International Telecommunication Union
ITU-T
Identification and Specification of
NGN Service and Control
Requirements
Tobey Trygar
Telcordia Technologies
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
Overview
ITU-T
o Performance of Services and
Networks
o Physical Views of Networks
o Service Information Flows
o OSI and G.805 Layers
o Interesting Time Scales
o Issues and Questions
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
2
Service Performance verses Network Performance
ITU-T
o A Service Provider focuses on Service Resources
o A Service Customer focuses on Service Performance
Support
Performance
Operability
Performance
Accessibility
Performance
Retainability
Performance
Integrity
Performance
Security
Performance
Component Of
Service
Performance
Is The Basis For
Network
Performance
Component Of
Planning, Provisioning,
and Administration
Performance
Trafficability
(Grade of Service)
Performance
Network Item
Dependability
Performance
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
Transmission
Performance
3
Views of Quality of Service
ITU-T
o QoS is the degree of conformance of the
service delivered to a user by a provider in
accordance with an agreement, e.g., an SLA
Quality of Service
(QoS)
Type Of
Traffic Engineering
QoS Specifications
QoS Desired By
Customers
QoS Perceived
QoS Delivered
QoS Offered By
Service Provider
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
4
Physical Network Topology
ITU-T
Core Network
VIP
HUB
CO
HUB
CO
VIP
HUB
CO
Metro Network
ISP
HUB
CO
ISP
CO
Inter-Office Facilities
Collector
Ring
CO = Central Office
DLC = Digital Loop Carrier
DSLAM = DSL Access Multiplexer
ISP = Internet Service Provider
ONU = Optical Network Unit
CO
CO
Access
Business
Access
Ring
O
N
U
DLC
DLC
xDSL
ADM
DSLAM
POS
ONT = Optical Network Termination
POS = Passive Optical Splitter
PON = Passive Optical Network
VIP = Video Information Provider
IP, GbE
LAN
xDSL
PON
ONT ••• ONT
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
5
Domains of Applicability
ITU-T
Metro
Access
Layer 3
Layer 2
Edge/Aggregation
Routers
Core
Core Routers
MPLS/ATM/FR
Core Switches
GbE/ATM/MPLS
Access Switches
MSPP/RPR
Physical
Grooming
OXC
Core
OXC
Core OADM
Metro/Regional
OADM
Residential Enterprise
Access
Access
Metro WDM
Aggregation/Distribution
Networks
Long Haul
DWDM
ULH
DWDM
Regional
Networks
MSPP = Multi-service Provisioning Platform
OADM = Optical Add-drop Multiplexer
OXC = Optical Cross-connect
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
RPR = Resilient Packet Ring
ULH = Ultra-long Haul
6
Typical IP (and beyond) Encapsulations
ITU-T
IP
IEEE 802.2 LLC
IEEE 802.2 LLC
RPR MAC
RPR PHY
PPP
Ethernet MAC
10GbE
LAN PHY
10GbE
WAN PHY
HDLC
AAL5
ATM
GbE
PHY
GFP
SONET / SDH
G.709 OCh digital wrapper/ optical channel
Optical fibre / G.652, G.653 etc.
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
7
Service Related Information Flows
ITU-T
OAM Delivery
Network
Signalling-Control
Delivery Network
Service Delivery
Network
Service
Node 1
Service
Node k
Customer
Node 1
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
Customer
Node i
8
Multi-Administrative Domain Services
ITU-T
End-to-End Service
...
Administrative
Domain 1
...
Administrative
Domain 2
...
Administrative
Domain 3
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
...
Administrative
Domain 4
...
9
Connection Set-Up in Layer 1
ITU-T
Signaling for given path layer is understood
Connection
Matrix
..
.
Connection
Matrix
..
.
Connection
Matrix
Path Layer
Abstract Signaling Interface
Server Layer to Path Layer
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
10
Physical View Of A Linear OTN
ITU-T
OTN Client Signal
OTN Client Signal
ODU
ODU
Termination
ODU
Termination
OCh/OTU
OCh/OTU
OCh/OTU
Termination
OCh/OTU
Termination
OMS
OMS
Termination
OTS
Termination
Physical
Layer
ONE
OTS
OTS
Termination
OMS
Termination
OTS
OTS
Termination
OMS
OTS
OCh/OTU
Termination
OMS
OMS
Termination
OTS
Termination
OTS
OTS
Termination
OMS
Termination
OTS
OTS
Termination
Physical
Layer
Physical
Layer
Physical
Layer
Physical
Layer
Physical
Layer
ONE
ONE
ONE
ONE
ONE
ONE = Optical Network Element
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
11
IP/OTN Performance
ITU-T
o Both technologies support unique performance
o
o
o
o
mechanisms with IP predominately uni-directional
and OTN bi-directional.
