Locator/ID Separation Protocol (LISP)
Architecture & Protocols
LISP Team:
Vince Fuller, Darrel Lewis, Eliot Lear, Scott Brim,
Dave Oran, Elizabeth McGee, Dino Farinacci, and David Meyer
Workshop III: Beyond Internet MRA: Networks of Networks
Institute for Pure and Applied Mathematics
Nov 3-7, 2008
Agenda
•
•
•
•
•
•
•
Problem Statement
Locator/ID Separation (and why…)
What is LISP?
LISP Control Plane - LISP+ALT
How LISP sites talk to legacy sites
Other Uses of LISP
Prototype and Pilot Network
LISP Arch & Protocols
IPAM MRAWS3
Slide 2
Problem Statement
Provider A
10.0.0.0/8
Provider B
11.0.0.0/8
R1
Lower OpEx for Sites and Providers
(1) Improve site multi-homing
(2) Improve site & provider traffic
engineering
(3) Reduce size of core routing tables
(4) IPv4 Address Conservation?
R2
BGP
Site with
PI Addresses
LISP Arch & Protocols
End Site Benefit
(1)
(2)
(3)
(4)
Easier Transition to IPv6
Change provider without address change
Active-Active BGP-free Multihoming
Data Center Load Spreading
IPAM MRAWS3
Slide 3
Scaling Internet Routing State
LISP Arch & Protocols
IPAM MRAWS3
Slide 4
Why Separate Location from ID?
• Level of Indirection allows us to:
– Keep either ID or Location fixed while changing the
other
• Basically: Routing Locators need to aggregate
topologically, while IDs are usually assigned along
administrative boundaries  hard to do with one number
space
– Create separate namespaces which can have
different allocation properties
• By keeping IDs fixed
– Assign fixed addresses that never change to hosts
and routers at a site
• You can change Locators
– Now the sites can change providers
– Now the hosts can move
LISP Arch & Protocols
IPAM MRAWS3
Slide 5
Separating (or adding) an Address
Changing the semantics of the IP address
ID & Location
IPv6:
2001:0102:0304:0506:1111:2222:3333:4444
Locator
ID
ID & Location
IPv4:
209.131.36.158 .10.0.0.1
Locator
LISP Arch & Protocols
IPAM MRAWS3
If PI, get new locator
If PA, get new ID
ID
Slide 6
Multi-Level Addressing
Provider A
10.0.0.0/8
Provider B
11.0.0.0/8
R1
R2
EIDs are inside of sites
S
LISP Arch & Protocols
RLOCs used in the core
IPAM MRAWS3
Slide 7
Map-n-Encap vs Address-Rewrite
Map-n-Encap
Address-Rewrite
Host Stack:
supplies IDs
Host Stack:
supplies IDs
Router:
rewrites RLOCs
from existing
address
Router:
supplies RLOCs
by adding new
header
GSE
LISP
LISP Arch & Protocols
IPAM MRAWS3
Slide 8
So What is LISP?
LISP Arch & Protocols
IPAM MRAWS3
Slide 9
What is LISP?
• Locator/ID Separation Protocol
–
–
–
–
–
–
Network-based solution
No changes to hosts whatsoever
No new addressing changes to site devices
Very few configuration file changes
Imperative to be incrementally deployable
Address family agnostic
LISP Arch & Protocols
IPAM MRAWS3
Slide 10
New Network Elements
• Ingress Tunnel Router (ITR)
– Finds EID to RLOC mapping
• This is the map part of map-and-encap
– Encapsulates to Locators at source site
• This is the encap part of map-and-encap
• Egress Tunnel Router (ETR)
– Authoritative for its EID to RLOC mapping
– Decapsulates at destination site
LISP Arch & Protocols
IPAM MRAWS3
Slide 11
Packet Forwarding
PI EID-prefix 1.0.0.0/8
ITR
Provider A
10.0.0.0/8
S1
S
PI EID-prefix 2.0.0.0/8
ETR
Provider X
12.0.0.0/8
D1
ITR
S2
Provider B
11.0.0.0/8
D2
Provider Y
13.0.0.0/8
1.0.0.1 -> 2.0.0.2
1.0.0.1 -> 2.0.0.2
11.0.0.1 -> 12.0.0.2
DNS entry:
D.abc.com
D
ETR
11.0.0.1 -> 12.0.0.2
1.0.0.1 -> 2.0.0.2
A 2.0.0.2
EID-prefix: 2.0.0.0/8
Mapping
Legend:
EIDs -> Green
Locators -> Red
LISP Arch & Protocols
1.0.0.1 -> 2.0.0.2
Entry
Locator-set:
12.0.0.2, priority: 1, weight: 50 (D1)
13.0.0.2, priority: 1, weight: 50 (D2)
IPAM MRAWS3
Policy controlled
by destination site
Slide 12
Mapping Database Designs
• You need a “map” before you can “encap”
• We have designed several mapping database
protocols
– CONS, NERD, EMACS, ALT
– Tradeoff push versus pull benefit/cost
– Needs to be scalable to 1010 entries
• ALT has the most promise
– We are deploying ALT
LISP Arch & Protocols
IPAM MRAWS3
Slide 13
What is LISP+ALT?
