLS TE tunnel or the PLR and other members of the SRLG
to which the outbound interface belongs. A link joins an SRLG after the
SRLG attribute is configured on an outbound interface of the link.
●
Configuring SRLG path calculation mode for the tunnel
Perform the following configurations on the ingress node of the hot-standby
tunnel or the TE FRR tunnel.
a.
Run system-view
The system view is displayed.
b.
Run mpls
The MPLS view is displayed.
c.
Run mpls te srlg path-calculation [ strict | preferred ]
The SRLG path calculation mode is configured.
If you specify the strict keyword, CSPF avoids the following links when
calculating the bypass CR-LSP or backup CR-LSP:
n
Link with the same SRLG attributes as SRLG attributes of the primary
CR-LSP
n
All links along the primary CR-LSP regardless of whether the links are
configured with SRLG attributes
CSPF does not exclude the nodes that the primary CR-LSP passes.
● If you specify the strict keyword, CSPF always considers the SRLG as a
constraint when calculating the path for the bypass CR-LSP or the backup CRLSP.
● If you specify the preferred keyword, CSPF tries to calculate the path which
avoids the links in the same SRLG as protected interfaces; if the calculation
fails, CSPF does not consider the SRLG as a constraint.
●
Delete the member interfaces of all SRLGs.
Perform the following configurations to delete member interfaces of all SRLGs
from a node of the MPLS TE tunnel.
a.
Run system-view
The system view is displayed.
b.
Run mpls
The MPLS view is displayed.
c.
Run undo mpls te srlg all-config
The member interfaces of all SRLGs are deleted from the MPLS TE node.
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The undo mpls te srlg all-config does not delete an SRLG-based path
calculation mode configured in the mpls te srlg path-calculation command in
the MPLS view.
----End
6.11.7 Associating CR-LSP Establishment with the Overload
Setting
Context
A node becomes overloaded in the following situations:
●
When the node is transmitting a large number of services and its system
resources are exhausted, the node marks itself overloaded.
●
When the node is transmitting a large number of services and its CPU is
overburdened, an administrator can run the set-overload command to mark
the node overloaded.
If there are overloaded nodes on an MPLS TE network, associate CR-LSP
establishment with the IS-IS overload setting to ensure that CR-LSPs are
established over paths excluding overloaded nodes. This configuration prevents
overloaded nodes from being further burdened and improves CR-LSP reliability.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls te path-selection overload
CR-LSP establishment is associated with the IS-IS overload setting. This association
allows CSPF to calculate paths excluding overloaded IS-IS nodes.
Before the association is configured, the mpls te record-route command must be
run to enable the route and label record.
Traffic travels through an existing CR-LSP before a new CR-LSP is established.
After the new CR-LSP is established, traffic switches to the new CR-LSP and the
original CR-LSP is deleted. This traffic switchover is performed based on the MakeBefore-Break mechanism. Traffic is not dropped during the switchover.
The mpls te path-selection overload command has the following influences on
the CR-LSP establishment:
●
CSPF recalculates paths excluding overloaded nodes for established CR-LSPs.
●
CSPF calculates paths excluding overloaded nodes for new CR-LSPs.
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This command does not take effect on bypass tunnels.
If the ingress or egress is marked overloaded, the mpls te path-selection overload
command does not take effect. The established CR-LSPs associated with the ingress or
egress will not be reestablished and new CR-LSPs associated with the ingress or egress will
also not be established.
----End
6.11.8 Configuring Failed Link Timer
Context
CSPF uses a locally-maintained traffic-engineering database (TEDB) to calculate
the shortest path to the destination address. Then, the signaling protocol applies
for and reserves resources for the path. In the case of a link on a network is faulty,
if the routing protocol fails to notify CSPF of updating the TEDB in time, this may
cause the path calculated by CSPF to contain the faulty link.
As a result, the control packets, such as RSVP Path messages, of a signaling
protocol are discarded on the faulty link. Then, the signaling protocol returns an
error message to the upstream node. Receiving the link error message on the
upstream node triggers CSPF to recalculate a path. The path recalculated by CSPF
and returned to the signaling protocol still contains the faulty link because the
TEDB is not updated. The control packets of the signaling protocol are still
discarded and the signaling protocol returns an error message to trigger CSPF to
recalculate a path. The procedure repeats until the TEDB is updated.
To avoid the preceding situation, when the signaling protocol returns an error
message to notify CSPF of a link failure, CSPF sets the status of the faulty link to
INACTIVE and enables a failed link timer. Then, CSPF does not use the faulty link
in path calculation until CSPF receives a TEDB update event or the failed link timer
expires.
Before the failed link timer expires, if a TEDB update event is received, CSPF
deletes the failed link timer.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls te cspf timer failed-link interval
The failed link timer is configured.
By default, the failed link timer is set to 10 seconds.
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The failed link timer is a local configuration. If the failed link timers of nodes are
set to different values, a failed link that is in ACTIVE state on one node may be in
INACTIVE state on other nodes.
----End
6.11.9 Configuring Flooding Threshold
Context
The bandwidth flooding threshold indicates the ratio of the link bandwidth
occupied or released by a TE tunnel to the link bandwidth remained in the TEDB.
If the link bandwidth changes little, bandwidth flooding wastes network resources.
For example, if link bandwidth is 100 Mbit/s and 100 TE tunnels (with bandwidth
as 1 Mbit/s) are created along this link, bandwidth flooding need be performed for
100 times.
If the flooding threshold is set to 10%, bandwidth flooding is not performed when
tunnel 1 to tunnel 9 are created. When tunnel 10 is created, the bandwidth of
tunnel 1 to tunnel 10 (10 Mbit/s in total) is flooded. Similarly, bandwidth flooding
is not performed when tunnel 11 to tunnel 18 are created. When tunnel 19 is
created, the bandwidth of tunnel 11 to tunnel 19 is flooded. Therefore, configuring
bandwidth flooding threshold can reduce the times of bandwidth flooding and
hence ensure the efficient use of network resources.
By default, on a link, IGP flood information about this link and CSPF updates the
TEDB accordingly if one of the following conditions is met:
●
The ratio of the bandwidth reserved for an MPLS TE tunnel to the bandwidth
remained in the TEDB is equal to or higher than 10%.
●
The ratio of the bandwidth released by an MPLS TE tunnel to the bandwidth
remained in the TEDB is equal to or higher than 10%.
Perform the following configurations on the ingress or transit node of an MPSL TE
tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface interface-type interface-number
The view of the MPLS-TE-enabled interface is displayed.
Step 3 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
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Step 4 Run mpls te bandwidth change thresholds { down | up } percent
The threshold of bandwidth flooding is set.
----End
6.11.10 Verifying the Configuration of Adjusting the Path of a
CR-LSP
Prerequisites
The configurations of adjusting the path of a CR-LSP are complete.
Procedure
●
Run the display mpls te tunnel verbose command to check information
about the MPLS TE tunnel.
●
Run the display mpls te srlg { srlg-number | all } command to check the
SRLG configuration and interfaces in the SRLG.
●
Run the display mpls te link-administration srlg-information [ interface
interface-type interface-number ] command to check the SRLG that interfaces
belong to.
●
Run the display mpls te tunnel c-hop [ tunnel-name ] [ lsp-id ingress-lsr-id
session-id lsp-id ] command to check path computation results of tunnels.
●
Run the display default-parameter mpls te cspf command to check default
CSPF settings.
----End
6.12 Adjusting the Establishment of an MPLS TE
Tunnel
During establishment of an MPLS TE tunnel, specific configurations are required in
practice. MPLS TE provides multiple methods to adjust establishment of MPLS TE
tunnels.
Pre-configuration Tasks
Before adjusting establishment of an MPLS TE tunnel, complete the following task:
●
Configure a dynamic MPLS TE tunnel. For details, see 6.8 Configuring a
Dynamic MPLS TE Tunnel.
Configuration Procedure
The following configurations are optional and can be performed in any sequence.
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6.12.1 Configuring Loop Detection
Context
In the loop detection mechanism, a maximum number of 32 hops are allowed on
an LSP. If information about the local LSR is recorded in the path information
table, or the number of hops on the path exceeds 32, this indicates that a loop
occurs and the LSP fails to be set up. By configuring the loop detection function,
you can prevent loops.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
Step 3 Run mpls te loop-detection
The loop detection on tunnel creation is enabled.
By default, loop detection is disabled.
Step 4 Run mpls te commit
The current tunnel configuration is committed.
----End
6.12.2 Configuring Route Record and Label Record
Context
By configuring route record and label record, you can determine whether to record
routes and labels during the establishment of an RSVP-TE tunnel.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
Step 3 Run mpls te record-route [ label ]
The route and label are recorded when establishing the tunnel.
By default, routes and labels are not recorded.
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Step 4 Run mpls te commit
The current tunnel configuration is committed.
----End
6.12.3 Configuring Re-optimization for CR-LSP
Context
By configuring the tunnel re-optimization function, you can periodically recompute
routes for a CR-LSP. If the recomputed routes are better than the routes in use, a
new CR-LSP is then established according to the recomputed routes. In addition,
services are switched to the new CR-LSP, and the previous CR-LSP is deleted.
If an upstream node on an MPLS network is busy but its downstream node is idle
or an upstream node is idle but its downstream node is busy, a CR-LSP may be
torn down before the new CR-LSP is established, causing a temporary traffic
interruption. In this case, you can configure the switching and deletion delays.
● If the re-optimization is enabled, the route pinning cannot be used at the same time.
● The CR-LSP re-optimization cannot be configured when the resource reservation style is
FF.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
Step 3 Run mpls te reoptimization [ frequency interval ]
Periodic re-optimization is enabled.
By default, re-optimization is disabled. The default periodic re-optimization
interval is 3600 seconds.
Step 4 Run mpls te commit
The current tunnel configuration is committed.
Step 5 Run quit
The system view is displayed.
Step 6 (Optional) Set the switching and deletion delays.
1.
Run mpls
The MPLS view is displayed.
2.
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The switching and deletion delays are set.
By default, the switching delay is 5000 ms and the deletion delay is 7000 ms.
Step 7 Run return
Back to the user view.
Step 8 (Optional) Run mpls te reoptimization [ tunnel interface-number ]
Manual re-optimization is enabled.
After you configure the automatic re-optimization in the tunnel interface view,
you can return to the user view and run the mpls te reoptimization command to
immediately re-optimize all tunnels or the specified tunnel on which the
automatic re-optimization is enabled. After you perform the manual reoptimization, the timer of the automatic re-optimization is reset and counts again.
----End
6.12.4 Configuring Tunnel Reestablishment Parameters
Context
By configuring the tunnel reestablishment function, you can periodically
recompute the route for a CR-LSP. If the route in recomputation is better than the
route in use, a new CR-LSP is then established according to the recomputed route.
In addition, services are switched to the new CR-LSP, and the previous CR-LSP is
deleted.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
Step 3 Run mpls te timer retry interval
The interval for re-establishing a tunnel is specified.
By default, the interval for re-establishing a tunnel is 30 seconds.
Step 4 Run mpls te commit
The current tunnel configuration is committed.
If the establishment of a tunnel fails, the system attempts to reestablish the
tunnel within the set interval and the maximum number of attempts is the set
reestablishment times.
----End
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6.12.5 Configuring the RSVP Signaling Delay-Trigger Function
Context
In the case that a fault occurs on an MPLS network, a great number of RSVP CRLSPs need to be reestablished. This causes consumption of a large number of
system resources. By configuring the delay for triggering the RSVP signaling, you
can reduce the consumption of system resources when establishing an RSVP CRLSP.
Perform the following configurations on each node on which multiple CR-LSPs
need to be reestablished.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls te signaling-delay-trigger enable
The RSVP signaling delay-trigger function is enabled.
By default, the RSVP signaling delay-trigger function is not enabled.
----End
6.12.6 Configuring the Tunnel Priority
Context
In the process of establishing a CR-LSP, if no path with the required bandwidth
exists, you can perform bandwidth preemption according to setup priorities and
hold priorities.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
Step 3 Run mpls te priority setup-priority [ hold-priority ]
The priority for the tunnel is configured.
Both the setup priority and the hold priority range from 0 to 7. The smaller the
value is, the higher the priority is.
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By default, both the setup priority and the hold priority are 7. If only the setup
priority value is set, the hold priority value is the same as the setup priority value.
The setup priority should not be higher than the hold priority. So the value of the setup
priority must not be less than that of the hold priority.
Step 4 Run mpls te commit
The current tunnel configuration is committed.
----End
6.12.7 Verifying the Configuration of Adjusting the
Establishment of an MPLS TE Tunnel
Prerequisites
The configurations of adjusting establishment of an MPLS TE tunnel are complete.
Procedure
●
Run the display mpls te tunnel-interface [ tunnel interface-number ]
command to check information about the tunnel interface.
----End
6.13 Configuring CR-LSP Backup
CR-LSP backup provides an end-to-end protection mechanism. If a primary CR-LSP
fails, traffic rapidly switches to a backup CR-LSP, ensuring uninterrupted traffic
transmission.
Pre-configuration Tasks
Before configuring CR-LSP backup, complete the following tasks:
●
Configure a dynamic MPLS TE or DS-TE tunnel. For details, see 6.8
Configuring a Dynamic MPLS TE Tunnel.
●
Enable MPLS, MPLS TE, and RSVP-TE globally and on interfaces of each node
along a backup CR-LSP.
If CR-LSP hot standby is configured, perform the operation of 6.19 Configuring Static BFD for
CR-LSPs or 6.20 Configuring Dynamic BFD for CR-LSPs to implement fast switching at the
millisecond level.
Configuration Procedure
Configuring forcible switchover, locking a backup CR-LSP attribute template,
configuring dynamic bandwidth for hot-standby CR-LSPs, and configuring a besteffort path are optional.
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6.13.1 Creating a Backup CR-LSP
Context
CR-LSP backup can be configured to allow traffic to switch from a primary CR-LSP
to a backup CR-LSP, providing end-to-end protection.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel tunnel-number
The tunnel interface view is displayed.
Step 3 Run mpls te backup hot-standby
or run mpls te backup ordinary
The mode of establishing a backup CR-LSP is configured.
If hot-standby is specified, a hot-standby CR-LSP is set up. To implement fast
switching at the millisecond level, perform the operation of 6.19 Configuring
Static BFD for CR-LSPs or 6.20 Configuring Dynamic BFD for CR-LSPs.
A tunnel interface cannot be used for both a bypass tunnel and a backup tunnel. A
protection failure will occur if the mpls te backup and mpls te bypass-tunnel commands
are run on the tunnel interface, or if the mpls te backup and mpls te protected-interface
commands are run on the tunnel interface. For details on how to create a bypass CR-LSP,
see Configuring Manual TE FRR or Configuring Auto TE FRR.
A tunnel interface cannot be used for both a bypass tunnel and a protection tunnel in a
tunnel protection group. A protection failure will occur if the mpls te backup and mpls te
protection tunnel commands are run on the tunnel interface. For details on how to create
a protection tunnel, see Configuring a Tunnel Protection Group.
After hot standby or ordinary backup is configured, the system selects a path for a
backup CR-LSP. To specify a path for a backup CR-LSP, repeatedly perform one or
more of steps 4 to 6. When hot standby is configured, repeatedly perform one or
more of steps 7 to 9.
Step 4 (Optional) Run mpls te path explicit-path path-name secondary
An explicit path is specified for the backup CR-LSP.
Use a separate explicit path for the backup CR-LSP to prevent the backup CR-LSP
from completely overlapping its primary CR-LSP. Protection will fail if the backup
CR-LSP completely overlaps its primary CR-LSP.
The mpls te path explicit-path command can be run successfully only after an
explicit path is set up by running the explicit-path path-name command in the
system view, and the nodes on the path are specified.
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Step 5 (Optional) Run mpls te affinity property properties [ mask mask-value ]
secondary
The affinity property is configured for the backup CR-LSP.
By default, the affinity property used by the backup CR-LSP is 0x0 and the mask is
0x0.
Step 6 (Optional) Run mpls te hop-limit hop-limit-value secondary
The hop limit is set for the backup CR-LSP.
The default hop limit is 32.
Step 7 (Optional) Run mpls te backup hot-standby overlap-path
The path overlapping function is configured. This function allows a hot-standby
CR-LSP to use links of a primary CR-LSP.
By default, the path overlapping function is disabled. If the path overlapping
function is disabled, a hot-standby CR-LSP may fail to be set up.
After the path overlapping function is configured, the path of the hot-standby CRLSP partially overlaps the path of the primary CR-LSP when the hot-standby CRLSP cannot exclude paths of the primary CR-LSP.
Step 8 (Optional) Run mpls te backup hot-standby wtr interval
The WTR time for a switchback is set.
By default, the WTR time for switching traffic from a hot-standby CR-LSP to a
primary CR-LSP is 10 seconds.
Step 9 (Optional) Run mpls te backup hot-standby mode { revertive [ wtr interval ] |
non-revertive }
A revertive mode is specified.
By default, the revertive mode is used.
Step 10 Run mpls te commit
The configuration is committed.
----End
6.13.2 (Optional) Configuring Forcible Switchover
Context
If a backup CR-LSP has been established and a primary CR-LSP needs to be
adjusted, configure the forcible switchover function to switch traffic from the
primary CR-LSP to the backup CR-LSP. After adjusting the primary CR-LSP, switch
traffic back to the primary CR-LSP. This process prevents traffic loss during the
primary CR-LSP adjustment.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
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Procedure
●
Before adjusting a primary CR-LSP, perform the following configurations.
a.
Run system-view
The system view is displayed.
b.
Run interface tunnel tunnel-number
The MPLS TE tunnel interface view is displayed.
c.
Run hotstandby-switch force
Traffic is switched to a backup CR-LSP.
NOTICE
To prevent traffic loss, check that a backup CR-LSP has been established
before running the hotstandby-switch force command.
●
After adjusting the primary CR-LSP, perform the following configurations.
a.
Run system-view
The system view is displayed.
b.
Run interface tunnel tunnel-number
The MPLS TE tunnel interface view is displayed.
c.
Run hotstandby-switch clear
Traffic is switched backup to the primary CR-LSP.
----End
6.13.3 (Optional) Locking a Backup CR-LSP Attribute
Template
Context
A maximum of three hot-standby or ordinary backup attribute templates can be
used for establishing a hot-standby or an ordinary CR-LSP. TE attribute templates
are prioritized. The system attempts to use each template in ascending order by
priority to establish a backup CR-LSP.
If an existing backup CR-LSP is set up using a lower-priority attribute template,
the system automatically attempts to set up a new backup CR-LSP using a higherpriority attribute template, which is unneeded sometimes. If a CR-LSP has been
established using the locked CR-LSP attribute template, the CR-LSP will not be
unnecessarily reestablished using another template with a higher priority. Locking
a CR-LSP attribute template allows the existing CR-LSP to keep transmitting traffic
without triggering unneeded traffic switchovers, efficiently using system resources.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
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Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel tunnel-number
The tunnel interface view is displayed.
Step 3 Run mpls te primary-lsp-constraint { dynamic | lsp-attribute lsp-attributename }
An attribute template is specified for setting up a primary CR-LSP.
Step 4 Run either of the following commands as needed to establish a backup CR-LSP:
●
To establish an ordinary backup CR-LSP, run mpls te ordinary-lsp-constraint
number { dynamic | lsp-attribute lsp-attribute-name }
●
To establish a hot-standby CR-LSP, run mpls te hotstandby-lsp-constraint
number { dynamic | lsp-attribute lsp-attribute-name }
Step 5 Run either of the following commands as needed to lock a backup CR-LSP
attribute template:
●
To lock an attribute template for an ordinary backup CR-LSP, run mpls te
backup ordinary-lsp-constraint lock
●
To lock an attribute template for a hot-standby CR-LSP, run mpls te backup
hotstandby-lsp-constraint lock
A used attribute template can be unlocked after the undo mpls te backup ordinary-lspconstraint lock or undo mpls te backup hotstandby-lsp-constraint lock command is run.
After unlocking templates, the system uses each available template in ascending order by
priority. If a template has a higher priority than that of the currently used template, the system
establishes a CR-LSP using the higher-priority template.
Step 6 Run mpls te commit
The configuration is committed.
----End
6.13.4 (Optional) Configuring Dynamic Bandwidth for HotStandby CR-LSPs
Context
Hot-standby CR-LSPs are established using reserved bandwidth resources by
default. The dynamic bandwidth function can be configured to allow the system
to create a primary CR-LSP and a hot-standby CR-LSP with the bandwidth of 0
bit/s simultaneously.
The dynamic bandwidth protection function allows a hot-standby CR-LSP to
obtain bandwidth resources only after the hot-standby CR-LSP takes over traffic
from a faulty primary CR-LSP. If the primary CR-LSP fails, traffic immediately
switches to the hot-standby CR-LSP with 0 bit/s bandwidth. The ingress node uses
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the make-before-break mechanism to reestablish a hot-standby CR-LSP. After the
new hot-standby CR-LSP has been successfully established, the ingress node
switches traffic to this CR-LSP and tears down the hot-standby CR-LSP with 0 bit/s
bandwidth. If bandwidth resources are insufficient, the ingress node is unable to
reestablish a hot-standby CR-LSP with the desired bandwidth, and therefore
switches traffic to the hot-standby CR-LSP with 0 bit/s bandwidth, ensuring
uninterrupted traffic transmission.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
●
Perform the following configurations to enable the dynamic bandwidth
function for hot-standby CR-LSPs that are established not using attribute
templates.
a.
Run system-view
The system view is displayed.
b.
Run interface tunnel tunnel-number
The tunnel interface view is displayed.
c.
Run mpls te backup hot-standby dynamic-bandwidth
The dynamic bandwidth function is enabled for hot-standby CR-LSPs.
● If a hot-standby CR-LSP has been established before the dynamic bandwidth
function is enabled, the system uses the Make-Before-Break mechanism to
establish a new hot-standby CR-LSP with the bandwidth of 0 bit/s to replace the
existing hot-standby CR-LSP.
● The undo mpls te backup hot-standby dynamic-bandwidth command can be
used to disable the dynamic bandwidth function. This allows the hot-standby CRLSP with the bandwidth of 0 bit/s to obtain bandwidth.
d.
Run mpls te commit
The configuration is committed.
●
Perform the following configurations to enable the dynamic bandwidth
function for hot-standby CR-LSPs that are established using attribute
templates.
a.
Run system-view
The system view is displayed.
b.
Run interface tunnel tunnel-number
The tunnel interface view is displayed.
c.
Run mpls te backup hotstandby-lsp-constraint dynamic-bandwidth
The dynamic bandwidth function is enabled for hot-standby CR-LSPs set
up by using an attribute template.
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● If a hot-standby CR-LSP has been established before the dynamic bandwidth
function is enabled, the system uses the Make-Before-Break mechanism to
establish a new hot-standby CR-LSP with the bandwidth of 0 bit/s to replace the
existing hot-standby CR-LSP.
● The undo mpls te backup hotstandby-lsp-constraint dynamic-bandwidth
command can be used to disable the dynamic bandwidth function of the hotstandby CR-LSP which is set up by using an attribute template. This allows the
hot-standby CR-LSP with no bandwidth to obtain bandwidth.
d.
Run mpls te commit
The configuration is committed.
----End
6.13.5 (Optional) Configuring a Best-Effort Path
Context
A best-effort path is configured on the ingress node of a primary CR-LSP to take
over traffic if both the primary and backup CR-LSPs fail.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel tunnel-number
The tunnel interface view is displayed.
Step 3 Run mpls te backup ordinary best-effort
A best-effort path is configured.
A tunnel interface cannot be used for both a best-effort path and a manually configured
ordinary backup tunnel. A protection failure will occur if the mpls te backup ordinary
best-effort and mpls te backup ordinary commands are run on the tunnel interface.
To establish a best-effort path over a specified path, run either or both of step 4
and step 5.
Step 4 (Optional) Run mpls te affinity property properties [ mask mask-value ] besteffort
The affinity property of the best-effort path is configured.
By default, the affinity property used by the best-effort path is 0x0 and the mask
is 0x0.
Step 5 (Optional) Run mpls te hop-limit hop-limit-value best-effort
The hop limit of the best-effort path is set.
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The default hop limit is 32.
Step 6 Run mpls te commit
The configuration is committed.
----End
6.13.6 Verifying the CR-LSP Backup Configuration
Prerequisites
The configurations of CR-LSP backup are complete.
Procedure
●
Run the display mpls te tunnel-interface [ tunnel tunnel-number ]
command to check information about the tunnel interface.
●
Run the display mpls te hot-standby state { all [ verbose ] | interface
tunnel interface-number } command to check information about the hotstandby status.
●
Run the display mpls te tunnel [ destination ip-address ] [ lsp-id ingress-lsrid session-id local-lsp-id ] [ lsr-role { all | egress | ingress | remote |
transit } ] [ name tunnel-name ] [ { incoming-interface | interface |
outgoing-interface } interface-type interface-number ] [ verbose ] command
to check CR-LSP information.
----End
6.14 Configuring Manual TE FRR
Manual TE FRR is a local protection mechanism used on MPLS TE networks. TE
manual FRR switches traffic on a primary MPLS TE tunnel to a manually
configured bypass tunnel if a link or node on the primary tunnel fails.
Pre-configuration Tasks
Before configuring manual MPLS TE FRR, complete the following tasks:
●
Configure a dynamic MPLS TE tunnel. For details, see 6.8 Configuring a
Dynamic MPLS TE Tunnel.
●
Enable MPLS, MPLS TE and RSVP-TE in the system view and interface view of
each node along a bypass tunnel.
●
Enable CSPF on a PLR.
Perform the operation of 6.18 Configuring Dynamic BFD for RSVP to implement fast switching
at the millisecond level.
Configuration Procedure
Except that configuring a TE FRR scanning timer and changing the PSB and RSB
timeout multiplier are optional, other configurations are mandatory.
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6.14.1 Enabling TE FRR
Context
TE FRR must be enabled for a primary tunnel before a bypass tunnel is
established.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel tunnel-number
The interface view of a primary tunnel is displayed.
Step 3 Run mpls te fast-reroute [ bandwidth ]
TE FRR is enabled.