Depending on the OTN survivability mechanisms,
the IP layer may assume OTN performance to be
predictable.
Survivability speeds within the OTN may interact
with IP routing convergence.
IP routers as ASON clients, may change OTN
performance characteristics, e.g., error rates,
bandwidth, and link creation.
End-to-end IP client performance will require
consideration of both the IP layer and the OTN
layers.
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
12
Signaling within and between Layers
ITU-T
Layer 3
Routing / Forwarding
Abstract Signaling Interface
Layer 2
Contains Connection Oriented and Connectionless Protocols
Abstract Signaling Interface
Path Layer Signaling
Layer 1
Client - Server Signaling
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
13
Time Scales for Typical Events
ITU-T
Automatic
Service
Restoration
Automatic
Protection
Switching
Network
Resource
Optimization
Service
Customer
AdditionRemoval
Tens of
Milliseconds
Capacity Addition
Following Major
Disruption
Tens of
Hours
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
14
Issues and Questions
ITU-T
o Traditional performance allocation is horizontal, i.e. hypothetical
o
o
o
o
o
reference networks. Is a vertical allocation needed?
Is there a calculus for aggregating performance metrics across
layers
If a capability can be supported at multiple layers, how should
these capabilities be coordinated?
Some layer characteristics change with time due to technology
advances. Is there a need for a family of layer characterization
templates?
Are there a set of principles for allocating performance functions
to layers based on characteristics?
Clients can use numerous server layers. Is there a generic interlayer signalling model needed?
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
15
Back-Up Slides
ITU-T
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
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The Optical Transport Network
ITU-T
o
The Optical Transport Network (OTN)
• Is specified primarily in G.872, G.709, G.798, G.959.1, and G.874,
• Is currently limited to the transport of digital signals
• Provides transport, multiplexing, routing, supervision and survivability
of client signals
o
It is composed of the following digital layers:
• Optical Channel Data Unit (ODU), Path and Tandem Connection
• Optical Channel Transport Unit (OTU)
o
It is composed of the following photonic layers:
•
•
•
•
Optical Channel (OCh) Layer, OCh Reduced (OChr)
Optical Multiplex Section (OMS) Layer
Optical Transmission Section (OTS) Layer
Optical Physical Section (OPS) Layer
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
17
OTN Survivability Mechanisms
ITU-T
o The two fundamental survivability mechanisms supported in
the OTN are protection and restoration schemes.
o Protection schemes are:
• Autonomous and make use of pre-established backup resources
• Optical Multiplex Section (OMS) resilience - all channels in a fiber
(or fiber bundle) protected as a whole,
• Optical Channel (OCh) resilience - each optical channel is
protected individually.
o Restoration schemes are:
• Reactive and make use of dynamically identified backup,
• Management system or signalling system based,
• Require network state information.
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
18
References
ITU-T
o E.106, Description of an International Emergency
Preference Scheme (IEPS)
o E.490.1, Overview Of Recommendations On Traffic
o
o
o
o
Engineering
E.800, Terms And Definitions Related To Quality Of Service
And Network Performance Including Dependability
E.801, Framework For Service Quality Agreement
E.860, Framework For A Service Level Agreement
G.709, Network Node Interface For The Optical
Transport Network (OTN)
o G.798, Characteristics of Optical Transport Network
Hierarchy Equipment Functional Blocks
o G.805, Generic Functional Architecture Of Transport
Networks
o G.806, Characteristics of Transport Equipment -
Description Methodology and Generic Functionality
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
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References
ITU-T
o G.872, Architecture Of Optical Transport Networks
o G.874, Management Aspects Of Optical Transport
Network Elements
o G.959.1, Optical Transport Network Physical Layer
Interfaces
o G.7041,
Generic Framing Procedure
o G.7710, Common Equipment Management Function
Requirements
o G.7712, Architecture And Specification Of Data
Communication Network
o G.7713, Distributed Call and Connection Management
o G.7713.1, Distributed Call and Connection Management
(DCM) Based on PNNI
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
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ITU-T
o
G.7713.2, DCM Signalling Mechanism Using GMPLS RSVP-TE
o
G.7713.3, Distributed Call and Connection Management Signalling
Using GMPLS CR-LDP
o
G.8080, Architecture for the Automatic Switched Optical Network
(ASON)
o
GB 917, SLA Management Handbook Series Version 2, TeleManagement
Forum
o
M.20, Maintenance Philosophy for Telecommunications Networks
o
M.3010, Principles For A Telecommunications Management Network
o
X.700, Management Framework for Open Systems Interconnection
(OSI) for CCITT Applications
o
Y.1271, Framework(s) on Network Requirements and Capabilities to
Support Emergency Communications Over Evolving Circuit Switched
and Packet Switched Networks
ITU-T Workshop “NGN and its Transport Networks“
Kobe, 20-21 April 2006
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