• EID namespace is used at the site
• RLOC namespace is used in the Internet core
• Mappings need to be authoritative and reside
at site ETRs
• Advertise EID-prefixes in BGP on an
alternate topology of GRE tunnels
• ITRs get mappings by routing Map-Requests
on ALT topology
• ETRs respond with Map-Replies
LISP Arch & Protocols
IPAM MRAWS3
Slide 14
How LISP+ALT Works
EID-prefix
240.0.0.0/24
11.0.0.1 -> 240.1.1.1
11.0.0.1 -> 240.1.1.1
?
240.0.0.1 -> 240.1.1.1
ITR
Legend:
240.0.0.1 -> 240.1.1.1
240.0.0.1 -> 240.1.1.1
ITR
?
?
< - 240.1.0.0/16
ALT-rtr
ALT-rtr
ETR
EID-prefix
240.1.1.0/24
ETR
EID-prefix
240.1.2.0/24
ALT-rtr
ALT-rtr
ALT-rtr
EIDs -> Green
240.0.0.1 -> 240.1.1.1
ALT-rtr
Locators -> Red
GRE Tunnel
ALT
Low Opex
Physical link
Data Packet
Map-Request
ETR
EID-prefix
240.2.1.0/24
11.0.0.1 -> 1.1.1.1
?
Map-Reply
LISP Arch & Protocols
240.0.0.1 -> 240.1.1.1
IPAM MRAWS3
1.1.1.1 -> 11.0.0.1
Slide 15
Interworking Model
• We’ve built and deployed the interworking mechanisms
described in draft-lewis-lisp-interworking-01.txt
• LISP Translation
– “LISP NAT”
– http://www.translate.lisp4.net
• Proxy Tunnel Router (PTR)
– Advertises coarsely aggregated EID-prefix(es) into the DFZ
• Attracts traffic for those prefixes
– Behaves like an ITR for that traffic
•
•
•
•
tr0.partan.com is a v4 PTR
titanium-dmm-alt-only.lisp.uoregon.edu is a v6 PTR
http://www.lisp6.net uses the v6 PTR
http://www.lisp4.net uses the v4 PTR
LISP Arch & Protocols
IPAM MRAWS3
Slide 16
Other Uses for LISP
• SLBs in Data Centers
– ETRs directly connected to servers
– ITRs at Data Center edge
• A/V Mobile Truck Roll
– Avoid renumber at each event
• BGP-free Core
– Intra-AS avoiding storing external routes
– RLOCs are PE routers
• Building topological hierarchy with flat addressing
– MAC addressing in L2 networks
• MAC address mobility for “extended subnets”
• In an environment of shortage address supply
LISP Arch & Protocols
IPAM MRAWS3
Slide 17
Prototype and Pilot
• Prototype has been running for a 1.5 years
– NX-OS on Titaniums
– IOS is under-way
– Considering XR and/or CRS blade implementation
• Alpha has been running for 1 year
– Map-Request/Reply, ALT, & Interworking
• External pilot is underway
–
–
–
–
–
–
Dual-stack ALT
Underlying IPv4 and IPv6 transport
Geographical (registry-based) EID addressing
Interworking IPv4 with translation and PTRs
Interworking IPv6 with PTRs
Low-OpEx xTRs underway
LISP Arch & Protocols
IPAM MRAWS3
Slide 18
LISP Arch & Protocols
IPAM MRAWS3
Slide 19
LISP in one Slide
“Separating ID and Location from an IP address through a level of indirection”
LISP-ALT Control Plane
LISP Site
EIDs
LISP
Routers
LISP Site
Advertises EID-prefixes
to find mappings
LISP
Routers
CE
CE
RLOCs
RLOCs
Today’s Internet - Data Plane
Configure EID -> RLOCs
database mappings
for local site
Data Packet
EIDs assigned by
Internet Registries
RLOCs assigned by
Service Providers
RLOCs
EIDs
Payload
OH
IH
Host Data
Advertises RLOCs to maintain aggregation
and provide reachability to sites
Improved low-opex multihoming
Site based policy and reachability
No changes to core routers
No changes to site routers
No DNS changes
No site addressing changes
Works with PI or PA prefixes
Supports 44-over-6 and 66-over-4
Sites authoritative for their mappings
Interworks with non-LISP sites using
translation or PTRs
Tue Nov 4 18:33:30 PST 2008
Stores EID -> RLOCs
cache mappings
for remote sites
Costs:
Benefits:
•
•
•
•
•
•
•
•
•
•
EIDs
RLOCs
CE
RLOCs
Non-LISP Site
• Mapping system required
• New Software in CE routers
• New LISP-ALT infrastructure
Legend:
EIDs (End Site IDs) in green
RLOCs (Routing Locators) in red
CE: Customer Premise Edge Router
ALT: Alternative LISP Topology
OH: Outer header, CE to CE
IH: Inner header, host to host
LISP Internet Drafts
draft-farinacci-lisp-09.txt
draft-fuller-lisp-alt-03.txt
draft-lewis-lisp-interworking-01.txt
draft-farinacci-lisp-multicast-00.txt
draft-meyer-lisp-eid-block-01.txt
draft-mathy-lisp-dht-00.txt
draft-iannone-openlisp-implementation-01.txt
draft-brim-lisp-analysis-00.txt
draft-meyer-lisp-cons-04.txt
draft-lear-lisp-nerd-04.txt
draft-curran-lisp-emacs-00.txt
LISP Arch & Protocols
IPAM MRAWS3
Slide 21
References
• Public mailing list:
lisp-interest@lists.civil-tongue.net
• Go to a LISP site now:
http://www.lisp4.net
http://www.lisp6.net
LISP Arch & Protocols
IPAM MRAWS3
Slide 22