Only the primary tunnel in a tunnel protection group can be configured together with TE
FRR on the ingress node. Neither the protection tunnel nor the tunnel protection group
itself can be used together with TE FRR. If the tunnel protection group and TE FRR are used,
neither of them takes effect.
For example, Tunnel1 and Tunnel2 are tunnel interfaces on MPLS TE tunnels and the tunnel
named Tunnel2 has a tunnel ID of 200. The mpls te protection tunnel 200 and mpls te
fast-reroute commands cannot be configured simultaneously on Tunnel1. That is, the
tunnel protection group and TE FRR cannot be used together on Tunnel1. A configuration
failure will occur if the mpls te protection tunnel 200 command is run on Tunnel1 and the
mpls te fast-reroute command is run on Tunnel2.
Step 4 Run mpls te commit
The configuration is committed.
----End
6.14.2 Configuring a Bypass Tunnel
Context
A bypass tunnel provides protection for a link or node on a primary tunnel. An
explicit path and attributes must be specified for a bypass tunnel when TE manual
FRR is being configured.
Bypass tunnels are established on selected links or nodes that are not on the
protected primary tunnel. If a link or node on the protected primary tunnel is used
for a bypass tunnel and fails, the bypass tunnel also fails to protect the primary
tunnel.
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● FRR does not take effect if multiple nodes or links fail simultaneously. After FRR
switching is performed to switch data from the primary tunnel to a bypass tunnel, the
bypass tunnel must remain Up when forwarding data. If the bypass tunnel goes Down,
the protected traffic is interrupted and FRR fails. Even though the bypass tunnel goes Up
again, traffic is unable to flow through the bypass tunnel but travels through the
primary tunnel after the primary tunnel recovers or is reestablished.
● By default, the system searches for an optimal manual FRR tunnel for each primary
tunnel every 1 second and binds the bypass tunnel to the primary tunnel if there is an
optimal bypass tunnel.
Perform the following configurations on the PLR.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel tunnel-number
The tunnel interface view of a bypass tunnel is displayed.
Step 3 Run either of the following commands to configure the IP address for the tunnel
interface:
●
To configure an IP address for the interface, run ip address ip-address { mask
| mask-length } [ sub ]
●
To configure the tunnel interface to borrow an IP address of another
interface, run ip address unnumbered interface interface-type interface-
number
A tunnel interface must have an IP address to forward traffic. An MPLS TE tunnel
is unidirectional and does not need to configure a separate IP address for the
tunnel interface. The tunnel interface usually borrows the IP address of the local
loopback interface used as an LSR ID.
Step 4 Run tunnel-protocol mpls te
MPLS TE is configured as a tunnel protocol.
Step 5 Run destination ip-address
The LSR ID of an MP is specified as the destination address of the bypass tunnel.
Step 6 Run mpls te tunnel-id tunnel-id
The tunnel ID is set for the bypass tunnel.
Step 7 (Optional) Run mpls te path explicit-path path-name
An explicit path is specified for the bypass tunnel.
Before using this command, ensure that the explicit path has been created using
the explicit-path command. Note that physical links of a bypass tunnel cannot
overlap protected physical links of the primary tunnel.
Step 8 Run mpls te bypass-tunnel
The bypass tunnel function is enabled.
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After a bypass tunnel is configured, the system automatically records routes
related to the bypass tunnel.
● A tunnel interface cannot be used for both a bypass tunnel and a backup tunnel. A
protection failure will occur if the mpls te bypass-tunnel and mpls te backup
commands are both configured on the tunnel interface.
● A tunnel interface cannot be used for both a bypass tunnel and a primary tunnel. A
protection failure will occur if the mpls te bypass-tunnel and mpls te fast-reroute
commands are both configured on the tunnel interface.
● A tunnel interface cannot be used for both a bypass tunnel and a protection tunnel in a
tunnel protection group. A protection failure will occur if the mpls te bypass-tunnel
and mpls te protection tunnel commands are both configured on the tunnel interface.
Step 9 Run mpls te protected-interface interface-type interface-number
An interface to be protected by a bypass tunnel is specified.
● A bypass tunnel protects a maximum of six physical interfaces.
● A tunnel interface cannot be used for both a bypass tunnel and a backup tunnel. A
protection failure will occur if the mpls te protected-interface and mpls te backup
commands are both configured on the tunnel interface.
Step 10 Run mpls te commit
The configuration is committed.
----End
6.14.3 (Optional) Configuring a TE FRR Scanning Timer
Context
A TE FRR-enabled device periodically refreshes the binding between a bypass CRLSP and a primary LSP at a specified interval. The PLR searches for the optimal TE
bypass CR-LSP and binds it to a primary CR-LSP. A TE FRR scanning timer is set to
determine the interval at which the binding between a bypass CR-LSP and a
primary CR-LSP is refreshed.
Perform the following configurations on the PLR.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls te timer fast-reroute [ weight ]
Set the interval at which the binding between a bypass CR-LSP and a primary CRLSP is refreshed.
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By default, the time weight used to calculate the interval is 300. And the actual
interval at which the binding between a bypass CR-LSP and a primary LSP is
refreshed depends on device performance and the maximum number of LSPs that
can be established on the device.
----End
6.14.4 (Optional) Changing the PSB and RSB Timeout
Multiplier
Context
To help allow TE FRR to operate during the RSVP GR process, the timeout
multiplier of the Path State Block (PSB) and Reservation State Block (RSB) can be
set. The setting prevents the situation where information in PSBs and RSBs is
dropped due to a timeout before the GR processes are complete for a large
number of CR-LSPs.
Perform the following configurations on the PLR.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls rsvp-te keep-multiplier keep-multiplier-number
The PSB and RSB timeout multiplier is set.
The default timeout multiplier is 3.
Setting the timeout multiplier to 5 or greater is recommended for a network where a large
number of CR-LSPs are established and RSVP GR is configured.
----End
6.14.5 Verifying the Manual TE FRR Configuration
Prerequisites
The configurations of manual TE FRR are complete.
Procedure
●
Run the display mpls lsp lsp-id ingress-lsr-id session-id lsp-id [ verbose ]
command to check information about a specified primary tunnel.
●
Run the display mpls lsp attribute bypass-inuse { inuse | not-exists | existsnot-used } command to check information about the attribute of a specified
bypass LSP.
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●
Run the display mpls lsp attribute bypass-tunnel tunnel-name command to
check information about the attribute of a bypass tunnel.
●
Run the display mpls te tunnel-interface [ tunnel interface-number | autobypass-tunnel [ tunnel-name ] ] command to check detailed information
about the tunnel interface of a specified primary or bypass tunnel.
●
Run the display mpls te tunnel path [ [ [ tunnel-name ] tunnel-name ]
[ lsp-id ingress-lsr-id session-id lsp-id ] | fast-reroute { local-protectionavailable | local-protection-inuse } | lsr-role { ingress | transit | egress } ]
command to check information about paths of a specified primary or bypass
tunnel.
●
Run the display mpls rsvp-te statistics fast-reroute command to check TE
FRR statistics.
●
Run the display mpls stale-interface [ interface-index ] [ verbose ]
command to check the information about MPLS interfaces in the Stale state.
----End
6.15 Configuring Auto TE FRR
Auto TE FRR is a local protection technique and is used to protect a CR-LSP
against link faults and node faults. Auto TE FRR does not need to be configured
manually.
Pre-configuration Tasks
Before configuring auto TE FRR, complete the following task:
●
Configure a dynamic MPLS TE tunnel. For details, see 6.8 Configuring a
Dynamic MPLS TE Tunnel.
●
Enable MPLS, MPLS TE and RSVP-TE in the system view and interface view of
each node along a bypass tunnel.
●
Enable CSPF on a PLR.
Perform the operation of 6.18 Configuring Dynamic BFD for RSVP to implement fast switching
at the millisecond level.
Configuration Procedure
Except that configuring a TE FRR scanning timer, changing the PSB and RSB
timeout multiplier, configuring auto bypass tunnel re-optimization, and
configuring interworking with other vendors are optional, other configurations are
mandatory.
6.15.1 Enabling Auto TE FRR
Context
Before configuring auto TE FRR, enable auto TE FRR globally on the PLR. To
implement link protection, enable link protection on an interface.
Perform the following configurations on the PLR.
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Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls te auto-frr
Auto TE FRR is enabled globally.
After auto TE FRR is enabled globally, link protection is enabled on all interfaces
enabled with MPLS TE.
Step 4 (Optional) Configure MPLS TE Auto FRR in the interface view.
1.
Run quit
Return to the system view.
2.
Run interface interface-type interface-number
The interface view of the outbound interface of the primary tunnel is
displayed.
3.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer
2 and Layer 3 modes.
4.
Run mpls te auto-frr { link | node | default }
Auto TE FRR is enabled on the outbound interface on the ingress node of the
primary tunnel.
To implement link protection, specify link. If link is not specified, the system
provides only node protection.
By default, after auto TE FRR is enabled globally, all the MPLS TE interfaces
are automatically configured with the mpls te auto-frr default command. To
disable auto TE FRR on some interfaces, run the mpls te auto-frr block
command on these interfaces. Then, these interfaces no longer have auto TE
FRR capability even if auto TE FRR is enabled or is to be re-enabled globally.
After mpls te auto-frr is used in the MPLS view, the mpls te auto-frr default or mpls
te auto-frr node command used on an interface protects only nodes. When the
topology does not meet the requirement to set up an automatic bypass tunnel for
node protection, the penultimate hop (but not other hops) on the primary tunnel
attempts to set up an automatic bypass tunnel for link protection.
----End
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6.15.2 Enabling the TE FRR and Configuring the Auto Bypass
Tunnel Attributes
Context
After TE Auto FRR is enabled, the system automatically sets up a bypass tunnel.
Perform the following configurations on the ingress node of the primary MPLS TE
tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel interface-number
The tunnel interface view of the primary tunnel is displayed.
Step 3 Run mpls te fast-reroute [ bandwidth ]
The TE FRR is enabled.
To guarantee the tunnel bandwidth, you must specify the parameter bandwidth.
Step 4 (Optional) Run mpls te bypass-attributes [ bandwidth bandwidth ] [ priority
setup-priority [ hold-priority ] ]
The attributes of the bypass tunnel are configured.
● The bypass tunnel attributes can be configured only after the mpls te fast-reroute
bandwidth command is run on the primary tunnel.
● The bandwidth of the bypass tunnel cannot be greater than the bandwidth of the
primary tunnel.
● When the attributes of the automatic bypass tunnel are not configured, by default, the
bandwidth of the automatic bypass tunnel is the same as the bandwidth of the primary
tunnel.
● The setup priority of the bypass tunnel cannot be higher than the holding priority. Both
priorities cannot be higher than the priority of the primary tunnel.
● When the bandwidth of the primary tunnel is changed or the FRR is disabled, the
attributes of the bypass tunnel are cleared automatically.
Step 5 Run mpls te commit
The current configuration of the tunnel is committed.
----End
6.15.3 (Optional) Configuring a TE FRR Scanning Timer
Context
A TE FRR-enabled device periodically refreshes the binding between a bypass CRLSP and a primary LSP at a specified interval. The PLR searches for the optimal TE
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bypass CR-LSP and binds it to a primary CR-LSP. A TE FRR scanning timer is set to
determine the interval at which the binding between a bypass CR-LSP and a
primary CR-LSP is refreshed.
Perform the following configurations on the PLR.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls te timer fast-reroute [ weight ]
Set the interval at which the binding between a bypass CR-LSP and a primary CRLSP is refreshed.
By default, the time weight used to calculate the interval is 300. And the actual
interval at which the binding between a bypass CR-LSP and a primary LSP is
refreshed depends on device performance and the maximum number of LSPs that
can be established on the device.
----End
6.15.4 (Optional) Changing the PSB and RSB Timeout
Multiplier
Context
To help allow TE FRR to operate during the RSVP GR process, the timeout
multiplier of the Path State Block (PSB) and Reservation State Block (RSB) can be
set. The setting prevents the situation where information in PSBs and RSBs is
dropped due to a timeout before the GR processes are complete for a large
number of CR-LSPs.
Perform the following configurations on the PLR.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls rsvp-te keep-multiplier keep-multiplier-number
The PSB and RSB timeout multiplier is set.
The default timeout multiplier is 3.
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Setting the timeout multiplier to 5 or greater is recommended for a network where a large
number of CR-LSPs are established and RSVP GR is configured.
----End
6.15.5 (Optional) Configuring Auto Bypass Tunnel ReOptimization
Context
Network changes often cause the changes in optimal paths. Auto Bypass tunnel
re-optimization allows paths to be recalculated at certain intervals for an auto
bypass tunnel. If an optimal path to the same destination is found due to some
reasons, such as the changes in the cost, a new auto bypass tunnel will be set up
over this optimal path. In this manner, network resources are optimized.
Perform the following configurations on the PLR.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls te auto-frr reoptimization [ frequency interval ]
Auto bypass tunnel re-optimization is enabled.
By default, auto bypass tunnel re-optimization is disabled. If re-optimization is
enabled, the default interval at which auto bypass tunnel re-optimization is
performed is 3600 seconds.
Step 4 (Optional) Immediately re-optimize the TE tunnels.
1.
Run return
Return to the user view.
2.
Run mpls te reoptimization
Manual re-optimization is enabled.
After you configure the automatic re-optimization in the tunnel interface
view, you can return to the user view and run the mpls te reoptimization
command to immediately re-optimize the TE tunnels. After you perform the
manual re-optimization, the timer of the automatic re-optimization is reset
and counts again.
----End
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6.15.6 (Optional) Configuring Interworking with a NonHuawei Device
Context
If a non-Huawei device connected to the Huawei device uses the integer mode to
save the bandwidth of FRR objects, configure the Huawei device to save the
bandwidth of FRR objects in integer mode.
Perform the following operations on the PLR connected to the non-Huawei device.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls rsvp-te fast-reroute-bandwidth compatible
The device is configured to save the bandwidth of FRR objects in integer mode.
By default, the bandwidth of FRR objects is saved in the float point mode.
----End
6.15.7 Verifying the Auto TE FRR Configuration
Prerequisites
The configurations of the auto TE FRR function are complete.
Procedure
●
Run the display mpls te tunnel verbose command to check binding
information about the primary tunnel and the auto bypass tunnel.
●
Run the display mpls lsp attribute bypass-inuse { inuse | not-exists | existsnot-used } command to check information about the attribute of a specified
bypass LSP.
●
Run the display mpls lsp attribute bypass-tunnel tunnel-name command to
check information about the attribute of a bypass tunnel.
●
Run the display mpls te tunnel-interface [ tunnel interface-number | autobypass-tunnel [ tunnel-name ] ] command to check detailed information
about the tunnel interface of a specified primary or bypass tunnel.
●
Run the display mpls te tunnel path [ [ [ tunnel-name ] tunnel-name ]
[ lsp-id ingress-lsr-id session-id lsp-id ] | fast-reroute { local-protectionavailable | local-protection-inuse } | lsr-role { ingress | transit | egress } ]
command to check information about paths of a specified primary or bypass
tunnel.
●
Run the display mpls rsvp-te statistics fast-reroute command to check TE
FRR statistics.
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●
6 MPLS TE Configuration
Run the display mpls stale-interface [ interface-index ] [ verbose ]
command to check the information about MPLS interfaces in the Stale state.
----End
6.16 Configuring Association Between TE FRR and CRLSP Backup
After the primary CR-LSP is faulty, the system starts the TE FRR bypass tunnel and
tries to restore the primary CR-LSP the same time it sets up a backup CR-LSP.
Pre-configuration Tasks
Before configuring association between TE FRR and CR-LSP backup, complete the
following tasks:
●
Configure CR-LSP backup (except for the best-effort path) in either hot
standby mode or ordinary backup mode. For details, see 6.13 Configuring
CR-LSP Backup.
●
Configure manual TE FRR or auto TE FRR. For details, see 6.14 Configuring
Manual TE FRR or 6.15 Configuring Auto TE FRR.
Context
Association between TE FRR and CR-LSP backup protects the entire CR-LSP.
Perform the following configurations on the ingress node of the primary MPLS TE
tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel interface-number
The tunnel interface view of the MPLS TE tunnel is displayed.
Step 3 Run mpls te backup frr-in-use
When the primary CR-LSP is faulty (that is, the primary CR-LSP is in FRR-in-use
state), the system starts the bypass CR-LSP and tries to restore the primary CRLSP. At the same time, the system attempts to set up a backup CR-LSP.
Step 4 Run mpls te commit
The tunnel configurations are committed.
----End
Verifying the Configuration
Run the display mpls te tunnel-interface [ tunnel interface-number | autobypass-tunnel [ tunnel-name ] ] command to view information about the tunnel.
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6.17 Configuring a Tunnel Protection Group
A configured protection tunnel can be bound to a working tunnel to form a tunnel
protection group. If the working tunnel fails, traffic switches to the protection
tunnel. The tunnel protection group helps improve tunnel reliability.
Pre-configuration Tasks
Before configuring a tunnel protection group, complete the following tasks:
●
Create a working tunnel. For details, see 6.7 Configuring a Static MPLS TE
Tunnel or 6.8 Configuring a Dynamic MPLS TE Tunnel.
●
Create a protection tunnel. For details, see 6.7 Configuring a Static MPLS TE
Tunnel or 6.8 Configuring a Dynamic MPLS TE Tunnel.
● A TE tunnel protection group enhances reliability of the primary tunnel through
planning. Before configuring a TE tunnel protection group, plan the network. To ensure
better performance of the protection tunnel, the protection tunnel must detour the links
and nodes through which the primary tunnel passes.
● Perform the operation of 6.19 Configuring Static BFD for CR-LSPs or 6.20 Configuring
Dynamic BFD for CR-LSPs to implement fast switching at the millisecond level.
Configuration Procedure
Except that configuring the protection switching trigger mechanism is optional,
other configurations are mandatory.
6.17.1 Creating a Tunnel Protection Group
Context
A configured protection tunnel can be bound to a working tunnel to form a tunnel
protection group. If the working tunnel fails, traffic switches to the protection
tunnel, improving tunnel reliability.
When creating a tunnel protocol group, you can set the switchback delay and a
switchback mode. The switchback modes are classified into revertive and nonrevertive modes. You can set the switchback delay only when the revertive mode is
used.
You can also perform the following steps to modify a tunnel protection group.
Perform the following configurations on the ingress node of the primary MPLS TE
tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
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Step 2 Run interface tunnel interface-number
The tunnel interface view of the primary tunnel is displayed.
Step 3 Run mpls te protection tunnel tunnel-id [ holdoff holdoff-time ] [ mode { nonrevertive | revertive [ wtr wtr-time ] } ]
The working tunnel is added to the protection group.
The following parameters can be configured in this step:
●
tunnel-id specifies the tunnel ID of a protection tunnel.
●
The holdoff time specifies the time between the declaration of signal failure
and the initialization of protection switching. The holdoff time ranges from 0
to 100. The default hold-off time is 0 milliseconds. holdoff-time specifies a
multiplier of 100 milliseconds.
Holdoff-time = 100 milliseconds x holdoff-time
●
non-revertive mode means that traffic does not switch back to a working
tunnel even though a working tunnel recovers.
●
revertive mode means that traffic can switch back to a working tunnel after
the working tunnel recovers.
By default, the tunnel protection group works in revertive mode.
●
Wait to restore (WTR) time is the time elapses before traffic switching is
performed. The WTR time ranges from 0 to 30 minutes. The default WTR time
is 12 minutes. The wtr-time parameter specifies a multiplier of 30 seconds.
WTR time = 30 seconds x wtr-time
If the number of working tunnels in the same tunnel protection group is N, perform Step 2
and Step 3 on each interface with a specific interface-number.
Step 4 Run mpls te commit
The current configuration of the tunnel protection group is committed.
----End
6.17.2 (Optional) Configuring the Protection Switching
Trigger Mechanism
Context
After configuring a tunnel protection group, you can configure a trigger
mechanism of protection switching to force traffic to switch to the primary LSP or
the backup LSP. Alternatively, you can perform switchover manually.
Pay attention to the protection switching mechanism before configuring the
protection switching trigger mechanism.
The device performs protection switching based on the following rules, see Table
6-27. ↑ in this table indicates that the priority level in the upper line is higher than
that in a lower line.
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Table 6-27 Switching rules
Switching Request
Order of
Priority
Description
Clear
Highest
Clears all switching requests initiated
manually, including forcible and manual
switching. A signal failure does not trigger
traffic switching.
Lockout of
protection
↑
Prevents traffic from switching to a
protection tunnel even though a working
tunnel fails.
Forcible switch
↑
Forcibly switches traffic from a working
tunnel to a protection tunnel, irrespective of
whether the protection tunnel functions
properly (unless a higher priority switch
request takes effect).
Signal failure
↑
Automatically triggers protection switching.
Manual switching
↑
Switches traffic from a working tunnel to a
protection tunnel only when the protection
tunnel functions properly or switches traffic
from the protection tunnel to the working
tunnel only when the working tunnel
functions properly.
Wait to restore
↑
Switches traffic from a protection tunnel to a
working tunnel after the working tunnel
recovers after the wait-to-restore (WTR)
timer elapses.
No request
Lowest
There is no switching request.
Perform the following configurations on the ingress node of the primary MPLS TE
tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run interface tunnel interface-number
The tunnel interface view of the primary tunnel is displayed.
Step 3 Select one of the following protection switching trigger methods as required:
●
To forcibly switch traffic from the working tunnel to the protection tunnel, run
mpls te protect-switch force
●
To prevent traffic from switching on the working tunnel, run mpls te protectswitch lock
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●
To switch traffic to the protection tunnel, run mpls te protect-switch manual
●
To cancel the configuration of the protection switching trigger mechanism,
run mpls te protect-switch clear
Step 4 Run mpls te commit
The current configuration is committed.
----End
6.17.3 Verifying the Configuration of a Tunnel Protection
Group
Prerequisites
All configurations of a tunnel protection group are complete.
Procedure
Step 1 Run the display mpls te protection tunnel { all | tunnel-id | interface tunnel
interface-number } [ verbose ] command to check information about a tunnel
protection group.
Step 2 Run the display mpls te protection binding protect-tunnel { tunnel-id |
interface tunnel interface-number } command to check the binding between the
working and protection tunnels.
----End
6.18 Configuring Dynamic BFD for RSVP
When a Layer 2 device exists between a PLR and its downstream neighbors,
configure dynamic BFD for RSVP to detect link faults between RSVP neighboring
nodes.
Pre-configuration Tasks
Before configuring dynamic BFD for RSVP, complete one of the following tasks:
●
Configure a dynamic MPLS TE tunnel. For details, see 6.8 Configuring a
Dynamic MPLS TE Tunnel.
●
Configure manual TE FRR. For details, see 6.14 Configuring Manual TE FRR.
●
Configure auto TE FRR. For details, see 6.15 Configuring Auto TE FRR.
Configuration Procedure
Except that adjusting BFD parameters is optional, other configurations are
mandatory.
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6.18.1 Enabling BFD Globally
Context
To configure dynamic BFD for RSVP, you must enable BFD on both ends of RSVP
neighbors.
Perform the following configurations on the two RSVP neighboring nodes with a
Layer 2 device exists between them.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run bfd
BFD is enabled globally.
----End
6.18.2 Enabling BFD for RSVP
Context
Enabling BFD for RSVP in the following manners:
●
Enabling BFD for RSVP Globally
Enable BFD for RSVP globally when a large number of RSVP-enabled
interfaces of the local node need to be enabled with BFD for RSVP.
●
Enabling BFD for RSVP on the RSVP Interface
Enable BFD for RSVP on the RSVP interface when a small number of RSVPenabled interfaces of the local node need to be enabled with BFD for RSVP.
Perform the following configurations on the two RSVP neighboring nodes with a
Layer 2 device exists between them.
Procedure
●
Enable BFD for RSVP globally.
a.
Run system-view
The system view is displayed.
b.
Run mpls
The MPLS view is displayed.
c.
Run mpls rsvp-te bfd all-interfaces enable
BFD for RSVP is enabled globally.
After this command is run in the MPLS view, BFD for RSVP is enabled on
all RSVP interfaces except the interfaces with BFD for RSVP that are
blocked.
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6 MPLS TE Configuration
(Optional) Disable BFD for RSVP on the RSVP interfaces that does not
need to be enabled with BFD for RSVP.
i.
Run quit
Return to the system view.
ii.
Run interface interface-type interface-number
The view of the RSVP-TE-enabled interface is displayed.
iii.
On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
iv.
Run mpls rsvp-te bfd block
BFD for RSVP is disabled on the interface.
●
Enable BFD for RSVP on the RSVP interface.
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The view of the RSVP-TE-enabled interface is displayed.
c.
Run mpls rsvp-te bfd enable
BFD for RSVP is enabled on the RSVP interface.
----End
6.18.3 (Optional) Adjusting BFD Parameters
Context
BFD parameters are adjusted on the ingress node of a TE tunnel using either of
the following modes:
●
Adjusting Global BFD Parameters
Adjust global BFD parameters when a large number of RSVP-enabled
interfaces of the local node use the same BFD parameters.
●
Adjusting BFD Parameters on an RSVP Interface
Adjust global BFD parameters on an RSVP interface when certain RSVPenabled interfaces of the local node need to use BFD parameters different
from global BFD parameters.
Perform the following configurations on the two RSVP neighboring nodes with a
Layer 2 device exists between them.
Procedure
●
Adjust global BFD parameters globally.
a.
Run system-view
The system view is displayed.
b.
Run mpls
The MPLS view is displayed.
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6 MPLS TE Configuration
Run mpls rsvp-te bfd all-interfaces { min-tx-interval tx-interval | minrx-interval rx-interval | detect-multiplier multiplier } *
BFD parameters are set globally.
Parameters are described as follows:
n
tx-interval indicates the Desired Min Tx Interval (DMTI), that is, the
desired minimum interval for the local end sending BFD control
packets.
n
rx-interval indicates the Required Min Rx Interval (RMRI), that is, the
supported minimum interval for the local end receiving BFD control
packets.
n
multiplier indicates the BFD detection multiplier.
