Optical World D1 - 25/04/01 Present document contains informations proprietary to France Telecom. Accepting this document means for its recipient he or

Optical World D1 - 25/04/01

Present document contains informations proprietary to France Telecom. Accepting this document means for its recipient he or she recognizes the confidential nature of its content and his or her engagement not to reproduce it, not to transmit it to a third party, not to reveal its content and not to use it for commercial purposes without previous FTR&D written consent.

Network architecturetools to support network operatorrequirements

Luc Le Beller FTR&D/DAC

France Telecom R&D Diffusion of this document is subject to France Telecom authorizationOptical World D2 - 25/04/01

Outline

Introduction and scope

Generic transport layer structure

Two examples of IP over optical network configurations

Additional architectural components

Service description

Conclusion


Technical background

Transport network architecture is driven by the following items :

An important diversity of transport network techniques inthe core and the access : SDH, ATM, IP, MPLS, OTN, GbE

The development of control(s) plane(s) in addition tomanagement(s) plane(s) : from B-ISDN to ASON

A lot of different architectural models coming from thestandardisation : ITU-T, IETF, OIF


Operator backgroundTransport network architecture is driven by the following items :

Diversification from raw transport service

Provisioning/reconfiguration time enables differentiation from competition

Transport carriers must differentiate their services and climb on the value chain

Bandwidth on demand (wavelengths, SDH VCs) : OSP (optical service provider) i.e. Storm

Modulation of quality of service (protection levels)

VPN

Dynamicity

Transport costs decreased

Monopoly era with reliable voice and LL services demand forecasts is over

Emergence of multiple new services with uncertain needs

Impact of competitors market share and network architecture options


Scope

Full description of the transport network components

General interaction between transport network components

Interaction between transport network components and othernetworks and services components

Consistent top-down (from the service to the network) andbottom-up (from the network to the service) description

G.805 and derived standards, G.8080 and derived standards : very low granularity

Depending on organisation structure (actors, business units)

Also depending on organisation structure with more actors and business units

SG 15 bottom-up approach ; SG 13 top-down approach


Outline





Service description

Conclusion


Generic Layer Structure

A generic layer structure for transport network, independent of the techniques, is obtainedby combination of the following criteria :- Does the layer provide flexible connectivity (G.805 sub-network capability) or not ?- What type of resources in the layer needs to be reserved in response to a client request for the transport of his (characteristic) information ?

FW

SW/XC

PHYLayer(s) offering point-to-point connectivityis named PHY layer

Layer(s) offering flexible connectivity and requiring specific resources allocation forEvery sub-network is named SW/XC

Layer(s) offering flexible connectivity and not requiring specific resources allocationfor every sub-network is named FW


Transport Network Techniques

FW

SW/XC

PHY

MPLS, ATM VP/VC,SDH VC-X, ETH MAC,OTN ODUk/OCh

IP

SDH RS/MS, OTN OTS/OMSETH PHY, Optical Fiber

Not only physical !!

It is assumed that a G.805 client/server relationship is existing between all these layers


One example

IP

SW/XC

STM-N/WDMPHY

FW

ATM VP/VC

SDH VC-4/VC-4-4c

IP

ATM VP

VC-4-4c

STM-4 STM-4

ab

c

de

Equivalent G.805 representation of a, e, k and c client/server relationships

a a

e e

k kc c

e e

k k

k VC-4-4c


Outline





Service description

Conclusion


IP over optical configurations

O2

O1

Optical Network

O3

I6I4R6

R5

R4

IP Network

IP Network

IP Network

I5

Can both IP adjacencies R4-R6 and R4-R5coexist on the same I4 interface ?


Concatenated versus channelised

IP FW

OTN

IP

OF

OTN OTN

CHANNELISED : more than oneadjacency per interface

IP

SW/XC

STM-16/OFPHY

FW

OTN

IP

OFPHY

CONCATENATED : only oneadjacency per interface

SW/XC

The SW/CX layer issupporting the PHY layer !

PHY


Outline





Service description

Conclusion


General processesFor the description of the services telecommunication, it is useful to structureall the actions required to offer a service in the following (and chronologically) way :

- pre-sales (PSA)-subscription (SCR)- invocation (INV)- assurance (ASU)- billing (BIL)

This structure can also be applied to the transport network and as example to the IP over optical configurations where the service is : creation of anIP adjacency between routeur R4 and R5

O2

O1

Optical Network

O3R6

R5

R4IP Network

IP Network

IP NetworkI4I6

I5


Operations for conc. and chan. (1)

CHANNELISEDCONCATENATED

PSA SCR INV

-Routerslocalisation

-Routersdeployment

-InterfacesI4 and I5installation

-Createopticalchannel

PSA SCR INV


-Routersdeployment

-Createopticalchannel(s)

1

2

31

2

3 4

Step 4 requires a step 3 :the same dynamics applies

Step 4 can be independent of step 3 :different dynamics can apply

Operations 1 to 4 are required to create an adjacency between routers R4and R5

-InterfacesI4 and I5installation

4


Operations for conc. and chan. (2)

Optimized procedure for the CONCATENATED configuration

PSA SCR INV


-Routersdeployment

-Createopticalschannels

1

2

4

This requires the provisioning ofrouters with the maximum capacityof interfaces

3 -Interfaces Ixinstallation

Optimized procedure for theCHANNELISED configuration

PSA SCR INV


-Routersdeployment

-Createopticalschannels

1

2

3 4

This requires installation ofinterfaces at the highest capacity

-InterfacesI4 and I5installationat maximumbit-rate

! : optimisation is considered from the IP network side


Transport service definition at G.805 level

1) Trail serviceLayer Y

Layer X

LIK Y1

TRAIL X

Layer X

SNC XA

B

2) Sub-networkconnection service

Note : trail service requires at least one sub-network connection service (except if X is a PHY layer)

A and B : access groupsor sub-networks

Telecommunication service modelling requires other considerations : additional transport layers, division in actors (partitioning),control plane components, …


Conclusion

It has been shown on a basic IP over optical configuration that a technicalchoice has great impact on the global architecture.

This was made possible by a network modelisation at a low-level ofgranularity, which assembles well defined elementary architectural components.

Elementary architectural components must continue to be standardised independently of the technology

There is no need to standardize more global architectural tools

Documents

Optical World D1 - 25/04/01 Present document contains informations proprietary to France Telecom. Accepting this document means for its recipient he or