[PPT] - Routing in Multi- -Layer Layer Routing in Multi Transport PowerPoint Presentation

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I nternational Telecom m unication Union

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Routing in Multi Routing in Multi-

Layer

Layer Transport Networks Transport Networks

Jonathan S adler

Office of the CTO – Technology S trategy, Tellabs Chair, OIF Architecture & S ignaling Working Group S G15 S pecial Representative to IETF for Routing

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Agenda

S

ervice-based routing

AS

ON Multi-layer Routing Architecture

Remote Path Computation

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Discussion of Convergence is Everyw here

“ …

the access infrastructure telcos are building to support IPTV services will finally give them the ability to converge voice, video and data onto a single network… ” – Americas Network

Pseudo-Wires are “ the solution for convergence in future

telecom networks, because it preserves profitable legacy services even as it enables the creation of a truly next- generation network” – Heavy Reading

“ 3GPP defines a new subsystem to enable the convergence of

voice and data applications and the harmonization of various mobile network technologies over IP” – Deutsche Bank

Convergence is changing the face of the network

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The Benefits of Convergence

S

ervices reduced to applications on converged infrastructure

Reduced operations
Reduced core cap-ex
New services can be provided
Individual Networks per S

ervice limited service interaction

Packet & optical routing convergence can improve network

performance even if only IP services are provided

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The Reality of Convergence

Non-native service delivery
End User S

ervices are always layered on something else

The whole network will not be converged overnight
Too many existing services already deployed
The whole network will never be completely converged
Fully depreciated equipment still generates revenue

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How Can This Be Accom m odated?

Common flexible control method that understands layering
Path Computation that understand layered net works

—Provides service routing given view of potential/ available server layer resources

S

ignaling mechanisms that coordinate calls in different layers

OSS

es that can handle integrated views of layer networks —Relate services requests (client layer calls) to server resources in use

Definitions for server layer resources other than SONET/ S

DH

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Access A Access B Core CPE-A CPE-B

The Network is Segmented

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CPE-A CPE-B

Different Organizations Manage Different Parts of the Network

Access A Access B Core

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CPE-A CPE-B

Provisioning Service is expensive and time consuming

We will fill your order within 3 months I forgot that we ordered this service!

Access A Access B Core

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CPE-A CPE-B

Control Plane Speeds it up

Access A Access B Core

Sure, we’re setting your service up as we speak Wow, that was fast!

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CPE-A CPE-B

Will use of different technologies cause the problem to reoccur?

Access A (Ethernet) Access B (SONET/SDH) Core (MPLS Pseudo Wire)

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Ethernet Network

GE/NNI BPON OCN/NNI GE/NNI GE/UNI T1, T3, OCN UNI GE/NNI 10/100 BPON 10/100 T1, T3, OCN UNI GE/NNI

STS1 Network*

OCN/NNI OCN/NNI nxT1 OCN/NNI OCN/NNI GE/UNI T1, T3, OCN UNI or Null OCN/NNI 10/100 nxT1 GE/MPLS 10/100 T1, T3, OCN UNI or Null OCN/NNI

MPLS Network*

OCN UNI OCN UNI BPON

CPE-B Access A (Ethernet) Access B (SONET/SDH) Core (MPLS Pseudo Wire)

It doesn’t have to…

CPE-A

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Ethernet Network

GE/NNI BPON OCN/NNI GE/NNI GE/UNI T1, T3, OCN UNI GE/NNI 10/100 BPON 10/100 T1, T3, OCN UNI GE/NNI

STS1 Network*

OCN/NNI OCN/NNI nxT1 OCN/NNI OCN/NNI GE/UNI T1, T3, OCN UNI or Null OCN/NNI 10/100 nxT1 GE/MPLS 10/100 T1, T3, OCN UNI or Null OCN/NNI

End-to-end Signaled Service Provisioning!

Sure, we’re setting your service up as we speak Wow, that was fast! MPLS Network*

OCN UNI OCN UNI BPON

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I nternational Telecom m unication Union

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ASON Multi ASON Multi-

layer Routing

layer Routing Architecture Architecture

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Multi-layer overview

Need path computation for a network made up of many

different technologies, in any layer that has switching flexibility.

Current methods separate network topologies per

technology, creating separate discontinuous graphs

Path Computation methods only operate on graphs without

discontinuity.