BFD detection parameters that take effect on the local node may be
different from the configured parameters:
●
n
Actual local sending interval = MAX { Locally-configured DMTI,
Remotely-configured RMRI }
n
Actual local receiving interval = MAX { Remotely-configured DMTI,
Locally-configured RMRI }
n
Actual local detection interval = Actual local receiving interval x
Configured remote detection multiplier
Adjust BFD parameters on an RSVP interface.
a.
Run system-view
The system view is displayed.
b.
Run interface interface-type interface-number
The view of the RSVP-TE-enabled interface is displayed.
c.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between
Layer 2 and Layer 3 modes.
d.
Run mpls rsvp-te bfd { min-tx-interval tx-interval | min-rx-interval rxinterval | detect-multiplier multiplier } *
BFD parameters on the RSVP interface are adjusted.
----End
6.18.4 Verifying the Configuration of Dynamic BFD for RSVP
Prerequisites
The configurations of dynamic BFD for RSVP are complete.
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Procedure
●
Run the display mpls rsvp-te bfd session { all | interface interface-type
interface-number | peer ip-address } [ verbose ] command to check
information about the BFD for RSVP session.
●
Run the display mpls rsvp-te command to check the RSVP-TE configuration.
●
Run the display mpls rsvp-te interface [ interface-type interface-number ]
command to check the RSVP-TE configuration on the interface.
●
Run the display mpls rsvp-te peer [ interface interface-type interfacenumber ] command to check information about the RSVP neighbor.
●
Run the display mpls rsvp-te statistics { global | interface [ interface-type
interface-number ] } command to check RSVP-TE statistics.
----End
6.19 Configuring Static BFD for CR-LSPs
Static BFD for CR-LSPs can rapidly detect a fault on a CR-LSP and notifies the
forwarding plane, ensuring fast traffic switchover.
Pre-configuration Tasks
Before configuring static BFD for CR-LSPs, complete one of the following tasks:
●
Configure a static MPLS TE tunnel. For details, see 6.7 Configuring a Static
MPLS TE Tunnel.
●
Configure a dynamic MPLS TE tunnel. For details, see 6.8 Configuring a
Dynamic MPLS TE Tunnel.
●
Configure CR-LSP backup. For details, see 6.13 Configuring CR-LSP Backup.
●
Configure a tunnel protection group. For details, see 6.17 Configuring a
Tunnel Protection Group.
Configuration Procedure
The following configurations are mandatory.
6.19.1 Enabling BFD Globally
Context
To configure static BFD for CR-LSP, you must enable BFD globally on the ingress
node and the egress node of a tunnel.
Perform the following configurations on the ingress and egress nodes of an MPLS
TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
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Step 2 Run bfd
BFD is enabled globally.
----End
6.19.2 Configuring BFD Parameters on the Ingress Node of the
Tunnel
Context
The BFD parameters configured on the ingress node include the local and remote
discriminators, local intervals at which BFD packets are sent and received, and BFD
detection multiplier, which determine the establishment of a BFD session.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run bfd cfg-name bind mpls-te interface tunnel interface-number te-lsp
[ backup ]
BFD is configured to detect the primary or backup CR-LSP bound to a specified
tunnel.
The parameter backup means that backup CR-LSPs are to be checked.
Step 3 Run discriminator local discr-value
The local discriminator is set.
Step 4 Run discriminator remote discr-value
The remote discriminator is set.
Step 5 (Optional) Run min-tx-interval interval
The local interval at which BFD packets are sent is set.
Step 6 (Optional) Run min-rx-interval interval
The local interval at which BFD packets are received is set.
Step 7 (Optional) Run detect-multiplier multiplier
The local detection multiplier is adjusted.
By default, the local detection multiplier is 3.
Actual local sending interval = MAX { Configured local sending interval,
Configured remote receiving interval }
Actual local receiving interval = MAX { Configured remote sending interval,
Configured local receiving interval }
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Actual local detection interval = Actual local receiving interval x Configured
remote detection multiplier
For example:
●
The local sending and receiving intervals are set to 200 ms and 300 ms
respectively and the detection multiplier is set to 4.
●
The remote sending and receiving intervals are set to 100 ms and 600 ms
respectively and the detection multiplier is set to 5.
Then,
●
Actual local sending interval = MAX {200 ms, 600 ms} = 600 ms; Actual local
receiving interval = MAX {100 ms, 300 ms} = 300 ms; Actual local detection
interval is 300 ms x 5 = 1500 ms.
●
Actual remote sending interval = MAX {100 ms, 300 ms} = 300 ms; Actual
remote receiving interval = MAX {200 ms, 600 ms} = 600 ms; Actual remote
detection interval is 600 ms x 4 = 2400 ms.
Step 8 Run process-pst
The system is enabled to modify the port status table (PST) when the BFD session
status changes.
When the BFD status changes, BFD notifies the application of the change,
triggering a fast switchover between the primary and backup CR-LSPs.
Step 9 Run notify neighbor-down
A BFD session is configured to notify the upper layer protocol when the BFD
session detects a neighbor Down event.
In most cases, when you use a BFD session to detect link faults, the BFD session
notifies the upper layer protocol of a link fault in the following scenarios:
●
When the BFD detection time expires, the BFD session notifies the upper layer
protocol. BFD sessions must be configured on both ends. If the BFD session on
the local end does not receive any BFD packets from the remote end within
the detection time, the BFD session on the local end concludes that the link
fails and notifies the upper layer protocol of the link fault.
●
When a BFD session detects a neighbor Down event, the BFD session notifies
the upper layer protocol. If the BFD session on the local end detects a
neighbor Down event within the detection time, the BFD session on the local
end directly notifies the upper layer protocol of the neighbor Down event.
When you use a BFD session to detect faults on an LSP, you need only be
concerned about whether a fault occurs on the link from the local end to remote
end. In this situation, run the notify neighbor-down command to configure the
BFD session to notify the upper layer protocol only when the BFD session detects
a neighbor Down event. This configuration prevents the BFD session from
notifying the upper layer protocol when the BFD detection time expires and
ensures that services are not interrupted.
Step 10 Run commit
The current configuration is committed.
----End
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6.19.3 Configuring BFD Parameters on the Egress Node of the
Tunnel
Context
The BFD parameters configured on the egress node include the local and remote
discriminators, local intervals at which BFD packets are sent and received, and BFD
detection multiplier, which determine the establishment of a BFD session.
Perform the following configurations on the egress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Configure a reverse tunnel to inform the ingress node of a fault if the fault occurs.
The reverse tunnel can be the IP link, LSP, or TE tunnel. To ensure that the forward
and reverse paths are over the same link, a CR-LSP is preferentially selected to
notify the ingress node of an LSP fault. Run the following commands as required.
●
For an IP link, run bfd session-name bind peer-ip ip-address [ vpn-instance
vpn-name ] [ interface interface-type interface-number] [ source-ip ipaddress ]
●
For an LDP LSP, run bfd session-name bind ldp-lsp peer-ip ip-address
nexthop ip-address [ interface interface-type interface-number ]
●
For a static LSP, run bfd session-name bind static-lsp lsp-name
●
For a CR-LSP, run bfd session-name bind mpls-te interface tunnel interfacenumber te-lsp [ backup ]
●
For a TE tunnel, run bfd session-name bind mpls-te interface tunnel
interface-number
When an IP link is used as the reverse tunnel, you do not need to perform steps 8 and 9.
Step 3 Run discriminator local discr-value
The local discriminator is set.
Step 4 Run discriminator remote discr-value
The remote discriminator is set.
Step 5 (Optional) Run min-tx-interval interval
The local interval at which BFD packets are sent is set.
Step 6 (Optional) Run min-rx-interval interval
The local interval at which BFD packets are received is set.
Step 7 (Optional) Run detect-multiplier multiplier
The local detection multiplier is adjusted.
By default, the local detection multiplier is 3.
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Actual local sending interval = MAX { Configured local sending interval,
Configured remote receiving interval }
Actual local receiving interval = MAX { Configured remote sending interval,
Configured local receiving interval }
Actual local detection interval = Actual local receiving interval x Configured
remote detection multiplier
For example:
●
The local sending and receiving intervals are set to 200 ms and 300 ms
respectively and the detection multiplier is set to 4.
●
The remote sending and receiving intervals are set to 100 ms and 600 ms
respectively and the detection multiplier is set to 5.
Then,
●
Actual local sending interval = MAX {200 ms, 600 ms} = 600 ms; Actual local
receiving interval = MAX {100 ms, 300 ms} = 300 ms; Actual local detection
interval is 300 ms x 5 = 1500 ms.
●
Actual remote sending interval = MAX {100 ms, 300 ms} = 300 ms; Actual
remote receiving interval = MAX {200 ms, 600 ms} = 600 ms; Actual remote
detection interval is 600 ms x 4 = 2400 ms.
Step 8 (Optional) Run process-pst
The system is enabled to modify the port status table (PST) when the BFD session
status changes.
If an LSP or a TE tunnel is used as a reverse tunnel to notify the ingress node of a
fault, you can run this command to allow the reverse tunnel to switch traffic if the
BFD session goes Down. If a single-hop IP link is used as a reverse tunnel, this
command can be configured. Because the process-pst command can be only
configured for BFD single-link detection.
Step 9 Run notify neighbor-down
A BFD session is configured to notify the upper layer protocol when the BFD
session detects a neighbor Down event.
In most cases, when you use a BFD session to detect link faults, the BFD session
notifies the upper layer protocol of a link fault in the following scenarios:
●
When the BFD detection time expires, the BFD session notifies the upper layer
protocol. BFD sessions must be configured on both ends. If the BFD session on
the local end does not receive any BFD packets from the remote end within
the detection time, the BFD session on the local end concludes that the link
fails and notifies the upper layer protocol of the link fault.
●
When a BFD session detects a neighbor Down event, the BFD session notifies
the upper layer protocol. If the BFD session on the local end detects a
neighbor Down event within the detection time, the BFD session on the local
end directly notifies the upper layer protocol of the neighbor Down event.
When you use a BFD session to detect faults on an LSP, you need only be
concerned about whether a fault occurs on the link from the local end to remote
end. In this situation, run the notify neighbor-down command to configure the
BFD session to notify the upper layer protocol only when the BFD session detects
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a neighbor Down event. This configuration prevents the BFD session from
notifying the upper layer protocol when the BFD detection time expires and
ensures that services are not interrupted.
Step 10 Run commit
The current configuration is committed.
----End
6.19.4 Verifying the Configuration of Static BFD for CR-LSPs
Prerequisites
The configurations of static BFD for CR-LSPs are complete.
Procedure
●
Run the display bfd configuration mpls-te interface tunnel interfacenumber te-lsp [ verbose ] command to check BFD configurations on the
ingress.
●
Run the following commands to check BFD configurations on the egress:
–
Run the display bfd configuration all [ for-ip | for-lsp | for-te ]
[ verbose ] command to check all BFD configurations.
–
●
●
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Run the display bfd configuration static [ for-ip | for-lsp | for-te | name
cfg-name ] [ verbose ] command to check the static BFD configurations.
– Run the display bfd configuration peer-ip peer-ip [ vpn-instance vpninstance-name ] [ verbose ] command to check the configurations of
BFD with the reverse path being an IP link.
– Run the display bfd configuration static-lsp lsp-name [ verbose ]
command to check the configurations of BFD with the reverse path being
a static LSP.
– Run the display bfd configuration ldp-lsp peer-ip peer-ip nexthop
nexthop-address [ interface interface-type interface-number ]
[ verbose ] command to check the configurations of BFD with the
backward channel being an LDP LSP.
– Run the display bfd configuration mpls-te interface tunnel interfacenumber te-lsp [ verbose ] command to check the configurations of BFD
with the backward channel being a CR-LSP.
– Run the display bfd configuration mpls-te interface tunnel interfacenumber [ verbose ] command to check the configurations of BFD with
the backward channel being a TE tunnel.
Run the display bfd session mpls-te interface tunnel interface-number telsp [ verbose ] command to check BFD session configurations on the ingress.
Run the following commands to check BFD session configurations on the
egress:
–
Run the display bfd session all [ for-ip | for-lsp | for-te ] [ verbose ]
command to check all the BFD configurations.
–
Run the display bfd session static [ for-ip | for-lsp | for-te ] [ verbose ]
command to check the static BFD configurations.
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–
Run the display bfd session peer-ip peer-ip [ vpn-instance vpn-instancename ] [ verbose ] command to check the configurations of BFD with
the backward channel being an IP link.
–
Run the display bfd session static-lsp lsp-name [ verbose ] command to
check the configurations of BFD with the backward channel being a static
LSP.
–
Run the display bfd session ldp-lsp peer-ip peer-ip nexthop nexthopaddress [ interface interface-type interface-number ] [ verbose ]
command to check the configurations of BFD with the backward channel
being an LDP LSP.
–
Run the display bfd session mpls-te interface tunnel interface-number
te-lsp [ verbose ] command to check the configurations of BFD with the
backward channel being a CR-LSP.
–
Run the display bfd session mpls-te interface tunnel interface-number
[ verbose ] command to check the configurations of BFD with the
backward channel being a TE tunnel.
Run the following command to check BFD statistics:
–
Run the display bfd statistics session all [ for-ip | for-lsp | for-te ]
command to check all BFD session statistics.
–
Run the display bfd statistics session peer-ip peer-ip [ vpn-instance
vpn-instance-name ] command to check statistics about the BFD session
that detects faults in the IP link.
–
Run the display bfd statistics session static-lsp lsp-name command to
check statistics about the BFD session that detects faults in the static LSP.
–
Run the display bfd statistics session ldp-lsp peer-ip peer-ip nexthop
nexthop-address [ interface interface-type interface-number ] command
to check statistics of the BFD session that detects faults in the LDP LSP.
–
Run the display bfd statistics session mpls-te interface tunnel
interface-number te-lsp command to check statistics about the BFD
session that detects faults in the CR-LSP.
–
Run the display bfd statistics session mpls-te interface tunnel
interface-number command to check statistics on BFD sessions for TE
tunnels.
----End
6.20 Configuring Dynamic BFD for CR-LSPs
Compared with static BFD for CR-LSPs, dynamic BFD for CR-LSPs simplifies the
configuration and reduces manual operations.
Pre-configuration Tasks
Before configuring dynamic BFD for CR-LSPs, complete one of the following tasks:
●
Configure a static MPLS TE tunnel. For details, see 6.7 Configuring a Static
MPLS TE Tunnel.
●
Configure a dynamic MPLS TE tunnel. For details, see 6.8 Configuring a
Dynamic MPLS TE Tunnel.
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●
Configure CR-LSP backup. For details, see 6.13 Configuring CR-LSP Backup.
●
Configure a tunnel protection group. For details, see 6.17 Configuring a
Tunnel Protection Group.
Configuration Procedure
Except that adjusting BFD parameters is optional, other configurations are
mandatory.
6.20.1 Enabling BFD Globally
Context
To configure dynamic BFD for CR-LSP, enable BFD globally on the ingress node
and the egress node of a tunnel.
Perform the following configurations on the ingress and egress nodes of an MPLS
TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run bfd
BFD is enabled globally.
----End
6.20.2 Enabling the Capability of Dynamically Creating BFD
Sessions on the Ingress
Context
Enabling the capability of dynamically creating BFD sessions on a TE tunnel can be
implemented in either of the following methods:
●
Enabling MPLS TE BFD Globally when BFD sessions need to be created
automatically on a large number of TE tunnels of the ingress node
●
Enabling MPLS TE BFD on the Tunnel Interface when BFD sessions need to
be created automatically on a small number of TE tunnels of the ingress node
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
●
Enable MPLS TE BFD globally.
a.
Run system-view
The system view is displayed.
b.
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Run mpls
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The MPLS view is displayed.
c.
Run mpls te bfd enable
The capability of dynamically creating BFD sessions is enabled on the TE
tunnel.
After this command is run in the MPLS view, dynamic BFD for TE is
enabled on all the tunnel interfaces, excluding the interfaces on which
dynamic BFD for TE are blocked.
d.
(Optional) Block the capability of dynamically creating BFD sessions for
TE on the tunnel interfaces of the TE tunnels that do not need dynamic
BFD for TE.
i.
Run quit
Return to the system view.
ii.
Run interface tunnel interface-number
The TE tunnel interface view is displayed.
iii.
Run mpls te bfd block
The capability of dynamically creating BFD sessions on the tunnel
interface is blocked.
iv.
Run mpls te commit
The current configuration on this tunnel interface is committed.
●
Enable MPLS TE BFD on a tunnel interface.
a.
Run system-view
The system view is displayed.
b.
Run interface tunnel interface-number
The TE tunnel interface view is displayed.
c.
Run mpls te bfd enable
The capability of dynamically creating BFD sessions is enabled on the TE
tunnel.
The command configured in the tunnel interface view takes effect only
on the current tunnel interface.
d.
Run mpls te commit
The configuration of the TE tunnel is committed.
----End
6.20.3 Enabling the Capability of Passively Creating BFD
Sessions on the Egress
Context
On a unidirectional LSP, creating a BFD session on the active role (ingress node)
triggers the sending of LSP ping request messages to the passive role (egress
node). Only after the passive role receives the ping packets, a BFD session can be
automatically set up.
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Perform the following configurations on the egress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run bfd
The BFD view is displayed.
Step 3 Run mpls-passive
The capability of passively creating BFD sessions is enabled.
After this command is run, a BFD session can be created only after the egress
receives an LSP Ping request containing a BFD TLV from the ingress.
----End
6.20.4 (Optional) Adjusting BFD Parameters
Context
BFD parameters are adjusted on the ingress node of a TE tunnel using either of
the following modes:
●
Adjusting Global BFD Parameters when a large number of TE tunnels on the
ingress node use the same BFD parameters
●
Adjusting BFD Parameters on an Interface when certain TE tunnels on the
ingress node need to use BFD parameters different from global BFD
parameters
Actual local sending interval = MAX { Configured local sending interval,
Configured remote receiving interval }
Actual local receiving interval = MAX { Configured remote sending interval,
Configured local receiving interval }
Actual local detection interval = Actual local receiving interval x Configured
remote detection multiplier
On the egress node of the TE tunnel enabled with the capability of passively
creating BFD sessions, the default values of the receiving interval, sending interval
and detection multiplier cannot be adjusted. The default values of these three
parameters are the minimum configurable values on the egress node. Therefore,
the BFD detection interval on the ingress and that on the egress node of a CR-LSP
are as follows:
●
Actual detection interval on the ingress = Configured receiving interval on the
ingress node x 3
●
Actual detection interval on the egress = Configured sending interval on the
ingress x Configured detection multiplier on the ingress node
Perform the following configurations on the ingress node of an MPLS TE tunnel.
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Procedure
●
Adjust global BFD parameters.
a.
Run system-view
The system view is displayed.
b.
Run mpls
The MPLS view is displayed.
c.
Run mpls te bfd { min-tx-interval tx-interval | min-rx-interval rxinterval | detect-multiplier multiplier } *
BFD time parameters are adjusted globally.
●
Adjust BFD parameters on the tunnel interface.
a.
Run system-view
The system view is displayed.
b.
Run interface tunnel interface-number
The TE tunnel interface view is displayed.
c.
Run mpls te bfd { min-tx-interval tx-interval | min-rx-interval rxinterval | detect-multiplier multiplier } *
BFD time parameters are adjusted.
If min-tx-interval tx-interval configured on a local end is different from
min-rx-interval rx-interval configured on a remote end, the larger value
takes effect.
The detect-multiplier multiplier value configured on the remote end
takes effect.
d.
Run mpls te commit
The current configurations of the TE tunnel interface are committed.
----End
6.20.5 Verifying the Configuration of Dynamic BFD for CRLSPs
Prerequisites
The configurations of dynamic BFD for CR-LSPs are complete.
Procedure
●
Run the display bfd configuration dynamic [ verbose ] command to check
the configuration of dynamic BFD on the ingress.
●
Run the display bfd configuration passive-dynamic [ peer-ip peer-ip
remote-discriminator discriminator ] [ verbose ] command to check the
configuration of dynamic BFD on the egress.
●
Run the display bfd session dynamic [ verbose ] command to check
information about the BFD session on the ingress.
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●
Run the display bfd session passive-dynamic [ peer-ip peer-ip remotediscriminator remote-discr-value ] [ verbose ] command to check
information about the BFD session passively created on the egress.
●
Check the BFD statistics.
●
–
Run the display bfd statistics command to check statistics about all BFD
sessions.
–
Run the display bfd statistics session dynamic command to check
statistics about dynamic BFD sessions.
Run the display mpls bfd session [ fec fec-address | monitor | nexthop ipaddress | outgoing-interface interface-type interface-number | statistics |
verbose ] or display mpls bfd session protocol { cr-static | rsvp-te } [ lsp-id
ingress-lsr-id session-id lsp-id [ verbose ] ] command to check information
about BFD sessions.
----End
6.21 Configuring Static BFD for TE Tunnels
Static BFD for TE allows applications such as VPN FRR and VLL FRR to fast switch
traffic if the primary tunnel fails, preventing service interruption.
Pre-configuration Tasks
Before configuring static BFD for TE tunnels, complete one of the following tasks:
●
Configure a static MPLS TE tunnel. For details, see 6.7 Configuring a Static
MPLS TE Tunnel.
●
Configure a dynamic MPLS TE tunnel. For details, see 6.8 Configuring a
Dynamic MPLS TE Tunnel.
●
Configure a tunnel protection group. For details, see 6.17 Configuring a
Tunnel Protection Group.
Configuration Procedure
The following configurations are mandatory.
6.21.1 Enabling BFD Globally
Context
To configure static BFD for TE, enable BFD globally on the ingress and egress
nodes of a tunnel.
Perform the following configurations on the ingress and egress nodes of an MPLS
TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
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Step 2 Run bfd
BFD is enabled globally.
----End
6.21.2 Configuring BFD Parameters on the Ingress Node of the
Tunnel
Context
The BFD parameters configured on the ingress node include the local and remote
discriminators, local intervals at which BFD packets are sent and received, and BFD
detection multiplier, which determine the establishment of a BFD session.
Perform the following configurations on the ingress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run bfd cfg-name bind mpls-te interface tunnel interface-number
BFD is configured to detect faults in a specified tunnel.
If the status of the tunnel to be checked is Down, the BFD session cannot be set up.
Step 3 Run discriminator local discr-value
The local discriminator is set.
Step 4 Run discriminator remote discr-value
The remote discriminator is set.
Step 5 (Optional) Run min-tx-interval interval
The local interval at which BFD packets are sent is set.
Step 6 (Optional) Run min-rx-interval interval
The local interval at which BFD packets are received is set.
Step 7 (Optional) Run detect-multiplier multiplier
The local detection multiplier is adjusted.
By default, the local detection multiplier is 3.
Actual local sending interval = MAX { Configured local sending interval,
Configured remote receiving interval }
Actual local receiving interval = MAX { Configured remote sending interval,
Configured local receiving interval }
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Actual local detection interval = Actual local receiving interval x Configured
remote detection multiplier
For example:
●
The local sending and receiving intervals are set to 200 ms and 300 ms
respectively and the detection multiplier is set to 4.
●
The remote sending and receiving intervals are set to 100 ms and 600 ms
respectively and the detection multiplier is set to 5.
Then,
●
Actual local sending interval = MAX {200 ms, 600 ms} = 600 ms; Actual local
receiving interval = MAX {100 ms, 300 ms} = 300 ms; Actual local detection
interval is 300 ms x 5 = 1500 ms.
●
Actual remote sending interval = MAX {100 ms, 300 ms} = 300 ms; Actual
remote receiving interval = MAX {200 ms, 600 ms} = 600 ms; Actual remote
detection interval is 600 ms x 4 = 2400 ms.
Step 8 Run process-pst
The system is enabled to modify the port status table (PST) when the BFD session
status changes.
When the BFD status changes, BFD notifies the application of the change,
triggering a fast switchover between TE tunnels.
Step 9 Run notify neighbor-down
A BFD session is configured to notify the upper layer protocol when the BFD
session detects a neighbor Down event.
In most cases, when you use a BFD session to detect link faults, the BFD session
notifies the upper layer protocol of a link fault in the following scenarios:
●
When the BFD detection time expires, the BFD session notifies the upper layer
protocol. BFD sessions must be configured on both ends. If the BFD session on
the local end does not receive any BFD packets from the remote end within
the detection time, the BFD session on the local end concludes that the link
fails and notifies the upper layer protocol of the link fault.
●
When a BFD session detects a neighbor Down event, the BFD session notifies
the upper layer protocol. If the BFD session on the local end detects a
neighbor Down event within the detection time, the BFD session on the local
end directly notifies the upper layer protocol of the neighbor Down event.
When you use a BFD session to detect faults on an LSP, you need only be
concerned about whether a fault occurs on the link from the local end to remote
end. In this situation, run the notify neighbor-down command to configure the
BFD session to notify the upper layer protocol only when the BFD session detects
a neighbor Down event. This configuration prevents the BFD session from
notifying the upper layer protocol when the BFD detection time expires and
ensures that services are not interrupted.
Step 10 Run commit
The current configuration is committed.
----End
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6.21.3 Configuring BFD Parameters on the Egress Node of the
Tunnel
Context
The BFD parameters configured on the egress node include the local and remote
discriminators, local intervals at which BFD packets are sent and received, and BFD
detection multiplier, which determine the establishment of a BFD session.
Perform the following configurations on the egress node of an MPLS TE tunnel.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Configure a reverse tunnel to inform the ingress node of a fault if the fault occurs.
The reverse tunnel can be the IP link, LSP, or TE tunnel. To ensure that the forward
and reverse paths are over the same link, a TE tunnel is preferentially selected to
notify the ingress node of an LSP fault. Run the following commands as required.
●
For an IP link, run bfd session-name bind peer-ip ip-address [ vpn-instance
vpn-name ] [ interface interface-type interface-number] [ source-ip ipaddress ]
●
For an LDP LSP, run bfd session-name bind ldp-lsp peer-ip ip-address
nexthop ip-address [ interface interface-type interface-number ]
●
For a static LSP, run bfd session-name bind static-lsp lsp-name
●
For a TE tunnel, run bfd session-name bind mpls-te interface tunnel
interface-number
When an IP link is used as the reverse tunnel, you do not need to perform steps 8 and 9.
Step 3 Run discriminator local discr-value
The local discriminator is set.
Step 4 Run discriminator remote discr-value
The remote discriminator is set.
Step 5 (Optional) Run min-tx-interval interval
The local interval at which BFD packets are sent is set.
Step 6 (Optional) Run min-rx-interval interval
The local interval at which BFD packets are received is set.
Step 7 (Optional) Run detect-multiplier multiplier
The local detection multiplier is adjusted.
By default, the local detection multiplier is 3.
Actual local sending interval = MAX { Configured local sending interval,
Configured remote receiving interval }
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Actual local receiving interval = MAX { Configured remote sending interval,
Configured local receiving interval }
Actual local detection interval = Actual local receiving interval x Configured
remote detection multiplier
For example:
●
The local sending and receiving intervals are set to 200 ms and 300 ms
respectively and the detection multiplier is set to 4.
●
The remote sending and receiving intervals are set to 100 ms and 600 ms
respectively and the detection multiplier is set to 5.
Then,
●
Actual local sending interval = MAX {200 ms, 600 ms} = 600 ms; Actual local
receiving interval = MAX {100 ms, 300 ms} = 300 ms; Actual local detection
interval is 300 ms x 5 = 1500 ms.
●
Actual remote sending interval = MAX {100 ms, 300 ms} = 300 ms; Actual
remote receiving interval = MAX {200 ms, 600 ms} = 600 ms; Actual remote
detection interval is 600 ms x 4 = 2400 ms.
Step 8 (Optional) Run process-pst
The system is enabled to modify the port status table (PST) when the BFD session
status changes.
If an LSP or a TE tunnel is used as a reverse tunnel to notify the ingress node of a
fault, you can run this command to allow the reverse tunnel to switch traffic if the
BFD session goes Down. If a single-hop IP link is used as a reverse tunnel, this
command can be configured. Because the process-pst command can be only
configured for BFD single-link detection.
Step 9 Run notify neighbor-down
A BFD session is configured to notify the upper layer protocol when the BFD
session detects a neighbor Down event.
In most cases, when you use a BFD session to detect link faults, the BFD session
notifies the upper layer protocol of a link fault in the following scenarios:
●
When the BFD detection time expires, the BFD session notifies the upper layer
protocol. BFD sessions must be configured on both ends. If the BFD session on
the local end does not receive any BFD packets from the remote end within
the detection time, the BFD session on the local end concludes that the link
fails and notifies the upper layer protocol of the link fault.
●
When a BFD session detects a neighbor Down event, the BFD session notifies
the upper layer protocol. If the BFD session on the local end detects a
neighbor Down event within the detection time, the BFD session on the local
end directly notifies the upper layer protocol of the neighbor Down event.
When you use a BFD session to detect faults on an LSP, you need only be
concerned about whether a fault occurs on the link from the local end to remote
end. In this situation, run the notify neighbor-down command to configure the
BFD session to notify the upper layer protocol only when the BFD session detects
a neighbor Down event. This configuration prevents the BFD session from
notifying the upper layer protocol when the BFD detection time expires and
ensures that services are not interrupted.
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Step 10 Run commit
The current configuration is committed.
----End
6.21.4 Verifying the Configuration of Static BFD for TE
Tunnels
Prerequisites
The configurations of static BFD for TE tunnels are complete.
Procedure
●
Run the display bfd configuration mpls-te interface tunnel interfacenumber [ verbose ] command to check BFD configurations on the ingress.
●
Run the following commands to check BFD configurations on the egress:
–
Run the display bfd configuration all [ for-ip | for-lsp | for-te ]
[ verbose ] command to check all BFD configurations.
–
Run the display bfd configuration static [ for-ip | for-lsp | for-te | name
cfg-name ] [ verbose ] command to check the static BFD configurations.
–
Run the display bfd configuration peer-ip peer-ip [ vpn-instance vpninstance-name ] [ verbose ] command to check the configurations of
BFD with the reverse path being an IP link.
–
Run the display bfd configuration static-lsp lsp-name [ verbose ]
command to check the configurations of BFD with the reverse path being
a static LSP.
–
Run the display bfd configuration ldp-lsp peer-ip peer-ip nexthop
nexthop-address [ interface interface-type interface-number ]
[ verbose ] command to check the configurations of BFD with the
backward channel being an LDP LSP.
–
Run the display bfd configuration mpls-te interface tunnel interfacenumber te-lsp [ verbose ] command to check the configurations of BFD
with the backward channel being a CR-LSP.
–
Run the display bfd configuration mpls-te interface tunnel interfacenumber [ verbose ] command to check the configurations of BFD with
the backward channel being a TE tunnel.
●
Run the display bfd session mpls-te interface tunnel interface-number
[ verbose ] command to check BFD session configurations on the ingress.
●
Run the following commands to check BFD session configurations on the
egress:
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–
Run the display bfd session all [ for-ip | for-lsp | for-te ] [ verbose ]
command to check all the BFD configurations.
–
Run the display bfd session static [ for-ip | for-lsp | for-te ] [ verbose ]
command to check the static BFD configurations.
–
Run the display bfd session peer-ip peer-ip [ vpn-instance vpn-instancename ] [ verbose ] command to check the configurations of BFD with
the backward channel being an IP link.
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–
6 MPLS TE Configuration
Run the display bfd session static-lsp lsp-name [ verbose ] command to
check the configurations of BFD with the backward channel being a static
LSP.
Run the display bfd session ldp-lsp peer-ip peer-ip nexthop nexthopaddress [ interface interface-type interface-number ] [ verbose ]
command to check the configurations of BFD with the backward channel
being an LDP LSP.
– Run the display bfd session mpls-te interface tunnel interface-number
te-lsp [ verbose ] command to check the configurations of BFD with the
backward channel being a CR-LSP.
– Run the display bfd session mpls-te interface tunnel interface-number
[ verbose ] command to check the configurations of BFD with the
backward channel being a TE tunnel.
Run the following command to check BFD statistics:
–
●
–
Run the display bfd statistics session all [ for-ip | for-lsp | for-te ]
command to check all BFD session statistics.
–
Run the display bfd statistics session peer-ip peer-ip [ vpn-instance
vpn-instance-name ] command to check statistics about the BFD session
that detects faults in the IP link.
–
Run the display bfd statistics session static-lsp lsp-name command to
check statistics about the BFD session that detects faults in the static LSP.
–
Run the display bfd statistics session ldp-lsp peer-ip peer-ip nexthop
nexthop-address [ interface interface-type interface-number ] command
to check statistics of the BFD session that detects faults in the LDP LSP.
Run the display bfd statistics session mpls-te interface tunnel
interface-number te-lsp command to check statistics about the BFD
session that detects faults in the CR-LSP.
Run the display bfd statistics session mpls-te interface tunnel
interface-number command to check statistics on BFD sessions for TE
tunnels.
–
–
----End
6.22 Configuring RSVP GR
RSVP GR prevents service interruptions during an active/standby switchover and
allows a dynamic CR-LSP to be restored.
Pre-configuration Tasks
Before configuring RSVP GR, complete the following tasks:
●
Configure a dynamic MPLS TE tunnel. For details, see 6.8 Configuring a
Dynamic MPLS TE Tunnel.
●
Configure IS-IS GR or OSPF GR on each LSR.
Configuration Procedure
Enabling the RSVP GR support function and modifying the basic time and
configuring Hello sessions between RSVP GR nodes are optional.
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6.22.1 Enabling the RSVP Hello Extension Function
Context
By configuring the RSVP Hello extension, you can enable a device to quickly check
reachability between RSVP nodes.
Perform the following configurations on a GR node and its neighboring nodes.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls rsvp-te hello
The RSVP Hello extension function is enabled globally.
Step 4 Run quit
The system view is displayed.
Step 5 Run interface interface-type interface-number
The RSVP-TE interface view is displayed.
Step 6 (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720HI, S5720EI, S6720EI, and S6720S-EI support switching between Layer 2 and
Layer 3 modes.
Step 7 Run mpls rsvp-te hello
The RSVP Hello extension function is enabled on the interface.
By default, although the RSVP Hello extension function has been enabled globally,
it is disabled on RSVP-enabled interfaces.
----End
6.22.2 Enabling RSVP GR
Context
RSVP GR prevents service interruptions during an active/standby switchover and
allows a dynamic CR-LSP to be restored.
Perform the following configurations on a GR node.
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Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls rsvp-te hello full-gr
The RSVP GR function and the RSVP GR helper function are enabled.
By default, the RSVP GR function and the RSVP GR helper function are disabled.
----End
6.22.3 (Optional) Enabling the RSVP GR Helper Function
Context
By being enabled with RSVP GR Helper, a device supports the GR capability of its
neighbor.
RSVP GR takes effect on the RSVP GR-enabled neighbor automatically after the
neighbor is enabled with RSVP GR. If the GR node's neighbor is a GR node, do not
perform the following configurations. If the GR node's neighbor is not a GR node,
perform the following configurations.
Perform the following configurations on GR Helper nodes.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls rsvp-te hello support-peer-gr
The function of RSVP GR Helper on the neighbor is enabled.
----End
6.22.4 (Optional) Configuring Hello Sessions Between RSVP
GR Nodes
Context
If TE FRR is deployed, a Hello session is required between a PLR and an MP.
Perform the following configurations on the PLR and MP of the bypass CR-LSP.
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Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls rsvp-te hello nodeid-session ip-address
A Hello session is set up between a restarting node and a neighbor node.
ip-address is the LSR ID of the RSVP neighbor.
----End
6.22.5 (Optional) Modifying Basic Time
Context
After an active/standby switchover starts, an RSVP GR node has an RSVP
smoothing period, during which the data plane continues forwarding data if the
control plane is not restored. After RSVP smoothing is completed, a restart timer is
started.
Restart timer value = Basic time + Number of ingress LSPs x 60 ms + Number of
none-ingress LSPs x 15 ms
In this formula, the default basic time is 90 seconds and is configurable by using a
command line, and the number of LSPs is the number of LSPs with the local node
being the ingress.
After the restart timer expires, the recovery timer is started.
Recovery timer = Restart time + Total number of LSPs x 40 ms
Perform the following configurations on a GR node.
Procedure
Step 1 Run system-view
The system view is displayed.
Step 2 Run mpls
The MPLS view is displayed.
Step 3 Run mpls rsvp-te hello basic-restart-time basic-restart-time
The RSVP GR basic time is modified.
By default, the RSVP GR basic time is 90 seconds.
----End
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6.22.6 Verifying the RSVP GR Configuration
Prerequisites
The configurations of RSVP GR are complete.
Procedure
●
Run the display mpls rsvp-te graceful-restart command to check the status
of the local RSVP GR.
●
Run the display mpls rsvp-te graceful-restart peer [ { interface interfacetype interface-number | node-id } [ ip-address ] ] command to check the
status of RSVP GR on a neighbor.
----End
6.23 Maintaining MPLS TE
6.23.1 Verifying the Connectivity of the TE Tunnel
Procedure
●
Run the ping lsp [ -a source-ip | -c count | -exp exp-value | -h ttl-value | -m
interval | -r reply-mode | -s packet-size | -t time-out | -v ] * te tunnel
interface-number [ hot-standby | primary ] [ draft6 ] command to check the
connectivity of the TE tunnel between the ingress and egress.
If draft6 is specified, the ping lsp command is implemented according to
draft-ietf-mpls-lsp-ping-06. By default, the command is implemented
according to RFC 4379. If the hot-standby parameter is specified, the hotstandby CR-LSP can be tested.
●
Run the tracert lsp [ -a source-ip | -exp exp-value | -h ttl-value | -r replymode | -t time-out ] * te tunnel interface-number [ hot-standby | primary ]
[ draft6 ] command to trace the hops of a TE tunnel.
If draft6 is specified, the tracert lsp command is implemented according to
draft-ietf-mpls-lsp-ping-06. By default, the command is implemented
according to RFC 4379. If the hot-standby parameter is specified, the hotstandby CR-LSP can be tested.
----End
6.23.2 Verifying a TE Tunnel By Using NQA
Procedure
After configuring MPLS TE, you can use NQA to check the connectivity and jitter
of the TE tunnel. For detailed configurations, see NQA Configuration in the S1720,
S2700, S5700, and S6720 V200R011C10 Configuration Guide - Network
Management and Monitoring.
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6.23.3 Enabling the MPLS TE Trap Function
Context
To facilitate operation and maintenance and learn about the running status of the
MPLS network, configure the MPLS TE trap function so that the device can notify
the NMS of the RSVP and MPLS TE status change and usage of dynamic labels.
If the proportion of used MPLS resources, such as LSPs, dynamic labels, and
dynamic BFD sessions to all supported ones reaches a specified upper limit, new
MPLS services may fail to be established because of insufficient resources. To
facilitate operation and maintenance, an upper alarm threshold of MPLS resource
usage can be set. If MPLS resource usage reaches the specified upper alarm
threshold, an alarm is generated.
Procedure
●
Configure the RSVP trap function.
a.
Run the system-view command to enter the system view.
b.
Run the snmp-agent trap enable feature-name mpls_rsvp [ trap-name
trap-name ] command to enable the trap function for the RSVP module.
By default, the trap function is disabled for the RSVP module.
●
Configure the alarm function for LSPM.
a.
Run the system-view command to enter the system view.
b.
Run the snmp-agent trap enable feature-name mpls_lspm trap-name
trapname command to enable the trap function for the LSPM module.
By default, the trap function is disabled for the LSPM module.
c.
Run the snmp-agent trap suppress feature-name lsp trap-name
{ mplsxcup | mplsxcdown } trap-interval trap-interval [ max-trapnumber max-trap-number ] command to set the interval for suppressing
excess LSP traps.
By default, the interval for suppressing the display of excessive LSP traps
is 300 seconds, and a maximum of three LSP traps can be sent in the
suppression interval.
d.
Run the mpls command to enter the MPLS view.
e.
Run the mpls dynamic-label-number threshold-alarm upper-limit
upper-limit-value lower-limit lower-limit-value command to set alarm
thresholds for dynamic label usage.
You can set the following parameters:
n
n
n
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upper-limit-value: a percent indicating the upper limit of dynamic
labels. If dynamic label usage reaches the upper limit, an alarm is
generated. An upper limit less than or equal to 95% is
recommended.
lower-limit-value: a percent indicating the lower limit of dynamic
labels. If dynamic label usage falls below the lower limit, an alarm is
generated.
The value of upper-limit-value must be greater than that of lowerlimit-value.
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By default, the upper limit is 80%, and the lower limit is 70%, which are
recommended.
● Each command only configures the trigger conditions for an alarm and its
clear alarm. Although trigger conditions are met, the alarm and its clear
alarm can be generated only after the snmp-agent trap enable featurename mpls_lspm trap-name { hwMplsDynamicLabelThresholdExceed |
hwMplsDynamicLabelThresholdExceedClear } command is run to enable
the device to generate a dynamic label insufficiency alarm and its clear alarm.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwMplsDynamicLabelTotalCountExceed |
hwMplsDynamicLabelTotalCountExceedClear } command is run to enable
the device to generate limit-reaching alarms and their clear alarms, the
following situations occur:
f.
●
If the number of dynamic labels reaches the maximum number of
dynamic labels supported by a device, a limit-reaching alarm is
generated.
●
If the number of dynamic labels falls below 95% of the maximum
number of dynamic labels supported by the device, a clear alarm is
generated.
Run the mpls rsvp-lsp-number [ ingress | transit | egress ] thresholdalarm upper-limit upper-limit-value lower-limit lower-limit-value
command to configure the upper and lower thresholds of alarms for
RSVP LSP usage.
The parameters in this command are described as follows:
n
upper-limit-value specifies the upper threshold of alarms for RSVP
LSP usage. An alarm is generated when the proportion of established
RSVP LSPs to total supported RSVP LSPs reaches the upper limit.
n
lower-limit-value specifies the lower threshold of clear alarms for
RSVP LSP usage. A clear alarm is generated when the proportion of
established RSVP LSPs to total supported RSVP LSPs falls below the
lower limit.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
The default upper limit of an alarm for RSVP LSP usage is 80%. The
default lower limit of a clear alarm for RSVP LSP usage is 75%. Using the
default upper limit and lower limit is recommended.
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● This command configures the alarm threshold for RSVP LSP usage. The alarm
that the number of RSVP LSPs reached the upper threshold is generated only
when the command snmp-agent trap enable feature-name mpls_lspm
trap-name hwmplslspthresholdexceed is configured, and the actual RSVP
LSP usage reaches the upper limit of the alarm threshold. The alarm that the
number of RSVP LSPs fell below the lower threshold is generated only when
the command snmp-agent trap enable feature-name mpls_lspm trapname hwmplslspthresholdexceedclear is configured, and the actual RSVP
LSP usage falls below the lower limit of the clear alarm threshold.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwmplslsptotalcountexceed | hwmplslsptotalcountexceedclear }
command is run to enable LSP limit-crossing alarm and LSP limit-crossing
clear alarm, an alarm is generated in the following situations:
g.
●
If the total number of RSVP LSPs reaches the upper limit, a limit-crossing
alarm is generated.
●
If the total number of RSVP LSPs falls below 95% of the upper limit, a
limit-crossing clear alarm is generated.
Run the mpls total-crlsp-number [ ingress | transit | egress ]
threshold-alarm upper-limit upper-limit-value lower-limit lower-limitvalue command to configure the upper and lower thresholds of alarms
for total CR-LSP usage.
The parameters in this command are described as follows:
n
upper-limit-value specifies the upper threshold of alarms for total
CR-LSP usage. An alarm is generated when the proportion of
established CR-LSPs to total supported CR-LSPs reaches the upper
limit.
n
lower-limit-value specifies the lower threshold of clear alarms for
total CR-LSP usage. A clear alarm is generated when the proportion
of established CR-LSPs to total supported CR-LSPs falls below the
lower limit.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
The default upper limit of an alarm for total CR-LSP usage is 80%. The
default lower limit of a clear alarm for total CR-LSP usage is 75%. Using
the default upper limit and lower limit is recommended.
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● This command configures the alarm threshold for total CR-LSP usage. The
alarm that the number of total CR-LSPs reached the upper threshold is
generated only when the command snmp-agent trap enable feature-name
mpls_lspm trap-name hwmplslspthresholdexceed is configured, and the
actual total CR-LSP usage reaches the upper limit of the alarm threshold. The
alarm that the number of total CR-LSPs fell below the lower threshold is
generated only when the command snmp-agent trap enable feature-name
mpls_lspm trap-name hwmplslspthresholdexceedclear is configured, and
the actual total CR-LSP usage falls below the lower limit of the clear alarm
threshold.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwmplslsptotalcountexceed | hwmplslsptotalcountexceedclear }
command is run to enable LSP limit-crossing alarm and LSP limit-crossing
clear alarm, an alarm is generated in the following situations:
●
●
If the total number of CR-LSPs reaches the upper limit, a limit-crossing
alarm is generated.
●
If the total number of CR-LSPs falls below 95% of the upper limit, a
limit-crossing clear alarm is generated.
Configure MPLS resource threshold-related alarms.
a.
Run the system-view command to enter the system view.
b.
Run the mpls command to enter the MPLS view.
c.
Run the mpls rsvp-peer-number threshold-alarm upper-limit upperlimit-value lower-limit lower-limit-value command to configure the
conditions that trigger the threshold-reaching alarm and its clear alarm
for RSVP neighbors.
Note the following issues when configuring trigger conditions:
n
upper-limit-value: upper alarm threshold for the proportion of
configured RSVP neighbors to all RSVP neighbors supported by a
device.
n
lower-limit-value: lower alarm threshold for the proportion of
configured RSVP neighbors to all RSVP neighbors supported by a
device.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
By default, the upper alarm threshold is 80%, and the lower alarm
threshold is 75%, which are recommended.
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● The mpls rsvp-peer-number threshold-alarm command only configures the
trigger conditions for an alarm and its clear alarm. Although trigger
conditions are met, the alarm and its clear alarm can be generated only after
the snmp-agent trap enable feature-name mpls_rsvp trap-name
{ hwrsvpteifnbrthresholdexceed | hwrsvpteifnbrthresholdexceedclear }
command is run to enable the device to generate the RSVP neighbor
threshold-reaching alarm and its clear alarm.
● After the snmp-agent trap enable feature-name mpls_rsvp trap-name
{ hwrsvpteifnbrtotalcountexceed | hwrsvpteifnbrtotalcountexceedclear }
command is run to enable the device to generate limit-reaching alarms and
their clear alarms, the following situations occur:
d.
●
If the number of configured RSVP neighbors reaches the maximum
number of RSVP neighbors supported by a device, a limit-reaching alarm
is generated.
●
If the number of configured RSVP neighbors falls below 95% of the
maximum number of RSVP neighbors supported by the device, a clear
alarm is generated.
Run the mpls bfd-te-number threshold-alarm upper-limit upper-limitvalue lower-limit lower-limit-value command to configure the conditions
that trigger the threshold-reaching alarm and its clear alarm for dynamic
BFD sessions for TE.
Note the following issues when configuring trigger conditions:
n
upper-limit-value: upper alarm threshold for the proportion of used
TE resources to all TE resources supported by a device.
n
lower-limit-value: lower alarm threshold for the proportion of used
TE resources to all TE resources supported by a device.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
By default, the upper alarm threshold is 80%, and the lower alarm
threshold is 75%, which are recommended.
● Each command only configures the trigger conditions for an alarm and its
clear alarm. Although trigger conditions are met, the alarm and its clear
alarm can be generated only after the snmp-agent trap enable featurename mpls_lspm trap-name { hwmplsresourcethresholdexceed |
hwmplsresourcethresholdexceedclear } command is run to enable the
device to generate an MPLS resource insufficiency alarm and its clear alarm.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwmplsresourcetotalcountexceed |
hwmplsresourcetotalcountexceedclear } command is run to enable the
device to generate limit-reaching alarms and their clear alarms, the following
situations occur:
e.
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●
If the number of used TE resources reaches the maximum number of TE
resources supported by a device, a limit-reaching alarm is generated.
●
If the number of used TE resources falls below 95% of the maximum
number of TE resources supported by a device, a clear alarm is
generated.
Run the mpls autobypass-tunnel-number threshold-alarm upper-limit
upper-limit-value lower-limit lower-limit-value command to configure
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the conditions that trigger the threshold-reaching alarm and its clear
alarm for Auto bypass tunnel interfaces.
Note the following issues when configuring trigger conditions:
n
upper-limit-value: upper alarm threshold for the proportion of used
TE resources to all TE resources supported by a device.
n
lower-limit-value: lower alarm threshold for the proportion of used
TE resources to all TE resources supported by a device.
n
The value of upper-limit-value must be greater than that of lowerlimit-value.
By default, the upper alarm threshold is 80%, and the lower alarm
threshold is 75%, which are recommended.
● Each command only configures the trigger conditions for an alarm and its
clear alarm. Although trigger conditions are met, the alarm and its clear
alarm can be generated only after the snmp-agent trap enable featurename mpls_lspm trap-name { hwmplsresourcethresholdexceed |
hwmplsresourcethresholdexceedclear } command is run to enable the
device to generate an MPLS resource insufficiency alarm and its clear alarm.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwmplsresourcetotalcountexceed |
hwmplsresourcetotalcountexceedclear } command is run to enable the
device to generate limit-reaching alarms and their clear alarms, the following
situations occur:
●
If the number of used TE resources reaches the maximum number of TE
resources supported by a device, a limit-reaching alarm is generated.
●
If the number of used TE resources falls below 95% of the maximum
number of TE resources supported by a device, a clear alarm is
generated.
----End
Verifying the Configuration
●
Run the display snmp-agent trap feature-name mpls_rsvp all command to
view status of all traps on the RSVP module.
●
Run the display snmp-agent trap feature-name mpls_lspm all command to
view status of all traps on the LSPM module.
6.23.4 Configuring Conditions That Trigger CSPF Resource
Threshold-Reaching Alarms
Procedure
Step 1 Run the system-view command to enter the system view.
Step 2 Run the mpls command to enter the MPLS view.
Step 3 Run the mpls { cspf-link-number | cspf-node-number | cspf-nlsa-number | cspfsrlg-number } threshold-alarm upper-limit upper-limit-value lower-limit lowerlimit-value command to set the upper and lower alarm thresholds for proportion
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of used CSPF resources to the maximum number of CSPF resources that device
supports.
Configure the following parameters in the preceding command:
●
upper-limit-value specifies the upper alarm threshold (percent) for the
proportion of used CSPF resources to the maximum number of CSPF resources
that a device supports.
●
lower-limit-value specifies the lower alarm threshold (percent) for the
proportion of used CSPF resources to the maximum number of CSPF resources
that a device supports.
●
upper-limit-value must be greater than lower-limit-value.
By default, the upper threshold for alarms is 80%, and the lower threshold for
clear alarms is 75%, which are recommended.
● The mpls cspf threshold-alarm command only configures the trigger conditions for
alarms and clear alarms. Although trigger conditions are met, an alarm and its clear
alarm can be generated only after the snmp-agent trap enable feature-name
mpls_lspm trap-name { hwmplsresourcethresholdexceed |
hwmplsresourcethresholdexceedclear } command is run to enable the device to
generate an MPLS resource insufficiency alarm and its clear alarm.
● After the snmp-agent trap enable feature-name mpls_lspm trap-name
{ hwmplsresourcetotalcountexceed | hwmplsresourcetotalcountexceedclear }
command is run to enable the device to generate maximum number-reaching alarms
and their clear alarms, the following situations occur:
–
If the number of used CSPF resources reaches the maximum number of CSPF
resources supported by a device, a maximum number-reaching alarm is generated.
–
If the number of used CSPF resources falls to 95% or below of the maximum
number of CSPF resources supported by a device, a clear alarm is generated.
----End
6.23.5 Clearing the Operation Information
Context
NOTICE
Cleared statistics cannot be restored. Exercise caution when you use the command.
Procedure
●
Run the reset mpls rsvp-te statistics { global | interface [ interface-type
interface-number ] } command in the user view to clear statistics about RSVPTE.
●
Run the reset mpls stale-interface [ interface-index ] command in the user
view to delete the information about MPLS interfaces in the Stale state.
----End
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6.23.6 Verifying Information About TE
Context
To check TE information during routine maintenance, run the following display
commands in any view.