Need to make a continuous routing view for a multi-technology network

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Representation of Server Layer connectivity

G.8080 (2006): Two maj or approaches, with two minor forms:
S

erver Layer Representation using Links only:

—Client layer links resulting from established server layer trails

Result of cross connection of fibers, HOVC paths, etc.

—Client layer links provided by potential server layer trails

Abstract links representing potential connectivity
Requires management specification
S

erver Layer Representation using Links & S ubnetworks

—Client layer abstract node containing server layer

Abstract topology representing potential connectivity
Can be generated automatically

—S erver layer topology shadow in client layer

Non-abstract topology showing server links incl. attributes
Can be generated automatically

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Connection is established in S

erver Layer

Link appears in Client Layer

Representation using client links ( actual)

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Link is put into client layer knowing that server layer

resources exist

S

erver layer trail is established when link is put into use

Representation using client links ( potential)

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Client layer is provided with an abstract node that represents

the server layer connectivity

Routing can compute a path in the client layer
S

erver layer connection established when abstract node appears in client layer ERO

Representation using client subnetw ork

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Client layer contains server layer topology
Routing can see all attributes of server layer resources
S

erver layer connection established using client layer ERO information

Representation using client subnet & links

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W hat inform ation is required?

Understanding of adaptations in use
Understanding of termination/ switching capability
Ability to control choice of server layer trails in

place of client layer links

G.805 Policy

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W hat inform ation is required?

GMPLS

Routing Announcements

Limited to switching capability information
Need to add adaptation and termination capability info
Adding this information creates a “ backward

compatibility” problem

S

imilar to problem that exists between MPLS and GMPLS

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I nternational Telecom m unication Union

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ASON Support for ASON Support for Remote Path Computation Remote Path Computation

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W hat is PCE?

PCE = Path Computation Element
Facilitated by AS

ON Functional Architecture

Functional Architecture makes no assumptions on

physical location

Essentially a remote procedure call method
Used within an area between S

ignaling (CC) and Routing instances (RC)

Used between areas by routing instances (RC)

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Enables end-to-end path computation without knowing the

whole network topology

S
urce specified constraints are communicated
Path Computation performed on nodes with access to

topology

Provides support for inspecting interior of abstract nodes

W hat is PCE? Use of PCE in single technology areas

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Exam ple of PCE interaction

LRM CC RCA1

A

RCA0

D

LRM CC RCA0

H

LRM CC RCA1

B

LRM CC RCA1 LRM CC RCA3

F

LRM CC RCA3

G

LRM CC RCA3

I

Connection Request 1 2 3 6 4 5 7 8 9 12 15 18 21 24 27 29 30 11 10 13 14 17 16 22 23 25 26 28 31 32 33 34 35 36 RCA0

C

LRM CC LRM CC RCA2

E

20 19 RCA2 RCA3

Equipment Node Subnetwork Routing Area

A B C E G F I

RC-RC Route Query L1 L2 L3 L4 L5 L6

D H G

A1 A2 A3 A0

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If all nodes to support multi-layer control plane, need for

PCE is limited to path computation for special constraints

Many network requests can be handled through ASON S
urce

Routing methods

Nodes that don’ t support multi-layer control plane can PCE

to make up for inability to support new routing attributes

Use of PCE in m ixed-technology areas

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Exam ple of m ulti-technology PCE interaction

LRM CC RCA1

A

RCA0

D

LRM CC RCA0

H

LRM CC RCA1

B

LRM CC RCA1 LRM CC RCA3

F

LRM CC RCA3

G

LRM CC RCA3

I

Connection Request 1 2 3 6 4 5 7 8 9 12 15 18 21 24 27 29 30 11 10 13 14 17 16 22 23 25 26 28 31 32 33 34 35 36 RCA0

C

LRM CC LRM CC RCA2

E

20 19 RCA2 RCA3

Equipment Node Subnetwork Routing Area

A B C E G F I

RC-RC Route Query L1 L2 L3 L4 L5 L6

D H G

A1 A2 A3 A0

WDM SDH SDH

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Conclusion

Network continues to strive for convergence
Convergence technology chosen will be based on services
ffered, causing different technologies to be used
Network will not be converged overnight
New mechanisms defined in G.8080 to represent

multi-layer networks allowing for path computation.

Path Computation Elements provide a method for