Procedure
●
Run the display default-parameter mpls te management command to
check default parameters of MPLS TE management.
●
Run the display mpls te tunnel statistics or display mpls lsp statistics
command to check tunnel statistics.
●
Run the display mpls te tunnel-interface last-error [ tunnel-name ]
command to check information about tunnel faults.
●
Run the display mpls te tunnel-interface failed command to check MPLS TE
tunnels that fail to be established or are being established.
●
Run the display mpls te tunnel-interface traffic-state [ tunnel-name ]
command to check traffic on the tunnel interface of the local node.
●
Run the display mpls rsvp-te statistics { global | interface [ interface-type
interface-number ] } command to check RSVP-TE statistics.
●
Run the display mpls rsvp-te statistics fast-reroute command to check TE
FRR statistics.
----End
6.23.7 Resetting the Tunnel Interface
Context
To make the tunnel-related configuration take effect, you can run the mpls te
commit command in the tunnel interface view and run the reset command in the
user view.
If the configuration is modified in the interface view of the TE tunnel but the mpls te
commit command is not configured, the system cannot execute the reset mpls te tunnelinterface tunnel command to re-establish the tunnel.
Procedure
●
Run the reset mpls te tunnel-interface tunnel interface-number command
to reset the tunnel interface.
----End
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6.23.8 Resetting the RSVP Process
Context
NOTICE
Resetting the RSVP process results in the release and reestablishment of all RSVP
CR-LSPs.
To reestablish all RSVP CR-LSPs or verify the operation process of RSVP, run the
following reset command in the user view.
Procedure
●
Run the reset mpls rsvp-te command to reset the RSVP process.
----End
6.23.9 Deleting or Resetting the Bypass Tunnel
Context
In a scenario where auto TE FRR is used, you can run the following reset
command to release or re-establish bypass tunnels.
Procedure
Run the reset mpls te auto-frr { lsp-id ingress-lsr-id tunnel-id | name
bypass-tunnel-name } command to delete or reset the auto FRR bypass
tunnel.
●
----End
6.24 Configuration Examples for MPLS TE
6.24.1 Example for Configuring a Static MPLS TE Tunnel
Networking Requirements
As shown in Figure 6-35, static TE tunnels from LSRA to LSRC and from LSRC to
LSRA need to be set up.
Figure 6-35 Networking of static MPLS TE tunnels
Loopback1
1.1.1.9/32
GE0/0/1
VLANIF100
172.1.1.1/24
LSRA
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Loopback1
2.2.2.9/32
GE0/0/1
GE0/0/2
VLANIF100
VLANIF200
172.1.1.2/24
172.2.1.1/24
LSRB
Copyright © Huawei Technologies Co., Ltd.
Loopback1
3.3.3.9/32
GE0/0/1
VLANIF200
172.2.1.2/24
LSRC
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Configuration Roadmap
The configuration roadmap is as follows:
1.
Assign an IP address to each interface on each LSR and configure OSPF to
ensure that there are reachable routes between LSRs.
2.
Configure an ID for each LSR and globally enable MPLS and MPLS TE on each
LSR and interface.
3.
Create a tunnel interface on the ingress node and set the tunnel type to static
CR-LSP.
4.
Configure the static LSP bound to the tunnel; specify the next hop address
and outgoing label on the ingress node; specify the inbound interface,
incoming label, next hop address, and outgoing label on the transit node;
specify the incoming label and inbound interface on the egress node.
● The value of the outgoing label of each node is the value of the incoming label of its
next node.
● When running the static-cr-lsp ingress { tunnel-interface tunnel interface-number |
tunnel-name } destination destination-address { nexthop next-hop-address | outgoinginterface interface-type interface-number } * out-label out-label command to configure
the ingress node of a CR-LSP, ensure that tunnel-name must be the same as the tunnel
name created by using the interface tunnel interface-number command. tunnel-name
is a case-sensitive character string without spaces. For example, the name of the tunnel
created by using the interface tunnel 1 command is Tunnel1. In this case, the
parameter of the ingress node of the static CR-LSP is Tunnel1; otherwise, the tunnel
cannot be created. There is no such limitation on the transit node and egress node.
Procedure
Step 1 Configure an IP address and routing protocol for each interface.
# Configure LSRA. Configure IP addresses for interfaces of LSRB and LSRC and
OSPF according to Figure 6-35. The configurations of LSRB and LSRC are similar
to the configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] vlan batch 100
[LSRA] interface vlanif 100
[LSRA-Vlanif100] ip address 172.1.1.1 255.255.255.0
[LSRA-Vlanif100] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 100
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface loopback 1
[LSRA-LoopBack1] ip address 1.1.1.9 255.255.255.255
[LSRA-LoopBack1] quit
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
After the configurations are complete, OSPF neighbor relationships can be set up
between LSRA, LSRB, and LSRC. Run the display ospf peer command. You can see
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that the neighbor status is Full. Run the display ip routing-table command. You
can see that LSRs have learnt the routes to Loopback1 of each other.
Step 2 Configure basic MPLS functions and enable MPLS TE.
# Configure LSRA. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] mpls te
[LSRA-mpls] quit
[LSRA] interface vlanif 100
[LSRA-Vlanif100] mpls
[LSRA-Vlanif100] mpls te
[LSRA-Vlanif100] quit
Step 3 Configure MPLS TE tunnels.
# On LSRA, create an MPLS TE tunnel from LSRA to LSRC.
[LSRA] interface tunnel 1
[LSRA-Tunnel1] ip address unnumbered interface loopback 1
[LSRA-Tunnel1] tunnel-protocol mpls te
[LSRA-Tunnel1] destination 3.3.3.9
[LSRA-Tunnel1] mpls te tunnel-id 100
[LSRA-Tunnel1] mpls te signal-protocol cr-static
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit
# On LSRC, create an MPLS TE tunnel from LSRC to LSRA.
[LSRC] interface tunnel 1
[LSRC-Tunnel1] ip address unnumbered interface loopback 1
[LSRC-Tunnel1] tunnel-protocol mpls te
[LSRC-Tunnel1] destination 1.1.1.9
[LSRC-Tunnel1] mpls te tunnel-id 200
[LSRC-Tunnel1] mpls te signal-protocol cr-static
[LSRC-Tunnel1] mpls te commit
[LSRC-Tunnel1] quit
Step 4 Create a static CR-LSP from LSRA to LSRC.
# Configure LSRA as the ingress node of the static CR-LSP.
[LSRA] static-cr-lsp ingress tunnel-interface Tunnel1 destination 3.3.3.9 nexthop 172.1.1.2 out-label 20
# Configure LSRB as the transit node of the static CR-LSP.
[LSRB] static-cr-lsp transit LSRA2LSRC incoming-interface vlanif 100 in-label 20 nexthop 172.2.1.2 outlabel 30
# Configure LSRC as the egress node of the static CR-LSP.
[LSRC] static-cr-lsp egress LSRA2LSRC incoming-interface vlanif 200 in-label 30
Step 5 Create a static CR-LSP from LSRC to LSRA.
# Configure LSRC as the ingress node of the static CR-LSP.
[LSRC] static-cr-lsp ingress tunnel-interface Tunnel1 destination 1.1.1.9 nexthop 172.2.1.1 out-label
120
# Configure LSRB as the transit node of the static CR-LSP.
[LSRB] static-cr-lsp transit LSRC2LSRA incoming-interface vlanif 200 in-label 120 nexthop 172.1.1.1
out-label 130
# Configure LSRA as the egress node of the static CR-LSP.
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[LSRA] static-cr-lsp egress LSRC2LSRA incoming-interface vlanif 100 in-label 130
Step 6 Verify the configuration.
After the configurations are complete, run the display interface tunnel command
on LSRA. You can see that the tunnel interface status is Up.
The display on LSRA is used as an example.
[LSRA] display interface tunnel 1
Tunnel1 current state : UP
Line protocol current state : UP
...
Run the display mpls te tunnel command on each LSR to view the MPLS TE
tunnel status.
The display on LSRA is used as an example.
[LSRA] display mpls te tunnel
-----------------------------------------------------------------------------Ingress LsrId Destination
LSPID In/Out Label
R Tunnel-name
-----------------------------------------------------------------------------1.1.1.9
3.3.3.9
1
--/20
I Tunnel1
130/-E LSRC2LSRA
Run the display mpls lsp or display mpls static-cr-lsp command on each LSR to
view the static CR-LSP status.
The display on LSRA is used as an example.
[LSRA] display mpls static-cr-lsp
TOTAL
:2
STATIC CRLSP(S)
UP
:2
STATIC CRLSP(S)
DOWN
:0
STATIC CRLSP(S)
Name
FEC
I/O Label I/O If
Tunnel1
3.3.3.9/32
NULL/20
-/Vlanif100
LSRC2LSRA
-/130/NULL
Vlanif100/-
Status
Up
Up
When a static CR-LSP is used to establish an MPLS TE tunnel, the transit node and
the egress node do not forward packets according to the specified incoming label
and outgoing label. Therefore, no EFC information is displayed on LSRB or LSRC.
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 100
#
mpls lsr-id 1.1.1.9
mpls
mpls te
#
interface Vlanif100
ip address 172.1.1.1 255.255.255.0
mpls
mpls te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
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interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
interface Tunnel1
ip address unnumbered interface LoopBack1
tunnel-protocol mpls te
destination 3.3.3.9
mpls te signal-protocol cr-static
mpls te tunnel-id 100
mpls te commit
#
ospf 1
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 172.1.1.0 0.0.0.255
#
static-cr-lsp ingress tunnel-interface Tunnel1 destination 3.3.3.9 nexthop 172.1.1.2 out-label 20
bandwidth ct0 0
static-cr-lsp egress LSRC2LSRA incoming-interface Vlanif100 in-label 130
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 100 200
#
mpls lsr-id 2.2.2.9
mpls
mpls te
#
interface Vlanif100
ip address 172.1.1.2 255.255.255.0
mpls
mpls te
#
interface Vlanif200
ip address 172.2.1.1 255.255.255.0
mpls
mpls te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 200
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
ospf 1
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.2.1.0 0.0.0.255
#
static-cr-lsp transit LSRA2LSRC incoming-interface Vlanif100 in-label 20 nexthop 172.2.1.2 out-label
30 bandwidth ct0 0
static-cr-lsp transit LSRC2LSRA incoming-interface Vlanif200 in-label 120 nexthop 172.1.1.1 out-label
130 bandwidth ct0 0
#
return
●
LSRC configuration file
#
sysname LSRC
#
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vlan batch 200
#
mpls lsr-id 3.3.3.9
mpls
mpls te
#
interface Vlanif200
ip address 172.2.1.2 255.255.255.0
mpls
mpls te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 200
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
interface Tunnel1
ip address unnumbered interface LoopBack1
tunnel-protocol mpls te
destination 1.1.1.9
mpls te signal-protocol cr-static
mpls te tunnel-id 200
mpls te commit
#
ospf 1
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 172.2.1.0 0.0.0.255
#
static-cr-lsp egress LSRA2LSRC incoming-interface Vlanif200 in-label 30
static-cr-lsp ingress tunnel-interface Tunnel1 destination 1.1.1.9 nexthop 172.2.1.1 out-label 120
bandwidth ct0 0
#
return
6.24.2 Example for Configuring a Dynamic MPLS TE Tunnel
Networking Requirements
As shown in Figure 6-36, an enterprise establishes its own MPLS backbone
network with LSRA, LSRB, and LSRC deployed. The MPLS backbone network uses
IS-IS, and LSRA, LSRB, and LSRC are level-2 devices. A tunnel needs to be set up
over the public network on the MPLS backbone network to transmit L2VPN or
L3VPN services, and the tunnel must be able to adapt to network topology
changes to ensure stable data transmission.
RSVP-TE is used to establish a dynamic MPLS TE tunnel.
Figure 6-36 Networking of a dynamic MPLS TE tunnel
Loopback1
1.1.1.9/32
GE0/0/1
VLANIF100
172.1.1.1/24
LSRA
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2.2.2.9/32
GE0/0/1
GE0/0/2
VLANIF100
VLANIF200
172.1.1.2/24
172.2.1.1/24
LSRB
Copyright © Huawei Technologies Co., Ltd.
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3.3.3.9/32
GE0/0/1
VLANIF200
172.2.1.2/24
LSRC
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6 MPLS TE Configuration
Configuration Roadmap
The configuration roadmap is as follows:
1.
On the MPLS backbone network, MPLS LDP and MPLS TE tunnels can carry
L2VPN or L3VPN services. Configure an MPLS TE tunnel to ensure stable data
transmission upon frequent topology changes on the enterprise network.
2.
Configure IS-IS to ensure that there are reachable routes between devices on
the MPLS backbone network.
3.
Enable MPLS TE and RSVP-TE on each node so that an MPLS TE tunnel can be
set up.
4.
Enable IS-IS TE and change the cost type so that TE information can be
advertised to other nodes through IS-IS.
5.
Create a tunnel interface on the ingress node, configure tunnel attributes, and
enable MPLS TE CSPF to create a dynamic MPLS TE tunnel.
Procedure
Step 1 Assign IP addresses to interfaces.
# Configure LSRA. Configure IP addresses for interfaces of LSRB and LSRC
according to Figure 6-36. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] vlan batch 100
[LSRA] interface vlanif 100
[LSRA-Vlanif100] ip address 172.1.1.1 255.255.255.0
[LSRA-Vlanif100] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 100
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface loopback 1
[LSRA-LoopBack1] ip address 1.1.1.9 255.255.255.255
[LSRA-LoopBack1] quit
Step 2 Configure IS-IS to advertise routes.
# Configure LSRA.
[LSRA] isis 1
[LSRA-isis-1] network-entity 00.0005.0000.0000.0001.00
[LSRA-isis-1] is-level level-2
[LSRA-isis-1] quit
[LSRA] interface vlanif 100
[LSRA-Vlanif100] isis enable 1
[LSRA-Vlanif100] quit
[LSRA] interface loopback 1
[LSRA-LoopBack1] isis enable 1
[LSRA-LoopBack1] quit
# Configure LSRB.
[LSRB] isis 1
[LSRB-isis-1] network-entity 00.0005.0000.0000.0002.00
[LSRB-isis-1] is-level level-2
[LSRB-isis-1] quit
[LSRB] interface vlanif 100
[LSRB-Vlanif100] isis enable 1
[LSRB-Vlanif100] quit
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[LSRB] interface vlanif 200
[LSRB-Vlanif200] isis enable 1
[LSRB-Vlanif200] quit
[LSRB] interface loopback 1
[LSRB-LoopBack1] isis enable 1
[LSRB-LoopBack1] quit
# Configure LSRC.
[LSRC] isis 1
[LSRC-isis-1] network-entity 00.0005.0000.0000.0003.00
[LSRC-isis-1] is-level level-2
[LSRC-isis-1] quit
[LSRC] interface vlanif 200
[LSRC-Vlanif200] isis enable 1
[LSRC-Vlanif200] quit
[LSRC] interface loopback 1
[LSRC-LoopBack1] isis enable 1
[LSRC-LoopBack1] quit
After the configurations are complete, run the display ip routing-table command
on each LSR. You can see that the LSRs have learned the routes from each other.
The display on LSRA is used as an example.
[LSRA] display ip routing-table
Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------Routing Tables: Public
Destinations : 8
Routes : 8
Destination/Mask
Proto Pre Cost
1.1.1.9/32 Direct 0 0
2.2.2.9/32 ISIS-L2 15 10
3.3.3.9/32 ISIS-L2 15 20
127.0.0.0/8 Direct 0 0
127.0.0.1/32 Direct 0 0
172.1.1.0/24 Direct 0 0
172.1.1.1/32 Direct 0 0
172.2.1.0/24 ISIS-L2 15 20
Flags NextHop
D 127.0.0.1
D 172.1.1.2
D 172.1.1.2
D 127.0.0.1
D 127.0.0.1
D 172.1.1.1
D 127.0.0.1
D 172.1.1.2
Interface
LoopBack1
Vlanif100
Vlanif100
InLoopBack0
InLoopBack0
Vlanif100
Vlanif100
Vlanif100
Step 3 Configure basic MPLS functions and enable MPLS TE and RSVP-TE.
Enable MPLS, MPLS TE, and RSVP-TE globally on each node and interfaces along
the tunnel.
# Configure LSRA. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] mpls te
[LSRA-mpls] mpls rsvp-te
[LSRA-mpls] quit
[LSRA] interface vlanif 100
[LSRA-Vlanif100] mpls
[LSRA-Vlanif100] mpls te
[LSRA-Vlanif100] mpls rsvp-te
[LSRA-Vlanif100] quit
Step 4 Configure IS-IS TE.
# Configure LSRA. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] isis 1
[LSRA-isis-1] cost-style wide
[LSRA-isis-1] traffic-eng level-2
[LSRA-isis-1] quit
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Step 5 Configure an MPLS TE tunnel interface and enable MPLS TE CSPF.
# On the ingress node of the tunnel, create a tunnel interface, and set the IP
address, tunnel protocol, destination IP address, tunnel ID, and dynamic signaling
protocol for the tunnel interface. Then, run the mpls te commit command to
commit the configuration.
# Configure LSRA.
[LSRA] interface tunnel 1
[LSRA-Tunnel1] ip address unnumbered interface loopback 1
[LSRA-Tunnel1] tunnel-protocol mpls te
[LSRA-Tunnel1] destination 3.3.3.9
[LSRA-Tunnel1] mpls te tunnel-id 100
[LSRA-Tunnel1] mpls te signal-protocol rsvp-te
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit
[LSRA] mpls
[LSRA-mpls] mpls te cspf
[LSRA-mpls] quit
Step 6 Verify the configuration.
After the configurations are complete, run the display interface tunnel command
on LSRA. You can see that the tunnel interface status is Up.
[LSRA] display interface tunnel
Tunnel1 current state : UP
Line protocol current state : UP
Last line protocol up time : 2013-01-14 09:18:46
Description:
...
Run the display mpls te tunnel-interface command on LSRA. You can view
tunnel interface information.
[LSRA] display mpls te tunnel-interface
---------------------------------------------------------------Tunnel1
---------------------------------------------------------------Tunnel State Desc : UP
Active LSP
: Primary LSP
Session ID
: 100
Ingress LSR ID
: 1.1.1.9
Egress LSR ID: 3.3.3.9
Admin State
: UP
Oper State : UP
Primary LSP State
: UP
Main LSP State
: READY
LSP ID : 3
Run the display mpls te tunnel verbose command on LSRA. You can view
detailed information about the tunnel.
[LSRA] display mpls te tunnel verbose
No
: 1
Tunnel-Name
: Tunnel1
Tunnel Interface Name : Tunnel1
TunnelIndex
: 1
LSP Index
: 2048
Session ID
: 100
LSP ID
: 3
LSR Role
: Ingress
LSP Type
: Primary
Ingress LSR ID
: 1.1.1.9
Egress LSR ID
: 3.3.3.9
In-Interface
: Out-Interface
: Vlanif100
Sign-Protocol
: RSVP TE
Resv Style
: SE
IncludeAnyAff
: 0x0
ExcludeAnyAff
: 0x0
IncludeAllAff
: 0x0
LspConstraint
: ER-Hop Table Index
: AR-Hop Table Index: C-Hop Table Index
: -
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PrevTunnelIndexInSession: NextTunnelIndexInSession: PSB Handle
: 16388
Created Time
: 2013-09-16 11:51:21+00:00
RSVP LSP Type
: -------------------------------DS-TE Information
-------------------------------Bandwidth Reserved Flag : Unreserved
CT0 Bandwidth(Kbit/sec) : 0
CT1 Bandwidth(Kbit/sec): 0
CT2 Bandwidth(Kbit/sec) : 0
CT3 Bandwidth(Kbit/sec): 0
CT4 Bandwidth(Kbit/sec) : 0
CT5 Bandwidth(Kbit/sec): 0
CT6 Bandwidth(Kbit/sec) : 0
CT7 Bandwidth(Kbit/sec): 0
Setup-Priority
: 7
Hold-Priority
: 7
-------------------------------FRR Information
-------------------------------Primary LSP Info
TE Attribute Flag
: 0x3
Protected Flag : 0x0
Bypass In Use
: Not Exists
Bypass Tunnel Id
: BypassTunnel
: Bypass LSP ID
: FrrNextHop
: ReferAutoBypassHandle : FrrPrevTunnelTableIndex : FrrNextTunnelTableIndex: Bypass Attribute(Not configured)
Setup Priority
: Hold Priority
: HopLimit
: Bandwidth
: IncludeAnyGroup
: ExcludeAnyGroup : IncludeAllGroup
: Bypass Unbound Bandwidth Info(Kbit/sec)
CT0 Unbound Bandwidth : CT1 Unbound Bandwidth: CT2 Unbound Bandwidth : CT3 Unbound Bandwidth: CT4 Unbound Bandwidth : CT5 Unbound Bandwidth: CT6 Unbound Bandwidth : CT7 Unbound Bandwidth: -------------------------------BFD Information
-------------------------------NextSessionTunnelIndex : PrevSessionTunnelIndex: NextLspId
: PrevLspId
: -
Run the display mpls te cspf tedb all command on LSRA. You can view link
information in the TEDB.
[LSRA] display mpls te cspf tedb all
Maximum Nodes Supported: 512 Current Total Node Number: 3
Maximum Links Supported: 2048 Current Total Link Number: 4
Maximum SRLGs supported: 5120 Current Total SRLG Number: 0
ID
Router-ID
IGP
Process-ID
Area
Link-Count
1
1.1.1.9
ISIS
1
Level-2
1
2
2.2.2.9
ISIS
1
Level-2
2
3
3.3.3.9
ISIS
1
Level-2
1
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 100
#
mpls lsr-id 1.1.1.9
mpls
mpls te
mpls rsvp-te
mpls te cspf
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#
isis 1
is-level level-2
cost-style wide
network-entity 00.0005.0000.0000.0001.00
traffic-eng level-2
#
interface Vlanif100
ip address 172.1.1.1 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
isis enable 1
#
interface Tunnel1
ip address unnumbered interface LoopBack1
tunnel-protocol mpls te
destination 3.3.3.9
mpls te tunnel-id 100
mpls te commit
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 100 200
#
mpls lsr-id 2.2.2.9
mpls
mpls te
mpls rsvp-te
#
isis 1
is-level level-2
cost-style wide
network-entity 00.0005.0000.0000.0002.00
traffic-eng level-2
#
interface Vlanif100
ip address 172.1.1.2 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface Vlanif200
ip address 172.2.1.1 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 200
#
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interface LoopBack1
ip address 2.2.2.9 255.255.255.255
isis enable 1
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 200
#
mpls lsr-id 3.3.3.9
mpls
mpls te
mpls rsvp-te
#
isis 1
is-level level-2
cost-style wide
network-entity 00.0005.0000.0000.0003.00
traffic-eng level-2
#
interface Vlanif200
ip address 172.2.1.2 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 200
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
isis enable 1
#
return
6.24.3 Example for Setting Up CR-LSPs Using CR-LSP Attribute
Templates
Networking Requirements
As shown in Figure 6-37, an MPLS TE tunnel is set up between LSRA and LSRC.
The primary path of the tunnel is LSRA -> LSRB -> LSRC. When the primary CRLSP fails, traffic must be switched to a backup CR-LSP.
LSRA needs to set up multiple MPLS TE tunnels to meet service requirements. The
network administrator wants to simplify the MPLS TE tunnel configuration.
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
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Figure 6-37 Networking of CR-LSP setup using CR-LSP attribute templates
Loopback1
6.6.6.9/32
GE0/0/1
VLANIF600
172.6.1.2/24
GE0/0/2
VLANIF600
172.6.1.1/24
Loopback1
1.1.1.9/32
GE0/0/1
VLANIF100
172.1.1.2/24
LSRF
Loopback1
2.2.2.9/32
GE0/0/2
VLANIF700
172.7.1.1/24
GE0/0/3
VLANIF700
172.7.1.2/24
Loopback1
3.3.3.9/32
GE0/0/2
VLANIF200
172.2.1.1/24
LSRA
LSRC
GE0/0/3
VLANIF400
172.4.1.1/24
GE0/0/1
VLANIF100
172.1.1.1/24
LSRB
GE0/0/1
VLANIF200
172.2.1.2/24
GE0/0/2
VLANIF500
172.5.1.2/24
Loopback1
5.5.5.9/32
GE0/0/1
VLANIF400
172.4.1.2/24
Primary CR-LSP
GE0/0/2
VLANIF500
172.5.1.1/24
LSRE
Configuration Roadmap
The configuration roadmap is as follows:
1.
Assign IP addresses to interfaces and configure OSPF to ensure that public
network routes between the nodes are reachable.
2.
Configure LSR IDs for the nodes, enable MPLS, MPLS TE, RSVP-TE, and CSPF
on the LSRs globally and on their interfaces, and enable OSPF TE on the LSRs.
3.
Use CR-LSP attribute templates to simplify the configuration. Configure
different attribute templates for the primary CR-LSP, hot-standby CR-LSP, and
ordinary backup CR-LSP.
4.
On the ingress node of the primary tunnel, create a tunnel interface,
configure the tunnel IP address, tunneling protocol, destination IP address,
tunnel ID, and RSVP-TE signaling protocol for the tunnel interface, and then
apply the corresponding CR-LSP attribute template to set up the primary CRLSP.
5.
Configure hot-standby and ordinary backup CR-LSPs on the ingress node of
the primary tunnel. In this way, traffic can be switched to the backup CR-LSP
when the primary CR-LSP fails. Apply the CR-LSP corresponding attribute
template to create the backup CR-LSP.
Procedure
Step 1 Assign IP addresses to interfaces and configure OSPF on the LSRs.
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6 MPLS TE Configuration
# Configure LSRA. Assign IP addresses to interfaces of LSRB, LSRC, LSRE, and LSRF
according to Figure 6-37. The configurations on these LSRs are similar to the
configuration on LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] vlan batch 100 400 600
[LSRA] interface vlanif 100
[LSRA-Vlanif100] ip address 172.1.1.1 255.255.255.0
[LSRA-Vlanif100] quit
[LSRA] interface vlanif 400
[LSRA-Vlanif400] ip address 172.4.1.1 255.255.255.0
[LSRA-Vlanif400] quit
[LSRA] interface vlanif 600
[LSRA-Vlanif600] ip address 172.6.1.1 255.255.255.0
[LSRA-Vlanif600] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 100
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface gigabitethernet 0/0/2
[LSRA-GigabitEthernet0/0/2] port link-type trunk
[LSRA-GigabitEthernet0/0/2] port trunk allow-pass vlan 600
[LSRA-GigabitEthernet0/0/2] quit
[LSRA] interface gigabitethernet 0/0/3
[LSRA-GigabitEthernet0/0/3] port link-type trunk
[LSRA-GigabitEthernet0/0/3] port trunk allow-pass vlan 400
[LSRA-GigabitEthernet0/0/3] quit
[LSRA] interface loopback 1
[LSRA-LoopBack1] ip address 1.1.1.9 255.255.255.255
[LSRA-LoopBack1] quit
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] network 172.4.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] network 172.6.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
After the configurations are complete, run the display ip routing-table command
on the LSRs. You can see that the LSRs learn the routes to Loopback1 from each
other. The command output on LSRA is provided as an example:
[LSRA] display ip routing-table
Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------Routing Tables: Public
Destinations : 16
Routes : 18
Destination/Mask
Proto Pre Cost
1.1.1.9/32 Direct 0 0
2.2.2.9/32 OSPF 10 1
3.3.3.9/32 OSPF 10 2
OSPF 10 2
OSPF 10 2
5.5.5.9/32 OSPF 10 1
6.6.6.9/32 OSPF 10 1
127.0.0.0/8 Direct 0 0
127.0.0.1/32 Direct 0 0
172.1.1.0/24 Direct 0 0
172.1.1.1/32 Direct 0 0
172.2.1.0/24 OSPF 10 2
172.4.1.0/24 Direct 0 0
172.4.1.1/32 Direct 0 0
172.5.1.0/24 OSPF 10 2
172.6.1.0/24 Direct 0 0
Issue 10 (2019-12-30)
Flags NextHop
Interface
D 127.0.0.1
LoopBack1
D 172.1.1.2
Vlanif100
D 172.1.1.2
Vlanif100
D 172.4.1.2
Vlanif400
D 172.6.1.2
Vlanif600
D 172.4.1.2
Vlanif400
D 172.6.1.2
Vlanif600
D 127.0.0.1
InLoopBack0
D 127.0.0.1
InLoopBack0
D 172.1.1.1
Vlanif100
D 127.0.0.1
Vlanif100
D 172.1.1.2
Vlanif100
D 172.4.1.1
Vlanif400
D 127.0.0.1
Vlanif400
D 172.4.1.2
Vlanif400
D 172.6.1.1
Vlanif600
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172.6.1.1/32 Direct 0 0
172.7.1.0/24 OSPF 10 2
6 MPLS TE Configuration
D 127.0.0.1
D 172.6.1.2
Vlanif600
Vlanif600
Step 2 Configure basic MPLS capabilities and enable MPLS TE, RSVP-TE, and CSPF.
# Configure LSRA. The configurations on LSRB, LSRC, LSRE, and LSRF are similar
to the configuration on LSRA, and are not mentioned here. CSPF needs to be
enabled only on the ingress node of the primary tunnel.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] mpls te
[LSRA-mpls] mpls rsvp-te
[LSRA-mpls] mpls te cspf
[LSRA-mpls] quit
[LSRA] interface vlanif 100
[LSRA-Vlanif100] mpls
[LSRA-Vlanif100] mpls te
[LSRA-Vlanif100] mpls rsvp-te
[LSRA-Vlanif100] quit
[LSRA] interface vlanif 400
[LSRA-Vlanif400] mpls
[LSRA-Vlanif400] mpls te
[LSRA-Vlanif400] mpls rsvp-te
[LSRA-Vlanif400] quit
[LSRA] interface vlanif 600
[LSRA-Vlanif600] mpls
[LSRA-Vlanif600] mpls te
[LSRA-Vlanif600] mpls rsvp-te
[LSRA-Vlanif600] quit
Step 3 Configure OSPF TE.
# Configure LSRA. The configurations on LSRB, LSRC, LSRE, and LSRF are similar
to the configuration on LSRA, and are not mentioned here.
[LSRA] ospf
[LSRA-ospf-1] opaque-capability enable
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] mpls-te enable
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
Step 4 Configure CR-LSP attribute templates and specify explicit paths for the CR-LSPs.
# Specify an explicit path for the primary CR-LSP.
[LSRA] explicit-path pri-path
[LSRA-explicit-path-pri-path] next hop 172.1.1.2
[LSRA-explicit-path-pri-path] next hop 172.2.1.2
[LSRA-explicit-path-pri-path] next hop 3.3.3.9
[LSRA-explicit-path-pri-path] quit
# Specify an explicit path for the hot-standby CR-LSP.
[LSRA] explicit-path hotstandby-path
[LSRA-explicit-path-hotstandby-path] next hop 172.4.1.2
[LSRA-explicit-path-hotstandby-path] next hop 172.5.1.2
[LSRA-explicit-path-hotstandby-path] next hop 3.3.3.9
[LSRA-explicit-path-hotstandby-path] quit
# Specify an explicit path for the ordinary backup CR-LSP.
[LSRA] explicit-path ordinary-path
[LSRA-explicit-path-ordinary-path] next hop 172.6.1.2
[LSRA-explicit-path-ordinary-path] next hop 172.7.1.2
[LSRA-explicit-path-ordinary-path] next hop 3.3.3.9
[LSRA-explicit-path-ordinary-path] quit
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6 MPLS TE Configuration
# Configure the CR-LSP attribute template used for setting up the primary CR-LSP.
[LSRA] lsp-attribute lsp_attribute_pri
[LSRA-lsp-attribute-lsp_attribute_pri] explicit-path pri-path
[LSRA-lsp-attribute-lsp_attribute_pri] commit
[LSRA-lsp-attribute-lsp_attribute_pri] quit
# Configure the CR-LSP attribute template used for setting up the hot-standby CRLSP.
[LSRA] lsp-attribute lsp_attribute_hotstandby
[LSRA-lsp-attribute-lsp_attribute_hotstandby] explicit-path hotstandby-path
[LSRA-lsp-attribute-lsp_attribute_hotstandby] hop-limit 12
[LSRA-lsp-attribute-lsp_attribute_hotstandby] commit
[LSRA-lsp-attribute-lsp_attribute_hotstandby] quit
# Configure the CR-LSP attribute template used for setting up the ordinary backup
CR-LSP.
[LSRA] lsp-attribute lsp_attribute_ordinary
[LSRA-lsp-attribute-lsp_attribute_ordinary] explicit-path ordinary-path
[LSRA-lsp-attribute-lsp_attribute_ordinary] hop-limit 15
[LSRA-lsp-attribute-lsp_attribute_ordinary] commit
[LSRA-lsp-attribute-lsp_attribute_ordinary] quit
Step 5 On the ingress node LSRA, create the MPLS TE tunnel on the primary CR-LSP.
# Specify an MPLS TE tunnel interface for the primary CR-LSP and apply the
primary CR-LSP attribute template to set up this CR-LSP.
[LSRA] interface tunnel 1
[LSRA-Tunnel1] ip address unnumbered interface loopBack 1
[LSRA-Tunnel1] tunnel-protocol mpls te
[LSRA-Tunnel1] destination 3.3.3.9
[LSRA-Tunnel1] mpls te tunnel-id 100
[LSRA-Tunnel1] mpls te primary-lsp-constraint lsp-attribute lsp_attribute_pri
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit
Run the display interface tunnel 1 command on LSRA to check the tunnel status.
The tunnel is in Up state.
[LSRA] display interface tunnel 1
Tunnel1 current state : UP
Line protocol current state : UP
Last line protocol up time : 2013-01-22 16:57:00
Description:
...
Step 6 Configure hot-standby and common backup CR-LSPs on the ingress node.
# On LSRA, apply CR-LSP attribute templates to create hot-standby and common
backup CR-LSPs.
[LSRA] interface tunnel 1
[LSRA-Tunnel1] mpls te hotstandby-lsp-constraint 1 lsp-attribute lsp_attribute_hotstandby
[LSRA-Tunnel1] mpls te ordinary-lsp-constraint 1 lsp-attribute lsp_attribute_ordinary
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit
Run the display mpls te tunnel-interface command on LSRA to check tunnel
information. You can see that the hot-standby CR-LSP has been set up successfully.
[LSRA] display mpls te tunnel-interface
---------------------------------------------------------------Tunnel1
---------------------------------------------------------------Tunnel State Desc : UP
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Active LSP
: Primary LSP
Session ID
: 100
Ingress LSR ID
: 1.1.1.9
Admin State
: UP
Primary LSP State
: UP
Main LSP State
: READY
Hot-Standby LSP State : UP
Main LSP State
: READY
6 MPLS TE Configuration
Egress LSR ID: 3.3.3.9
Oper State : UP
LSP ID : 5
LSP ID : 32772
Step 7 Verify the configuration.
Run the display mpls te tunnel-interface lsp-constraint command on LSRA to
view the configurations of the CR-LSP attribute templates.
[LSRA] display mpls te tunnel-interface lsp-constraint
Tunnel Name
: Tunnel1
Primary-lsp-constraint Name
: lsp_attribute_pri
Hotstandby-lsp-constraint Number: 1
Hotstandby-lsp-constraint Name : lsp_attribute_hotstandby
Ordinary-lsp-constraint Number : 1
Ordinary-lsp-constraint Name : lsp_attribute_ordinary
# Run the display mpls te tunnel verbose command on LSRA to view detailed
tunnel information. You can see that the primary and hot-standby CR-LSPs have
been set up using the attribute templates.
[LSRA] display mpls te tunnel verbose
No
: 1
Tunnel-Name
: Tunnel1
Tunnel Interface Name : Tunnel1
TunnelIndex
: 1
LSP Index
: 2048
Session ID
: 100
LSP ID
: 5
LSR Role
: Ingress
LSP Type
: Primary
Ingress LSR ID
: 1.1.1.9
Egress LSR ID
: 3.3.3.9
In-Interface
: Out-Interface
: Vlanif100
Sign-Protocol
: RSVP TE
Resv Style
: SE
IncludeAnyAff
: 0x0
ExcludeAnyAff
: 0x0
IncludeAllAff
: 0x0
LspConstraint
: 1
ER-Hop Table Index
: 0
AR-Hop Table Index: 0
C-Hop Table Index
: 1
PrevTunnelIndexInSession: 2
NextTunnelIndexInSession: PSB Handle
: 8194
Created Time
: 2013-09-16 14:53:15+00:00
RSVP LSP Type
: -------------------------------DS-TE Information
-------------------------------Bandwidth Reserved Flag : Unreserved
CT0 Bandwidth(Kbit/sec) : 0
CT1 Bandwidth(Kbit/sec): 0
CT2 Bandwidth(Kbit/sec) : 0
CT3 Bandwidth(Kbit/sec): 0
CT4 Bandwidth(Kbit/sec) : 0
CT5 Bandwidth(Kbit/sec): 0
CT6 Bandwidth(Kbit/sec) : 0
CT7 Bandwidth(Kbit/sec): 0
Setup-Priority
: 7
Hold-Priority
: 7
-------------------------------FRR Information
-------------------------------Primary LSP Info
TE Attribute Flag
: 0x3
Protected Flag : 0x0
Bypass In Use
: Not Exists
Bypass Tunnel Id
: BypassTunnel
: Bypass LSP ID
: FrrNextHop
: ReferAutoBypassHandle : FrrPrevTunnelTableIndex : FrrNextTunnelTableIndex: Bypass Attribute(Not configured)
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Setup Priority
: Hold Priority
: HopLimit
: Bandwidth
: IncludeAnyGroup
: ExcludeAnyGroup : IncludeAllGroup
: Bypass Unbound Bandwidth Info(Kbit/sec)
CT0 Unbound Bandwidth : CT1 Unbound Bandwidth:
CT2 Unbound Bandwidth : CT3 Unbound Bandwidth:
CT4 Unbound Bandwidth : CT5 Unbound Bandwidth:
CT6 Unbound Bandwidth : CT7 Unbound Bandwidth:
-------------------------------BFD Information
-------------------------------NextSessionTunnelIndex : PrevSessionTunnelIndex: NextLspId
: PrevLspId
: -
6 MPLS TE Configuration
-
No
: 2
Tunnel-Name
: Tunnel1
Tunnel Interface Name : Tunnel1
TunnelIndex
: 2
LSP Index
: 2050
Session ID
: 100
LSP ID
: 32772
LSR Role
: Ingress
LSP Type
: Hot-Standby
Ingress LSR ID
: 1.1.1.9
Egress LSR ID
: 3.3.3.9
In-Interface
: Out-Interface
: Vlanif400
Sign-Protocol
: RSVP TE
Resv Style
: SE
IncludeAnyAff
: 0x0
ExcludeAnyAff
: 0x0
IncludeAllAff
: 0x0
LspConstraint
: 1
ER-Hop Table Index
: 1
AR-Hop Table Index: 1
C-Hop Table Index
: 2
PrevTunnelIndexInSession: NextTunnelIndexInSession: 1
PSB Handle
: 8195
Created Time
: 2013-09-16 14:53:15+00:00
RSVP LSP Type
: -------------------------------DS-TE Information
-------------------------------Bandwidth Reserved Flag : Unreserved
CT0 Bandwidth(Kbit/sec) : 0
CT1 Bandwidth(Kbit/sec): 0
CT2 Bandwidth(Kbit/sec) : 0
CT3 Bandwidth(Kbit/sec): 0
CT4 Bandwidth(Kbit/sec) : 0
CT5 Bandwidth(Kbit/sec): 0
CT6 Bandwidth(Kbit/sec) : 0
CT7 Bandwidth(Kbit/sec): 0
Setup-Priority
: 7
Hold-Priority
: 7
-------------------------------FRR Information
-------------------------------Primary LSP Info
TE Attribute Flag
: 0x3
Protected Flag : 0x0
Bypass In Use
: Not Exists
Bypass Tunnel Id
: BypassTunnel
: Bypass LSP ID
: FrrNextHop
: ReferAutoBypassHandle : FrrPrevTunnelTableIndex : FrrNextTunnelTableIndex: Bypass Attribute(Not configured)
Setup Priority
: Hold Priority
: HopLimit
: Bandwidth
: IncludeAnyGroup
: ExcludeAnyGroup : IncludeAllGroup
: Bypass Unbound Bandwidth Info(Kbit/sec)
CT0 Unbound Bandwidth : CT1 Unbound Bandwidth: CT2 Unbound Bandwidth : CT3 Unbound Bandwidth: CT4 Unbound Bandwidth : CT5 Unbound Bandwidth: CT6 Unbound Bandwidth : CT7 Unbound Bandwidth: -------------------------------BFD Information
--------------------------------
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NextSessionTunnelIndex : NextLspId
: -
6 MPLS TE Configuration
PrevSessionTunnelIndex: PrevLspId
: -
# Run the shutdown command on GE0/0/1 and GE0/0/3 of LSRA.
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] shutdown
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface gigabitethernet 0/0/3
[LSRA-GigabitEthernet0/0/3] shutdown
[LSRA-GigabitEthernet0/0/3] quit
# Run the display mpls te tunnel verbose command on LSRA. You can see that
an ordinary CR-LSP has been set up using the attribute template.
[LSRA] display mpls te tunnel verbose
No
: 1
Tunnel-Name
: Tunnel1
Tunnel Interface Name : Tunnel1
TunnelIndex
: 2
LSP Index
: 2048
Session ID
: 100
LSP ID
: 32774
LSR Role
: Ingress
LSP Type
: Ordinary
Ingress LSR ID
: 1.1.1.9
Egress LSR ID
: 3.3.3.9
In-Interface
: Out-Interface
: Vlanif600
Sign-Protocol
: RSVP TE
Resv Style
: SE
IncludeAnyAff
: 0x0
ExcludeAnyAff
: 0x0
IncludeAllAff
: 0x0
LspConstraint
: 1
ER-Hop Table Index
: 2
AR-Hop Table Index: 1
C-Hop Table Index
: 2
PrevTunnelIndexInSession: NextTunnelIndexInSession: PSB Handle
: 8196
Created Time
: 2013-09-16 15:00:08+00:00
RSVP LSP Type
: -------------------------------DS-TE Information
-------------------------------Bandwidth Reserved Flag : Unreserved
CT0 Bandwidth(Kbit/sec) : 0
CT1 Bandwidth(Kbit/sec): 0
CT2 Bandwidth(Kbit/sec) : 0
CT3 Bandwidth(Kbit/sec): 0
CT4 Bandwidth(Kbit/sec) : 0
CT5 Bandwidth(Kbit/sec): 0
CT6 Bandwidth(Kbit/sec) : 0
CT7 Bandwidth(Kbit/sec): 0
Setup-Priority
: 7
Hold-Priority
: 7
-------------------------------FRR Information
-------------------------------Primary LSP Info
TE Attribute Flag
: 0x3
Protected Flag : 0x0
Bypass In Use
: Not Exists
Bypass Tunnel Id
: BypassTunnel
: Bypass LSP ID
: FrrNextHop
: ReferAutoBypassHandle : FrrPrevTunnelTableIndex : FrrNextTunnelTableIndex: Bypass Attribute(Not configured)
Setup Priority
: Hold Priority
: HopLimit
: Bandwidth
: IncludeAnyGroup
: ExcludeAnyGroup : IncludeAllGroup
: Bypass Unbound Bandwidth Info(Kbit/sec)
CT0 Unbound Bandwidth : CT1 Unbound Bandwidth: CT2 Unbound Bandwidth : CT3 Unbound Bandwidth: CT4 Unbound Bandwidth : CT5 Unbound Bandwidth: CT6 Unbound Bandwidth : CT7 Unbound Bandwidth: -------------------------------BFD Information
--------------------------------
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NextSessionTunnelIndex : NextLspId
: -
6 MPLS TE Configuration
PrevSessionTunnelIndex: PrevLspId
: -
----End
Configuration File
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 100 400 600
#
mpls lsr-id 1.1.1.9
mpls
mpls te
mpls rsvp-te
mpls te cspf
#
explicit-path hotstandby-path
next hop 172.4.1.2
next hop 172.5.1.2
next hop 3.3.3.9
#
explicit-path ordinary-path
next hop 172.6.1.2
next hop 172.7.1.2
next hop 3.3.3.9
#
explicit-path pri-path
next hop 172.1.1.2
next hop 172.2.1.2
next hop 3.3.3.9
#
lsp-attribute lsp_attribute_hotstandby
explicit-path hotstandby-path
hop-limit 12
commit
#
lsp-attribute lsp_attribute_ordinary
explicit-path ordinary-path
hop-limit 15
commit
#
lsp-attribute lsp_attribute_pri
explicit-path pri-path
commit
#
interface Vlanif100
ip address 172.1.1.1 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface Vlanif400
ip address 172.4.1.1 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface Vlanif600
ip address 172.6.1.1 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
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6 MPLS TE Configuration
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 600
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 400
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
interface Tunnel1
ip address unnumbered interface LoopBack1
tunnel-protocol mpls te
destination 3.3.3.9
mpls te tunnel-id 100
mpls te primary-lsp-constraint lsp-attribute lsp_attribute_pri
mpls te hotstandby-lsp-constraint 1 lsp-attribute lsp_attribute_hotstandby
mpls te ordinary-lsp-constraint 1 lsp-attribute lsp_attribute_ordinary
mpls te record-route
mpls te commit
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.4.1.0 0.0.0.255
network 172.6.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 100 200
#
mpls lsr-id 2.2.2.9
mpls
mpls te
mpls rsvp-te
#
interface Vlanif100
ip address 172.1.1.2 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface Vlanif200
ip address 172.2.1.1 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 200
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
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6 MPLS TE Configuration
ospf 1
opaque-capability enable
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.2.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 200 500 700
#
mpls lsr-id 3.3.3.9
mpls
mpls te
mpls rsvp-te
#
interface Vlanif200
ip address 172.2.1.2 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface Vlanif500
ip address 172.5.1.2 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface Vlanif700
ip address 172.7.1.2 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 200
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 500
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 700
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 172.2.1.0 0.0.0.255
network 172.5.1.0 0.0.0.255
network 172.7.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRE configuration file
#
sysname LSRE
#
vlan batch 400 500
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6 MPLS TE Configuration
#
mpls lsr-id 5.5.5.9
mpls
mpls te
mpls rsvp-te
#
interface Vlanif400
ip address 172.4.1.2 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface Vlanif500
ip address 172.5.1.1 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 400
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 500
#
interface LoopBack1
ip address 5.5.5.9 255.255.255.255
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 5.5.5.9 0.0.0.0
network 172.4.1.0 0.0.0.255
network 172.5.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRF configuration file
#
sysname LSRF
#
vlan batch 600 700
#
mpls lsr-id 6.6.6.9
mpls
mpls te
mpls rsvp-te
#
interface Vlanif600
ip address 172.6.1.2 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface Vlanif700
ip address 172.7.1.1 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 600
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 700
#
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interface LoopBack1
ip address 6.6.6.9 255.255.255.255
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 6.6.6.9 0.0.0.0
network 172.6.1.0 0.0.0.255
network 172.7.1.0 0.0.0.255
mpls-te enable
#
return
6.24.4 Example for Configuring IGP Shortcut to Direct Traffic
to an MPLS TE Tunnel
Networking Requirements
An MPLS TE tunnel does not automatically direct traffic. To direct traffic to an
MPLS TE tunnel, configure Interior Gateway Protocol (IGP) shortcut. IGP shortcut
enables a device to use a TE tunnel as a logical link for IGP route calculation. You
can set a proper metric for an MPLS TE tunnel to ensure that the route passing
through the MPLS TE tunnel is preferred, allowing traffic to be directed to the
MPLS TE tunnel.
As shown in Figure 6-38, devices use OSPF to communicate with each other. An
MPLS TE tunnel is established from LSRA and LSRC. The MPLS TE tunnel passes
through LSRB. The number marked on each link indicates the link cost. If LSRA has
traffic destined for LSRE and LSRC, LSRA sends the traffic to GE0/0/2 based on the
OSPF route selection result. If the link between LSRA and LSRD has 100 Mbit/s of
bandwidth and LSRA requires 50 Mbit/s bandwidth to send traffic to LSRC and 60
Mbit/s bandwidth to send traffic to LSRE, the link between LSRA and LSRB is
congested. Congestion on the link causes traffic transmission delay or packet loss.
To resolve this problem, configure IGP shortcut on the tunnel interface of LSRA to
direct traffic destined for LSRC to the MPLS TE tunnel. By doing this, traffic is
forwarded by GE0/0/1 and network congestion is prevented.
After IGP shortcut is configured on the tunnel interface of LSRA, LSRA does not advertise
the MPLS TE tunnel to its peers as a route. The MPLS TE tunnel is used only for local route
calculation.
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
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Figure 6-38 Networking of IGP shortcut
LSRA
Loopback1
1.1.1.9/32
GE0/0/3
GE0/0/1
GE0/0/2 LSRD VLANIF500
VLANIF500 LSRE
VLANIF400
172.5.1.1/24 172.5.1.2/24
172.4.1.2/24
10
GE0/0/1
10
VLANIF300
GE0/0/2
172.3.1.2/24
VLANIF400
10
172.4.1.1/24
TE Metric=10
GE0/0/1
15
VLANIF100
172.1.1.1/24
GE0/0/2
VLANIF300
172.3.1.1/24
LSRB
GE0/0/1
VLANIF100
172.1.1.2/24
10
LSRC
GE0/0/2
GE0/0/1
VLANIF200 VLANIF200
Loopback1 172.2.1.1/24 172.2.1.2/24 Loopback1
2.2.2.9/32
3.3.3.9/32
Configuration Roadmap
The configuration roadmap is as follows:
1.
Assign an IP address to each interface, configure OSPF to ensure that there
are reachable routes between LSRs, and configure the OSPF cost.
2.
On LSRA, create an MPLS TE tunnel over the path LSRA -> LSRB -> LSRC. This
example uses RSVP-TE to establish a dynamic MPLS TE tunnel. Configure an
ID for each LSR, enable MPLS TE, RSVP-TE, and CSPF on each node and
interface, and enable OSPF TE. On the ingress node of the primary tunnel,
create a tunnel interface, and specify the IP address, tunneling protocol,
destination IP address, tunnel ID, and dynamic signaling protocol RSVP-TE for
the tunnel interface.
3.
Enable IGP shortcut on the TE tunnel interface of LSRA and configure an IGP
metric for the TE tunnel.
Procedure
Step 1 Assign an IP address to each interface, configure OSPF, and set the OSPF cost.
# Configure LSRA. Configure IP addresses for interfaces of LSRB, LSRC, LSRD, and
LSRE according to Figure 6-38. The configurations on LSRB, LSRC, LSRD, and LSRE
are similar to the configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] vlan batch 100 400
[LSRA] interface vlanif 100
[LSRA-Vlanif100] ip address 172.1.1.1 255.255.255.0
[LSRA-Vlanif100] ospf cost 15
[LSRA-Vlanif100] quit
[LSRA] interface vlanif 400
[LSRA-Vlanif400] ip address 172.4.1.1 255.255.255.0
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[LSRA-Vlanif400] ospf cost 10
[LSRA-Vlanif400] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 100
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface gigabitethernet 0/0/2
[LSRA-GigabitEthernet0/0/2] port link-type trunk
[LSRA-GigabitEthernet0/0/2] port trunk allow-pass vlan 400
[LSRA-GigabitEthernet0/0/2] quit
[LSRA] interface loopback 1
[LSRA-LoopBack1] ip address 1.1.1.9 255.255.255.255
[LSRA-LoopBack1] quit
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] network 172.4.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
After the configurations are complete, run the display ip routing-table command
on LSRA, LSRB, and LSRC. You can see that PE1 and PE2 have learned the routes
to Loopback1 of each other.
Step 2 Configure basic MPLS functions and enable MPLS TE, RSVP-TE, and CSPF.
To set up a TE tunnel from LSRA to LSRC, perform the following configurations on
LSRA, LSRB, and LSRC.
# Configure LSRA. The configurations on LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here. CSPF only needs to be
configured on the ingress node of the primary tunnel.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] mpls te
[LSRA-mpls] mpls rsvp-te
[LSRA-mpls] mpls te cspf
[LSRA-mpls] quit
[LSRA] interface vlanif 100
[LSRA-Vlanif100] mpls
[LSRA-Vlanif100] mpls te
[LSRA-Vlanif100] mpls rsvp-te
[LSRA-Vlanif100] quit
Step 3 Configure OSPF TE.
To set up a TE tunnel from LSRA to LSRC, perform the following configurations on
LSRA, LSRB, and LSRC.
# Configure LSRA. The configurations on LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] ospf
[LSRA-ospf-1] opaque-capability enable
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] mpls-te enable
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
Step 4 Create an MPLS TE tunnel.
# Specify an explicit path for a TE tunnel.
[LSRA] explicit-path pri-path
[LSRA-explicit-path-pri-path] next hop 172.1.1.2
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[LSRA-explicit-path-pri-path] next hop 172.2.1.2
[LSRA-explicit-path-pri-path] next hop 3.3.3.9
[LSRA-explicit-path-pri-path] quit
# Create a tunnel interface on LSRA.
[LSRA] interface tunnel 1
[LSRA-Tunnel1] ip address unnumbered interface loopback 1
[LSRA-Tunnel1] tunnel-protocol mpls te
[LSRA-Tunnel1] destination 3.3.3.9
[LSRA-Tunnel1] mpls te tunnel-id 100
[LSRA-Tunnel1] mpls te path explicit-path pri-path
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit
Step 5 Configure IGP shortcut.
Enable IGP shortcut on the TE tunnel interface of LSRA and set the IGP metric to
10 for the TE tunnel.
# Configure LSRA.
[LSRA] interface tunnel 1
[LSRA-Tunnel1] mpls te igp shortcut ospf
[LSRA-Tunnel1] mpls te igp metric absolute 10
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit
[LSRA] ospf 1
[LSRA-ospf-1] enable traffic-adjustment
[LSRA-ospf-1] quit
Step 6 Verify the configuration.
After the configurations are complete, run the display ip routing-table 3.3.3.9
command on LSRA. You can see that the next hop address of the route destined
for LSRC (3.3.3.9) is 1.1.1.9 and the outbound interface of this route is Tunnel1.
The traffic destined for LSRC has been directed to the MPLS TE tunnel.
[LSRA] display ip routing-table 3.3.3.9
Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------Routing Table : Public
Summary Count : 1
Destination/Mask Proto Pre Cost
Flags NextHop
Interface
3.3.3.9/32 OSPF
10 10
D 1.1.1.9
Tunnel1
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 100 400
#
mpls lsr-id 1.1.1.9
mpls
mpls te
mpls rsvp-te
mpls te cspf
#
explicit-path pri-path
next hop 172.1.1.2
next hop 172.2.1.2
next hop 3.3.3.9
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#
interface Vlanif100
ip address 172.1.1.1 255.255.255.0
ospf cost 15
mpls
mpls te
mpls rsvp-te
#
interface Vlanif400
ip address 172.4.1.1 255.255.255.0
ospf cost 10
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 400
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
interface Tunnel1
ip address unnumbered interface LoopBack1
tunnel-protocol mpls te
destination 3.3.3.9
mpls te tunnel-id 100
mpls te path explicit-path pri-path
mpls te igp shortcut ospf
mpls te igp metric absolute 10
mpls te commit
#
ospf 1
opaque-capability enable
enable traffic-adjustment
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.4.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 100 200
#
mpls lsr-id 2.2.2.9
mpls
mpls te
mpls rsvp-te
#
interface Vlanif100
ip address 172.1.1.2 255.255.255.0
ospf cost 15
mpls
mpls te
mpls rsvp-te
#
interface Vlanif200
ip address 172.2.1.1 255.255.255.0
ospf cost 10
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
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port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 200
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.2.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 200 300
#
mpls lsr-id 3.3.3.9
mpls
mpls te
mpls rsvp-te
#
interface Vlanif200
ip address 172.2.1.2 255.255.255.0
ospf cost 10
mpls
mpls te
mpls rsvp-te
#
interface Vlanif300
ip address 172.3.1.1 255.255.255.0
ospf cost 10
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 200
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 300
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 172.2.1.0 0.0.0.255
network 172.3.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRD configuration file
#
sysname LSRD
#
vlan batch 300 400 500
#
interface Vlanif300
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ip address 172.3.1.2 255.255.255.0
ospf cost 10
#
interface Vlanif400
ip address 172.4.1.2 255.255.255.0
ospf cost 10
#
interface Vlanif500
ip address 172.5.1.1 255.255.255.0
ospf cost 10
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 300
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 400
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 500
#
ospf 1
area 0.0.0.0
network 172.3.1.0 0.0.0.255
network 172.4.1.0 0.0.0.255
network 172.5.1.0 0.0.0.255
#
return
●
LSRE configuration file
#
sysname LSRE
#
vlan batch 500
#
interface Vlanif500
ip address 172.5.1.2 255.255.255.0
ospf cost 10
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 500
#
ospf 1
area 0.0.0.0
network 172.5.1.0 0.0.0.255
#
return
6.24.5 Example for Configuring Forwarding Adjacency to
Direct Traffic to an MPLS TE Tunnel
Networking Requirements
An MPLS TE tunnel does not automatically direct traffic. To direct traffic to an
MPLS TE tunnel, configure forwarding adjacency. Forwarding adjacency enables a
device to use a TE tunnel as a logical link for IGP route calculation. Unlike IGP
shortcut, forwarding adjacency advertises a TE tunnel to its peers as an IGP route.
You can set a proper metric for an MPLS TE tunnel to ensure that the route
passing through the MPLS TE tunnel is preferred, allowing traffic to be directed to
the MPLS TE tunnel.
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6 MPLS TE Configuration
As shown in Figure 6-39, devices use OSPF to communicate with each other. An
MPLS TE tunnel is established from LSRA and LSRC. The MPLS TE tunnel passes
through LSRB. The number marked on each link indicates the link cost. If LSRA
and LSRE have traffic destined for LSRC, traffic from the two LSRs is forwarded by
GE0/0/1 on LSRD based on the OSPF route selection result. If LSRA requires 10
Mbit/s bandwidth to send traffic to LSRC, and LSRE requires 100 Mbit/s bandwidth
to send traffic to LSRC, but the link between LSRC and LSRD has only 100 Mbit/s
of bandwidth, the link is congested. Congestion on the link causes traffic
transmission delay or packet loss.
To resolve this problem, configure forwarding adjacency on the MPLS TE tunnel
interface of LSRA. Then all traffic from LSRA to LSRC is forwarded over the MPLS
TE tunnel, whereas only some of traffic from LSRE to LSRC is forwarded over the
MPLS TE tunnel. The rest of traffic is forwarded by LSRD. Therefore, traffic
congestion is prevented over the link between LSRC and LSRD.
After you configure forwarding adjacency, LSRA advertises the MPLS TE tunnel to its peer as
an OSPF route. Because OSPF requires bidirectional link detection, the MPLS TE tunnel from
LSRC to LSRA must be established and forwarding adjacency must be configured on the
tunnel interface.
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
Figure 6-39 Networking of forwarding adjacency
GE0/0/3 LSRD
LSRE GE0/0/1
VLANIF500 VLANIF500
172.5.1.2/24 172.5.1.1/24
10
GE0/0/3
VLANIF600
172.6.1.1/24
Loopback1
1.1.1.9/32
LSRA
GE0/0/1
15
VLANIF100
172.1.1.1/24
GE0/0/1
VLANIF100
172.1.1.2/24
10
GE0/0/2
VLANIF300
172.3.1.1/24
LSRB
Loopback1
2.2.2.9/32
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GE0/0/1
VLANIF300
172.3.1.2/24
10
GE0/0/2
GE0/0/2
VLANIF600 10
VLANIF400
172.6.1.2/24
172.4.1.2/24
GE0/0/2
VLANIF400
172.4.1.1/24
TE Metric=10
10
GE0/0/2
VLANIF200
172.2.1.1/24
Copyright © Huawei Technologies Co., Ltd.
GE0/0/1
VLANIF200
172.2.1.2/24
LSRC
Loopback1
3.3.3.9/32
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6 MPLS TE Configuration
Configuration Roadmap
The configuration roadmap is as follows:
1.
Assign an IP address to each interface, configure OSPF to ensure that there
are reachable routes between LSRs, and configure the OSPF cost.
2.
On LSRA, create an MPLS TE tunnel over the path LSRA -> LSRB -> LSRC. On
LSRC, create an MPLS TE tunnel over the path LSRC -> LSRB -> LSRA. This
example uses RSVP-TE to establish a dynamic MPLS TE tunnel. Configure an
ID for each LSR, enable MPLS TE, RSVP-TE, and CSPF on each node and
interface, and enable OSPF TE. On the ingress node of the primary tunnel,
create a tunnel interface, and specify the IP address, tunneling protocol,
destination IP address, tunnel ID, and dynamic signaling protocol RSVP-TE for
the tunnel interface.
3.
Enable forwarding adjacency on the TE tunnel interfaces of LSRA and LSRC,
and configure the IGP metric for the TE tunnels.
Procedure
Step 1 Assign an IP address to each interface, configure OSPF, and set the OSPF cost.
# Configure LSRA. Configure IP addresses for interfaces of LSRB, LSRC, LSRD, and
LSRE according to Figure 6-39. The configurations on LSRB, LSRC, LSRD, and LSRE
are similar to the configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] vlan batch 100 400 600
[LSRA] interface vlanif 100
[LSRA-Vlanif100] ip address 172.1.1.1 255.255.255.0
[LSRA-Vlanif100] ospf cost 15
[LSRA-Vlanif100] quit
[LSRA] interface vlanif 400
[LSRA-Vlanif400] ip address 172.4.1.1 255.255.255.0
[LSRA-Vlanif400] ospf cost 10
[LSRA-Vlanif400] quit
[LSRA] interface vlanif 600
[LSRA-Vlanif600] ip address 172.6.1.1 255.255.255.0
[LSRA-Vlanif600] ospf cost 10
[LSRA-Vlanif600] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 100
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface gigabitethernet 0/0/2
[LSRA-GigabitEthernet0/0/2] port link-type trunk
[LSRA-GigabitEthernet0/0/2] port trunk allow-pass vlan 400
[LSRA-GigabitEthernet0/0/2] quit
[LSRA] interface gigabitethernet 0/0/3
[LSRA-GigabitEthernet0/0/3] port link-type trunk
[LSRA-GigabitEthernet0/0/3] port trunk allow-pass vlan 600
[LSRA-GigabitEthernet0/0/3] quit
[LSRA] interface loopback 1
[LSRA-LoopBack1] ip address 1.1.1.9 255.255.255.255
[LSRA-LoopBack1] quit
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] network 172.4.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] network 172.6.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
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After the configurations are complete, run the display ip routing-table command
on LSRA, LSRB, and LSRC. You can see that PE1 and PE2 have learned the routes
to Loopback1 interfaces of each other.
Step 2 Configure basic MPLS functions and enable MPLS TE, RSVP-TE, and CSPF.
To create TE tunnels on LSRA and LSRC, perform the following configurations on
LSRA, LSRB, and LSRC.
# Configure LSRA. The configurations on LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here. CSPF only needs to be
configured on the ingress node of the primary tunnel.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] mpls te
[LSRA-mpls] mpls rsvp-te
[LSRA-mpls] mpls te cspf
[LSRA-mpls] quit
[LSRA] interface vlanif 100
[LSRA-Vlanif100] mpls
[LSRA-Vlanif100] mpls te
[LSRA-Vlanif100] mpls rsvp-te
[LSRA-Vlanif100] quit
Step 3 Configure OSPF TE.
To create TE tunnels on LSRA and LSRC, perform the following configurations on
LSRA, LSRB, and LSRC.
# Configure LSRA. The configurations on LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] ospf
[LSRA-ospf-1] opaque-capability enable
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] mpls-te enable
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
Step 4 Create an MPLS TE tunnel.
Create MPLS TE tunnel interfaces on LSRA and LSRC, and configure explicit paths.
# Configure LSRA.
[LSRA] explicit-path pri-path
[LSRA-explicit-path-pri-path] next hop 172.1.1.2
[LSRA-explicit-path-pri-path] next hop 172.2.1.2
[LSRA-explicit-path-pri-path] next hop 3.3.3.9
[LSRA-explicit-path-pri-path] quit
[LSRA] interface tunnel 1
[LSRA-Tunnel1] ip address unnumbered interface loopback 1
[LSRA-Tunnel1] tunnel-protocol mpls te
[LSRA-Tunnel1] destination 3.3.3.9
[LSRA-Tunnel1] mpls te tunnel-id 100
[LSRA-Tunnel1] mpls te path explicit-path pri-path
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit
# Configure LSRC.
[LSRC] explicit-path pri-path
[LSRC-explicit-path-pri-path] next hop 172.2.1.1
[LSRC-explicit-path-pri-path] next hop 172.1.1.1
[LSRC-explicit-path-pri-path] next hop 1.1.1.9
[LSRC-explicit-path-pri-path] quit
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6 MPLS TE Configuration
[LSRC] interface tunnel 1
[LSRC-Tunnel1] ip address unnumbered interface loopback 1
[LSRC-Tunnel1] tunnel-protocol mpls te
[LSRC-Tunnel1] destination 1.1.1.9
[LSRC-Tunnel1] mpls te tunnel-id 101
[LSRC-Tunnel1] mpls te path explicit-path pri-path
[LSRC-Tunnel1] mpls te commit
[LSRC-Tunnel1] quit
Step 5 Configure forwarding adjacency.
Enable forwarding adjacency on the TE tunnel interface of LSRA and set the IGP
metric to 10 for the TE tunnel.
# Configure LSRA.
[LSRA] interface tunnel 1
[LSRA-Tunnel1] mpls te igp advertise
[LSRA-Tunnel1] mpls te igp metric absolute 10
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit
[LSRA] ospf 1
[LSRA-ospf-1] enable traffic-adjustment advertise
[LSRA-ospf-1] quit
# Configure LSRC.
[LSRC] interface tunnel 1
[LSRC-Tunnel1] mpls te igp advertise
[LSRC-Tunnel1] mpls te igp metric absolute 10
[LSRC-Tunnel1] mpls te commit
[LSRC-Tunnel1] quit
[LSRC] ospf 1
[LSRC-ospf-1] enable traffic-adjustment advertise
[LSRC-ospf-1] quit
Step 6 Verify the configuration.
After the configurations are complete, run the display ip routing-table 3.3.3.9
command on LSRA. You can see that the next hop address of the route destined
for LSRC (3.3.3.9) is 1.1.1.9 and the outbound interface of this route is Tunnel1.
The traffic destined for LSRC has been directed to the MPLS TE tunnel.
[LSRA] display ip routing-table 3.3.3.9
Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------Routing Table : Public
Summary Count : 1
Destination/Mask Proto Pre Cost
Flags NextHop
Interface
3.3.3.9/32 OSPF
10 10
D 1.1.1.9
Tunnel1
Run the display ip routing-table 3.3.3.9 command on LSRE. You can see that
there are two equal-cost routes to LSRC (3.3.3.9). Some traffic destined for LSRC is
forwarded by LSRD and some traffic is sent to the LSRA and forwarded over the
MPLS TE tunnel.
[LSRE] display ip routing-table 3.3.3.9
Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------Routing Table : Public
Summary Count : 2
Destination/Mask Proto Pre Cost
Flags NextHop
Interface
3.3.3.9/32 OSPF 10 20
OSPF 10 20
D 172.5.1.1
Vlanif500
D 172.6.1.1
Vlanif600
----End
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Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 100 400 600
#
mpls lsr-id 1.1.1.9
mpls
mpls te
mpls rsvp-te
mpls te cspf
#
explicit-path pri-path
next hop 172.1.1.2
next hop 172.2.1.2
next hop 3.3.3.9
#
interface Vlanif100
ip address 172.1.1.1 255.255.255.0
ospf cost 15
mpls
mpls te
mpls rsvp-te
#
interface Vlanif400
ip address 172.4.1.1 255.255.255.0
ospf cost 10
#
interface Vlanif600
ip address 172.6.1.1 255.255.255.0
ospf cost 10
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 400
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 600
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
interface Tunnel1
ip address unnumbered interface LoopBack1
tunnel-protocol mpls te
destination 3.3.3.9
mpls te tunnel-id 100
mpls te path explicit-path pri-path
mpls te igp advertise
mpls te igp metric absolute 10
mpls te commit
#
ospf 1
opaque-capability enable
enable traffic-adjustment advertise
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.4.1.0 0.0.0.255
network 172.6.1.0 0.0.0.255
mpls-te enable
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#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 100 200
#
mpls lsr-id 2.2.2.9
mpls
mpls te
mpls rsvp-te
#
interface Vlanif100
ip address 172.1.1.2 255.255.255.0
ospf cost 15
mpls
mpls te
mpls rsvp-te
#
interface Vlanif200
ip address 172.2.1.1 255.255.255.0
ospf cost 10
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 200
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.2.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 200 300
#
mpls lsr-id 3.3.3.9
mpls
mpls te
mpls rsvp-te
mpls te cspf
#
explicit-path pri-path
next hop 172.2.1.1
next hop 172.1.1.1
next hop 1.1.1.9
#
interface Vlanif200
ip address 172.2.1.2 255.255.255.0
ospf cost 10
mpls
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mpls te
mpls rsvp-te
#
interface Vlanif300
ip address 172.3.1.1 255.255.255.0
ospf cost 10
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 200
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 300
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
interface Tunnel1
ip address unnumbered interface LoopBack1
tunnel-protocol mpls te
destination 1.1.1.9
mpls te tunnel-id 101
mpls te path explicit-path pri-path
mpls te igp advertise
mpls te igp metric absolute 10
mpls te commit
#
ospf 1
opaque-capability enable
enable traffic-adjustment advertise
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 172.2.1.0 0.0.0.255
network 172.3.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRD configuration file
#
sysname LSRD
#
vlan batch 300 400 500
#
interface Vlanif300
ip address 172.3.1.2 255.255.255.0
ospf cost 10
#
interface Vlanif400
ip address 172.4.1.2 255.255.255.0
ospf cost 10
#
interface Vlanif500
ip address 172.5.1.1 255.255.255.0
ospf cost 10
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 300
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 400
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 500
#
ospf 1
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area 0.0.0.0
network 172.3.1.0 0.0.0.255
network 172.4.1.0 0.0.0.255
network 172.5.1.0 0.0.0.255
#
return
●
LSRE configuration file
#
sysname LSRE
#
vlan batch 500 600
#
interface Vlanif500
ip address 172.5.1.2 255.255.255.0
ospf cost 10
#
interface Vlanif600
ip address 172.6.1.2 255.255.255.0
ospf cost 10
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 500
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 600
#
ospf 1
area 0.0.0.0
network 172.5.1.0 0.0.0.255
network 172.6.1.0 0.0.0.255
#
return
6.24.6 Example for Setting Attributes for an MPLS TE Tunnel
Networking Requirements
As shown in Figure 6-40, LSRA has two dynamic MPLS TE tunnels to LSRD:
Tunnel1 and Tunnel2. The affinity attribute and mask need to be used according
to the administrative group attribute so that Tunnel1 on LSRA uses the physical
link LSRA -> LSRB -> LSRC -> LSRD and Tunnel2 uses the physical link LSRA ->
LSRB -> LSRE -> LSRC -> LSRD.
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
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Figure 6-40 Networking for setting MPLS TE tunnel attributes
Loopback1
4.4.4.9/32
LSRD
GE0/0/1
VLANIF300
172.3.1.2/24
Loopback1
1.1.1.9/32 GE0/0/1
VLANIF100
172.1.1.1/24
Loopback1
2.2.2.9/32 GE0/0/2
VLANIF200
172.2.1.1/24
GE0/0/1
VLANIF100
172.1.1.2/24 GE0/0/3
VLANIF400
172.4.1.1/24
LSRA
Path of Tunnel 1
Path of Tunnel 2
LSRB
GE0/0/2
VLANIF300
172.3.1.1/24
GE0/0/1
VLANIF200
172.2.1.2/24
Loopback1
5.5.5.9/32
GE0/0/1
VLANIF400
172.4.1.2/24
Loopback1
3.3.3.9/32
LSRC
GE0/0/3
VLANIF500
172.5.1.2/24
GE0/0/2
VLANIF500
172.5.1.1/24
LSRE
Configuration Roadmap
The configuration roadmap is as follows:
1.
Assign an IP address to each interface and configure OSPF to ensure that
there are reachable routes between LSRs.
2.
Configure an ID for each LSR and globally enable MPLS TE, RSVP-TE, CSPF on
each node and interface, and enable OSPF TE.
3.
Configure the administrative group attribute of the outbound interface of the
tunnel on each LSR.
4.
On the ingress node of the primary tunnel, create a tunnel interface, and
specify the IP address, tunneling protocol, destination IP address, tunnel ID,
and dynamic signaling protocol RSVP-TE for the tunnel interface.
5.
Determine and configure the affinity attribute and mask for each tunnel
according to the administrative group attribute and networking requirements.
Procedure
Step 1 Assign an IP address to each interface and configure OSPF.
# Configure LSRA. Configure IP addresses for interfaces of LSRB, LSRC, LSRD, and
LSRE according to Figure 6-40. The configurations of LSRB, LSRC, LSRD, and LSRE
are similar to the configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] vlan batch 100
[LSRA] interface vlanif 100
[LSRA-Vlanif100] ip address 172.1.1.1 255.255.255.0
[LSRA-Vlanif100] quit
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[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 100
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface loopback 1
[LSRA-LoopBack1] ip address 1.1.1.9 255.255.255.255
[LSRA-LoopBack1] quit
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
After the configurations are complete, run the display ip routing-table command
on each LSR. You can see that the LSRs have learned the routes to Loopback1
interfaces of each other. The display on LSRA is used as an example.
[LSRA] display ip routing-table
Route Flags: R - relay, D - download to fib
-----------------------------------------------------------------------------Routing Tables: Public
Destinations : 13
Routes : 13
Destination/Mask
Proto Pre Cost
1.1.1.9/32 Direct 0 0
2.2.2.9/32 OSPF 10 1
3.3.3.9/32 OSPF 10 2
4.4.4.9/32 OSPF 10 3
5.5.5.9/32 OSPF 10 2
127.0.0.0/8 Direct 0 0
127.0.0.1/32 Direct 0 0
172.1.1.0/24 Direct 0 0
172.1.1.1/32 Direct 0 0
172.2.1.0/24 OSPF 10 2
172.3.1.0/24 OSPF 10 3
172.4.1.0/24 OSPF 10 2
172.5.1.0/24 OSPF 10 3
Flags NextHop
D 127.0.0.1
D 172.1.1.2
D 172.1.1.2
D 172.1.1.2
D 172.1.1.2
D 127.0.0.1
D 127.0.0.1
D 172.1.1.1
D 127.0.0.1
D 172.1.1.2
D 172.1.1.2
D 172.1.1.2
D 172.1.1.2
Interface
LoopBack1
Vlanif100
Vlanif100
Vlanif100
Vlanif100
InLoopBack0
InLoopBack0
Vlanif100
Vlanif100
Vlanif100
Vlanif100
Vlanif100
Vlanif100
Step 2 Configure basic MPLS functions and enable MPLS TE, RSVP-TE, and CSPF.
# Configure LSRA. The configurations of LSRB, LSRC, LSRD, and LSRE are similar to
the configuration of LSRA, and are not mentioned here. CSPF only needs to be
configured on the ingress node of the primary tunnel.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] mpls te
[LSRA-mpls] mpls rsvp-te
[LSRA-mpls] mpls te cspf
[LSRA-mpls] quit
[LSRA] interface vlanif 100
[LSRA-Vlanif100] mpls
[LSRA-Vlanif100] mpls te
[LSRA-Vlanif100] mpls rsvp-te
[LSRA-Vlanif100] quit
Step 3 Configure OSPF TE.
# Configure LSRA. The configurations of LSRB, LSRC, LSRD, and LSRE are similar to
the configuration of LSRA, and are not mentioned here.
[LSRA] ospf
[LSRA-ospf-1] opaque-capability enable
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] mpls-te enable
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
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Step 4 Set MPLS TE attributes of the outbound interface of each node.
# Configure the administrative group attribute on LSRA.
[LSRA] interface vlanif 100
[LSRA-Vlanif100] mpls te link administrative group 10001
[LSRA-Vlanif100] quit
# Configure the administrative group attribute on LSRB.
[LSRB] interface vlanif 200
[LSRB-Vlanif200] mpls te link administrative group 10101
[LSRB-Vlanif200] quit
[LSRB] interface vlanif 400
[LSRB-Vlanif400] mpls te link administrative group 10011
[LSRB-Vlanif400] quit
# Configure the administrative group attribute on LSRC.
[LSRC] interface vlanif 300
[LSRC-Vlanif300] mpls te link administrative group 10001
[LSRC-Vlanif300] quit
# Configure the administrative group attribute on LSRE.
[LSRE] interface vlanif 500
[LSRE-Vlanif500] mpls te link administrative group 10011
[LSRE-Vlanif500] quit
After the configurations are complete, check the TEDB including the Color field of
each link. The Color field indicates the administrative group attribute. The display
on LSRA is used as an example.
[LSRA] display mpls te cspf tedb node
Router ID: 1.1.1.9
IGP Type: OSPF
Process ID: 1
MPLS-TE Link Count: 1
Link[1]:
OSPF Router ID: 1.1.1.9
Opaque LSA ID: 1.0.0.1
Interface IP Address: 172.1.1.1
DR Address: 172.1.1.1
IGP Area: 0
Link Type: Multi-access Link Status: Active
IGP Metric: 1
TE Metric: 1
Color: 0x10001
...
Step 5 Create MPLS TE tunnels on the ingress node.
# Create Tunnel1 on LSRA.
[LSRA] interface tunnel 1
[LSRA-Tunnel1] ip address unnumbered interface loopback 1
[LSRA-Tunnel1] tunnel-protocol mpls te
[LSRA-Tunnel1] destination 4.4.4.9
[LSRA-Tunnel1] mpls te tunnel-id 100
[LSRA-Tunnel1] mpls te record-route label
[LSRA-Tunnel1] mpls te affinity property 10101 mask 11011
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit
# Create Tunnel2 on LSRA.
[LSRA] interface tunnel 2
[LSRA-Tunnel2] ip address unnumbered interface loopback 1
[LSRA-Tunnel2] tunnel-protocol mpls te
[LSRA-Tunnel2] destination 4.4.4.9
[LSRA-Tunnel2] mpls te tunnel-id 101
[LSRA-Tunnel2] mpls te record-route label
[LSRA-Tunnel2] mpls te affinity property 10011 mask 11101
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[LSRA-Tunnel2] mpls te commit
[LSRA-Tunnel2] quit
Step 6 Verify the configuration.
After the configurations are complete, run the display mpls te tunnel-interface
command to view the tunnel status on LSRA. You can see that both Tunnel1 and
Tunnel2 are Up.
[LSRA] display mpls te tunnel-interface
---------------------------------------------------------------Tunnel1
---------------------------------------------------------------Tunnel State Desc : UP
Active LSP
: Primary LSP
Session ID
: 100
Ingress LSR ID
: 1.1.1.9
Egress LSR ID: 4.4.4.9
Admin State
: UP
Oper State : UP
Primary LSP State
: UP
Main LSP State
: READY
LSP ID : 47
---------------------------------------------------------------Tunnel2
---------------------------------------------------------------Tunnel State Desc : UP
Active LSP
: Primary LSP
Session ID
: 101
Ingress LSR ID
: 1.1.1.9
Egress LSR ID: 4.4.4.9
Admin State
: UP
Oper State : UP
Primary LSP State
: UP
Main LSP State
: READY
LSP ID : 4
Run the display mpls te tunnel path command to view the path of the tunnel.
You can see that the affinity attribute and mask of the tunnel match the
administrative group attribute of each link.
[LSRA] display mpls te tunnel path
Tunnel Interface Name : Tunnel1
Lsp ID : 1.1.1.9 :100 :47
Hop Information
Hop 0 172.1.1.1
Hop 1 172.1.1.2 Label 1065
Hop 2 2.2.2.9 Label 1065
Hop 3 172.2.1.1
Hop 4 172.2.1.2 Label 1075
Hop 5 3.3.3.9 Label 1075
Hop 6 172.3.1.1
Hop 7 172.3.1.2 Label 3
Hop 8 4.4.4.9 Label 3
Tunnel Interface Name : Tunnel2
Lsp ID : 1.1.1.9 :101 :4
Hop Information
Hop 0 172.1.1.1
Hop 1 172.1.1.2 Label 1067
Hop 2 2.2.2.9 Label 1067
Hop 3 172.4.1.1
Hop 4 172.4.1.2 Label 1040
Hop 5 5.5.5.9 Label 1040
Hop 6 172.5.1.1
Hop 7 172.5.1.2 Label 1077
Hop 8 3.3.3.9 Label 1077
Hop 9 172.3.1.1
Hop 10 172.3.1.2 Label 3
Hop 11 4.4.4.9 Label 3
----End
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Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 100
#
mpls lsr-id 1.1.1.9
mpls
mpls te
mpls rsvp-te
mpls te cspf
#
interface Vlanif100
ip address 172.1.1.1 255.255.255.0
mpls
mpls te
mpls te link administrative group 10001
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
#
interface Tunnel1
ip address unnumbered interface LoopBack1
tunnel-protocol mpls te
destination 4.4.4.9
mpls te tunnel-id 100
mpls te record-route label
mpls te affinity property 10101 mask 11011
mpls te commit
#
interface Tunnel2
ip address unnumbered interface LoopBack1
tunnel-protocol mpls te
destination 4.4.4.9
mpls te tunnel-id 101
mpls te record-route label
mpls te affinity property 10011 mask 11101
mpls te commit
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 1.1.1.9 0.0.0.0
network 172.1.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 100 200 400
#
mpls lsr-id 2.2.2.9
mpls
mpls te
mpls rsvp-te
#
interface Vlanif100
ip address 172.1.1.2 255.255.255.0
mpls
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mpls te
mpls rsvp-te
#
interface Vlanif200
ip address 172.2.1.1 255.255.255.0
mpls
mpls te
mpls te link administrative group 10101
mpls rsvp-te
#
interface Vlanif400
ip address 172.4.1.1 255.255.255.0
mpls
mpls te
mpls te link administrative group 10011
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 200
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 400
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 2.2.2.9 0.0.0.0
network 172.1.1.0 0.0.0.255
network 172.2.1.0 0.0.0.255
network 172.4.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 200 300 500
#
mpls lsr-id 3.3.3.9
mpls
mpls te
mpls rsvp-te
#
interface Vlanif200
ip address 172.2.1.2 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface Vlanif300
ip address 172.3.1.1 255.255.255.0
mpls
mpls te
mpls te link administrative group 10001
mpls rsvp-te
#
interface Vlanif500
ip address 172.5.1.2 255.255.255.0
mpls
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mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 200
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 300
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 500
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 3.3.3.9 0.0.0.0
network 172.2.1.0 0.0.0.255
network 172.3.1.0 0.0.0.255
network 172.5.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRD configuration file
#
sysname LSRD
#
vlan batch 300
#
mpls lsr-id 4.4.4.9
mpls
mpls te
mpls rsvp-te
#
interface Vlanif300
ip address 172.3.1.2 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 300
#
interface LoopBack1
ip address 4.4.4.9 255.255.255.255
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 4.4.4.9 0.0.0.0
network 172.3.1.0 0.0.0.255
mpls-te enable
#
return
●
LSRE configuration file
#
sysname LSRE
#
vlan batch 400 500
#
mpls lsr-id 5.5.5.9
mpls
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mpls te
mpls rsvp-te
#
interface Vlanif400
ip address 172.4.1.2 255.255.255.0
mpls
mpls te
mpls rsvp-te
#
interface Vlanif500
ip address 172.5.1.1 255.255.255.0
mpls
mpls te
mpls te link administrative group 10011
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 400
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 500
#
interface LoopBack1
ip address 5.5.5.9 255.255.255.255
#
ospf 1
opaque-capability enable
area 0.0.0.0
network 5.5.5.9 0.0.0.0
network 172.4.1.0 0.0.0.255
network 172.5.1.0 0.0.0.255
mpls-te enable
#
return
6.24.7 Example for Configuring Srefresh Based on Manual TE
FRR
Networking Requirements
As shown in Figure 6-41, the primary CR-LSP is along the path LSRA -> LSRB ->
LSRC -> LSRD, and the link between LSRB and LSRC needs to be protected by FRR.
A bypass CR-LSP is set up along the path LSRB -> LSRE -> LSRC. LSRB functions as
the PLR and LSRC functions as the MP.
The primary and bypass MPLS TE tunnels are set up by using explicit paths. RSVPTE is used as the signaling protocol.
The Srefresh function needs to be configured on LSRB and LSRC.
In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and
connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of
switches are used to construct a Layer 3 ring network, an interface on the network will be
blocked. As a result, Layer 3 services on the network cannot run normally.
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Figure 6-41 Networking for configuring Srefresh based on manual TE FRR
Loopback1
4.4.4.9/32
LSRD
GE0/0/1
VLANIF300
172.3.1.2/24
Loopback1
1.1.1.9/32 GE0/0/1
VLANIF100
172.1.1.1/24
Loopback1
2.2.2.9/32 GE0/0/2
VLANIF200
172.2.1.1/24
GE0/0/1
VLANIF100
172.1.1.2/24
LSRA
LSRB
GE0/0/3
VLANIF400
172.4.1.1/24
Primary CR-LSP
Bypass CR-LSP
GE0/0/2
VLANIF300
172.3.1.1/24
GE0/0/1
VLANIF200
172.2.1.2/24
Loopback1
5.5.5.9/32
GE0/0/1
VLANIF400
172.4.1.2/24
Loopback1
3.3.3.9/32
LSRC
GE0/0/3
VLANIF500
172.5.1.2/24
GE0/0/2
VLANIF500
172.5.1.1/24
LSRE
Configuration Roadmap
The configuration roadmap is as follows:
1.
Configure manual TE FRR.
2.
Configure Srefresh on the PLR and MP along a tunnel to enhance
transmission reliability of RSVP messages and improve resource use efficiency.
Procedure
Step 1 Configure manual TE FRR.
Configure the primary and bypass MPLS TE tunnels according to 6.24.13 Example
for Configuring Manual TE FRR, and then bind the two tunnels.
Step 2 Configure the Srefresh function on LSRB and LSRC.
# Configure the Srefresh function on LSRB.
[LSRB] mpls
[LSRB-mpls] mpls rsvp-te srefresh
[LSRB-mpls] quit
# Configure the Srefresh function on LSRC.
[LSRC] mpls
[LSRC-mpls] mpls rsvp-te srefresh
[LSRC-mpls] quit
Step 3 Verify the configuration.
# Run the display mpls rsvp-te statistics global command on LSRB. You can
view the status of the Srefresh function. If the command output shows that the
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values of SendSrefreshCounter, RecSrefreshCounter, SendAckMsgCounter, and
RecAckMsgCounter are not zero, Srefresh packets are successfully transmitted.
[LSRB] display mpls rsvp-te statistics global
LSR ID: 2.2.2.9
LSP Count: 2
PSB Count: 2
RSB Count: 2
RFSB Count: 1
Total Statistics Information:
PSB CleanupTimeOutCounter: 0
RSB CleanupTimeOutCounter: 0
SendPacketCounter: 122613
RecPacketCounter: 127446
SendCreatePathCounter: 25
RecCreatePathCounter: 260
SendRefreshPathCounter: 62209
RecRefreshPathCounter: 62113
SendCreateResvCounter: 21
RecCreateResvCounter: 31
SendRefreshResvCounter: 60101
RecRefreshResvCounter: 64792
SendResvConfCounter: 0
RecResvConfCounter: 0
SendHelloCounter: 0
RecHelloCounter: 0
SendAckCounter: 0
RecAckCounter: 0
SendPathErrCounter: 242
RecPathErrCounter: 0
SendResvErrCounter: 0
RecResvErrCounter: 0
SendPathTearCounter: 11
RecPathTearCounter: 8
SendResvTearCounter: 2
RecResvTearCounter: 0
SendSrefreshCounter: 1
RecSrefreshCounter: 1
SendAckMsgCounter: 1
RecAckMsgCounter: 1
SendChallengeMsgCounter: 0
RecChallengeMsgCounter: 0
SendResponseMsgCounter: 0
RecResponseMsgCounter: 0
SendErrMsgCounter: 0
RecErrMsgCounter: 0
SendRecoveryPathMsgCounter: 0
RecRecoveryPathMsgCounter: 0
SendGRPathMsgCounter: 0
RecGRPathMsgCounter: 0
ResourceReqFaultCounter: 0
RecGRPathMsgFromLSPMCounter: 0
Bfd neighbor count: 3
Bfd session count: 0
# Shut down the protected outbound interface VLANIF200 on LSRB.
[LSRB] interface vlanif 200
[LSRB-Vlanif200] shutdown
[LSRB-Vlanif200] quit
Run the display interface tunnel 1 command on LSRA. You can view the status of
the primary CR-LSP and that the status of the tunnel interface is still Up.
[LSRA] display interface tunnel 1
Tunnel1 current state : UP
Line protocol current state : UP
Last line protocol up time : 2013-01-21 10:58:49
Description:
...
Run the tracert lsp te tunnel 1 command on LSRA. You can view the path that
the tunnel passes.
[LSRA] tracert lsp te tunnel 1
LSP Trace Route FEC: TE TUNNEL IPV4 SESSION QUERY Tunnel1 , press CTRL_C t
o break.
TTL Replier
Time Type
Downstream
0
Ingress 172.1.1.2/[1034 ]
1
172.1.1.2
1 ms Transit 172.4.1.2/[1042 1025 ]
2
172.4.1.2
1 ms Transit 172.5.1.2/[3 ]
3
172.5.1.2
2 ms Transit 172.3.1.2/[3 ]
4
4.4.4.9
2 ms Egress
The preceding information shows that services on the link have been switched to
the bypass CR-LSP.
Run the display mpls te tunnel name Tunnel1 verbose command on LSRB. You
can see that the bypass CR-LSP is in use.
[LSRB] display mpls te tunnel name Tunnel1 verbose
No
: 1
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Tunnel-Name
: Tunnel1
Tunnel Interface Name : TunnelIndex
: 1
LSP Index
: 2048
Session ID
: 100
LSP ID
: 5
LSR Role
: Transit
Ingress LSR ID
: 1.1.1.9
Egress LSR ID
: 4.4.4.9
In-Interface
: Vlanif100
Out-Interface
: Vlanif200
Sign-Protocol
: RSVP TE
Resv Style
: SE
IncludeAnyAff
: 0x0
ExcludeAnyAff
: 0x0
IncludeAllAff
: 0x0
ER-Hop Table Index
: AR-Hop Table Index: 0
C-Hop Table Index
: PrevTunnelIndexInSession: NextTunnelIndexInSession: PSB Handle
: 8421
Created Time
: 2013-09-16 18:27:55+00:00
RSVP LSP Type
: -------------------------------DS-TE Information
-------------------------------Bandwidth Reserved Flag : Unreserved
CT0 Bandwidth(Kbit/sec) : 0
CT1 Bandwidth(Kbit/sec): 0
CT2 Bandwidth(Kbit/sec) : 0
CT3 Bandwidth(Kbit/sec): 0
CT4 Bandwidth(Kbit/sec) : 0
CT5 Bandwidth(Kbit/sec): 0
CT6 Bandwidth(Kbit/sec) : 0
CT7 Bandwidth(Kbit/sec): 0
Setup-Priority
: 7
Hold-Priority
: 7
-------------------------------FRR Information
-------------------------------Primary LSP Info
TE Attribute Flag
: 0x63
Protected Flag : 0x1
Bypass In Use
: In Use
Bypass Tunnel Id
: 1225021547
BypassTunnel
: Tunnel Index[Tunnel2], InnerLabel[1042]
Bypass LSP ID
: 2
FrrNextHop
: 172.5.1.2
ReferAutoBypassHandle : FrrPrevTunnelTableIndex : FrrNextTunnelTableIndex: Bypass Attribute(Not configured)
Setup Priority
: Hold Priority
: HopLimit
: Bandwidth
: IncludeAnyGroup
: ExcludeAnyGroup : IncludeAllGroup
: Bypass Unbound Bandwidth Info(Kbit/sec)
CT0 Unbound Bandwidth : CT1 Unbound Bandwidth: CT2 Unbound Bandwidth : CT3 Unbound Bandwidth: CT4 Unbound Bandwidth : CT5 Unbound Bandwidth: CT6 Unbound Bandwidth : CT7 Unbound Bandwidth: -------------------------------BFD Information
-------------------------------NextSessionTunnelIndex : PrevSessionTunnelIndex: NextLspId
: PrevLspId
: -
Run the display mpls rsvp-te statistics global command on LSRB to view
Srefresh statistics.
[LSRB] display mpls rsvp-te statistics global
LSR ID: 2.2.2.9
LSP Count: 2
PSB Count: 2
RSB Count: 2
RFSB Count: 1
Total Statistics Information:
PSB CleanupTimeOutCounter: 0
SendPacketCounter: 122707
SendCreatePathCounter: 27
SendRefreshPathCounter: 62220
SendCreateResvCounter: 22
SendRefreshResvCounter: 60111
SendResvConfCounter: 0
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RSB CleanupTimeOutCounter: 0
RecPacketCounter: 127580
RecCreatePathCounter: 304
RecRefreshPathCounter: 62122
RecCreateResvCounter: 32
RecRefreshResvCounter: 64803
RecResvConfCounter: 0
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SendHelloCounter: 0
SendAckCounter: 0
SendPathErrCounter: 287
SendResvErrCounter: 0
SendPathTearCounter: 11
SendResvTearCounter: 2
SendSrefreshCounter: 13
SendAckMsgCounter: 14
SendChallengeMsgCounter: 0
SendResponseMsgCounter: 0
SendErrMsgCounter: 0
SendRecoveryPathMsgCounter:
SendGRPathMsgCounter: 0
ResourceReqFaultCounter: 0
Bfd neighbor count: 2
6 MPLS TE Configuration
RecHelloCounter: 0
RecAckCounter: 0
RecPathErrCounter: 0
RecResvErrCounter: 0
RecPathTearCounter: 8
RecResvTearCounter: 0
RecSrefreshCounter: 14
RecAckMsgCounter: 13
RecChallengeMsgCounter: 0
RecResponseMsgCounter: 0
RecErrMsgCounter: 0
0
RecRecoveryPathMsgCounter: 0
RecGRPathMsgCounter: 0
RecGRPathMsgFromLSPMCounter: 0
Bfd session count: 0
Because the Srefresh function is configured globally on LSRB and LSRC, the
Srefresh function takes effect on LSRB and LSRC when the primary tunnel fails.
----End
Configuration Files
●
LSRA configuration file
#
sysname LSRA
#
vlan batch 100
#
mpls lsr-id 1.1.1.9
mpls
mpls te
mpls rsvp-te
mpls te cspf
#
explicit-path pri-path
next hop 172.1.1.2
next hop 172.2.1.2
next hop 172.3.1.2
next hop 4.4.4.9
#
isis 1
is-level level-2
cost-style wide
network-entity 00.0005.0000.0000.0001.00
traffic-eng level-2
#
interface Vlanif100
ip address 172.1.1.1 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface LoopBack1
ip address 1.1.1.9 255.255.255.255
isis enable 1
#
interface Tunnel1
ip address unnumbered interface LoopBack1
tunnel-protocol mpls te
destination 4.4.4.9
mpls te tunnel-id 100
mpls te record-route label
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mpls te path explicit-path pri-path
mpls te fast-reroute
mpls te commit
#
return
●
LSRB configuration file
#
sysname LSRB
#
vlan batch 100 200 400
#
mpls lsr-id 2.2.2.9
mpls
mpls te
mpls te timer fast-reroute 120
mpls rsvp-te
mpls rsvp-te srefresh
mpls te cspf
#
explicit-path by-path
next hop 172.4.1.2
next hop 172.5.1.2
next hop 3.3.3.9
#
isis 1
is-level level-2
cost-style wide
network-entity 00.0005.0000.0000.0002.00
traffic-eng level-2
#
interface Vlanif100
ip address 172.1.1.2 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface Vlanif200
ip address 172.2.1.1 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface Vlanif400
ip address 172.4.1.1 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 100
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 200
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 400
#
interface LoopBack1
ip address 2.2.2.9 255.255.255.255
isis enable 1
#
interface Tunnel2
ip address unnumbered interface LoopBack1
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tunnel-protocol mpls te
destination 3.3.3.9
mpls te tunnel-id 300
mpls te record-route
mpls te path explicit-path by-path
mpls te bypass-tunnel
mpls te protected-interface Vlanif200
mpls te commit
#
return
●
LSRC configuration file
#
sysname LSRC
#
vlan batch 200 300 500
#
mpls lsr-id 3.3.3.9
mpls
mpls te
mpls rsvp-te
mpls rsvp-te srefresh
#
isis 1
is-level level-2
cost-style wide
network-entity 00.0005.0000.0000.0003.00
traffic-eng level-2
#
interface Vlanif200
ip address 172.2.1.2 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface Vlanif300
ip address 172.3.1.1 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface Vlanif500
ip address 172.5.1.2 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 200
#
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 300
#
interface GigabitEthernet0/0/3
port link-type trunk
port trunk allow-pass vlan 500
#
interface LoopBack1
ip address 3.3.3.9 255.255.255.255
isis enable 1
#
return
●
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LSRD configuration file
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#
sysname LSRD
#
vlan batch 300
#
mpls lsr-id 4.4.4.9
mpls
mpls te
mpls rsvp-te
#
isis 1
is-level level-2
cost-style wide
network-entity 00.0005.0000.0000.0004.00
traffic-eng level-2
#
interface Vlanif300
ip address 172.3.1.2 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 300
#
interface LoopBack1
ip address 4.4.4.9 255.255.255.255
isis enable 1
#
return
●
LSRE configuration file
#
sysname LSRE
#
vlan batch 400 500
#
mpls lsr-id 5.5.5.9
mpls
mpls te
mpls rsvp-te
#
isis 1
is-level level-2
cost-style wide
network-entity 00.0005.0000.0000.0005.00
traffic-eng level-2
#
interface Vlanif400
ip address 172.4.1.2 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface Vlanif500
ip address 172.5.1.1 255.255.255.0
isis enable 1
mpls
mpls te
mpls rsvp-te
#
interface GigabitEthernet0/0/1
port link-type trunk
port trunk allow-pass vlan 400
#
interface GigabitEthernet0/0/2
port link-type trunk
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port trunk allow-pass vlan 500
#
interface LoopBack1
ip address 5.5.5.9 255.255.255.255
isis enable 1
#
return
6.24.8 Example for Configuring RSVP Authentication
Networking Requirements
As shown in Figure 6-42, VLANIF100 between LSRA and LSRB contains member
interfaces GE0/0/1 and GE0/0/2. An MPLS TE tunnel from LSRA to LSRC is set up
by using RSVP.
The handshake function needs to be configured so that LSRA and LSRB perform
RSPV authentication to prevent forged Resv messages from consuming network
resources. In addition, the message window function is configured to solve the
problem of RSVP packet mis-sequencing.
Figure 6-42 Networking of RSVP authentication
Loopback1
1.1.1.9/32
VLANIF100
172.1.1.1/24
LSRA GE0/0/1
GE0/0/2
Loopback1
2.2.2.9/32
GE0/0/3
VLANIF100
VLANIF200
172.1.1.2/24
172.2.1.1/24
GE0/0/1
LSRB
GE0/0/2
Loopback1
3.3.3.9/32
GE0/0/1
VLANIF200 LSRC
172.2.1.2/24
Configuration Roadmap
The configuration roadmap is as follows:
1.
Assign an IP address to each interface on each LSR and configure OSPF to
ensure that there are reachable routes between LSRs.
2.
Configure an ID for each LSR and globally enable MPLS, MPLS TE, and RSVPTE on each node and interface.
3.
On the ingress node, create a tunnel interface, and specify the IP address,
tunneling protocol, destination IP address, tunnel ID, and dynamic signaling
protocol RSVP-TE, and enable CSPF.
4.
Configure RSVP authentication on LSRA and LSRB of the tunnel.
5.
Configure the Handshake function on LSRA and LSRB to prevent forged Resv
messages from consuming network resources.
6.
Configure the sliding window function on LSRA and LSRB to solve the
problem of RSVP packet mis-sequencing.
It is recommended that the window size be larger than 32. If the window size is too small,
some received RSVP messages may be discarded, which can terminate the RSVP neighbor
relationships.
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Procedure
Step 1 Assign an IP address to each interface and configure OSPF.
# Configure LSRA. Configure IP addresses for interfaces of LSRB and LSRC
according to Figure 6-42. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] vlan batch 100
[LSRA] interface vlanif 100
[LSRA-Vlanif100] ip address 172.1.1.1 255.255.255.0
[LSRA-Vlanif100] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 100
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface gigabitethernet 0/0/2
[LSRA-GigabitEthernet0/0/2] port link-type trunk
[LSRA-GigabitEthernet0/0/2] port trunk allow-pass vlan 100
[LSRA-GigabitEthernet0/0/2] quit
[LSRA] interface loopback 1
[LSRA-LoopBack1] ip address 1.1.1.9 255.255.255.255
[LSRA-LoopBack1] quit
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
After the configurations are complete, run the display ip routing-table command
on each LSR. You can see that the LSRs have learned the routes to Loopback1
interfaces of each other.
Step 2 Configure basic MPLS functions and enable MPLS TE, RSVP-TE, and CSPF.
# Configure LSRA. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here. CSPF only needs to be
configured on the ingress node of the primary tunnel.
[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] mpls te
[LSRA-mpls] mpls rsvp-te
[LSRA-mpls] mpls te cspf
[LSRA-mpls] quit
[LSRA] interface vlanif 100
[LSRA-Vlanif100] mpls
[LSRA-Vlanif100] mpls te
[LSRA-Vlanif100] mpls rsvp-te
[LSRA-Vlanif100] quit
Step 3 Configure OSPF TE.
# Configure LSRA. The configurations of LSRB and LSRC are similar to the
configuration of LSRA, and are not mentioned here.
[LSRA] ospf
[LSRA-ospf-1] opaque-capability enable
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] mpls-te enable
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit
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Step 4 Create an MPLS TE tunnel on the ingress node.
# Create Tunnel1 on LSRA.
[LSRA] interface tunnel 1
[LSRA-Tunnel1] ip address unnumbered interface loopback 1
[LSRA-Tunnel1] tunnel-protocol mpls te
[LSRA-Tunnel1] destination 3.3.3.9
[LSRA-Tunnel1] mpls te tunnel-id 101
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit
After the configurations are complete, run the display interface tunnel command
on LSRA. You can see that the tunnel interface status is Up.
[LSRA] display interface tunnel 1
Tunnel1 current state : UP
Line protocol current state : UP
Last line protocol up time : 2013-02-22 14:28:37
Description:...
Step 5 On LSRA and LSRB, configure RSVP authentication on the interfaces on the MPLS
TE link.
# Configure LSRA.
[LSRA] interface vlanif 100
[LSRA-Vlanif100] mpls rsvp-te authentication cipher Huawei@1234
[LSRA-Vlanif100] mpls rsvp-te authentication handshake
[LSRA-Vlanif100] mpls rsvp-te authentication window-size 32
[LSRA-Vlanif100] quit
# Configure LSRB.
[LSRB] interface vlanif 100
[LSRB-Vlanif100] mpls rsvp-te authentication cipher Huawei@1234
[LSRB-Vlanif100] mpls rsvp-te authentication handshake
[LSRB-Vlanif100] mpls rsvp-te authentication window-size 32
[LSRB-Vlanif100] quit
Step 6 Verify the configuration.
Run the reset mpls rsvp-te command, and then run the display interface tunnel
command on LSRA. You can see that the tunnel interface is Up.
Run the display mpls rsvp-te interface command on LSRA or LSRB to view
information about RSVP authentication.
[LSRA] display mpls rsvp-t