MPLS Multiple Topology Support

draft-zhao-mpls-ldp-multiple-topology-01 draft-zhao-mpls-rsvp-te-multiple-topology-01

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Quick Review for These Two Drafts

In the previous version of the drafts, we have

discussed a few application scenarios;

The basic ldp and rsvp-te protocol extensions to

support mpls multiple topology;

The forwarding options to support mpls multiple

topologies;

When we presented these two drafts in IETF77, one

of the comments we got is to work with service providers

to pin down the exact application scenarios where mpls

multiple topology can provide unique solutions;

The extended FEC TLV has the format as below:

Review: Extensions to LDP

FEC Element 1

MT-IDreserved

FU FEC(TBD)

FEC Element n

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Review: Extensions to RSVP-TE

Add MT Information into an object in a message

Add MT Information into SESSION object

Extended P2P SESSION object for IPv4

IPv4 Tunnel End Address

Extended Tunnel ID

Tunnel IDMT-ID (12 bits)Resv

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Review: MPLS Forwarding in MT

Option 1: MT is implied by Label

On a LSR, same FEC with different MT-ID mapped to different

Label

Advantages: No hardware changes

Disadvantages: Label space is limited

Option 2: MT is indicated by stacked Label

One extra label is stacked to indicate a topology

Advantages: Each topology has a full label space

Disadvantages: Forwarding is complicated

What is Done in this Version of the Drafts?

The prototyping is done and has been demonstrated for a few service providers;

There are a few scenarios added in these drafts: Protection Solution using MPLS Multiple Topology； Simplify the inter-AS VPN solutions;

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Application Scenario Example 1: End-to-End mLDP P2MP backup LSP

The primary P2MP LSP set up in the red topology is backed up by the secondary P2MP LSP setup in the blue topology, where the red topology and blue topology don’t share the common links and nodes if it is required.

Application Scenario Example2

backbone

MAN MAN

AS x

MAN MAN

AS y

Province Network

AS9808

O&M serverBackbone router

Province router

In order to deploy MPLS VPN with entire network, there is a strong demand to support inter-AS connection and E2E O&M

AS O&Mbackbone network

Public AS: 9808

headquarter

province network

Private AS: x

province

Headquarter O&M

Province O&M

Solution for Inter-AS MPLS VPN• Three mature mechanisms have been used to Inter-

AS MPLS VPN

Optioin A

Option B

Option C• Option A/B/C can build inter-AS connection of MPLS VPN, but E2E O&M

can’t be achieved by them• We hope to use single AS to solve E2E O&M problem based on the

original multiple ASs network

Inter-AS VPN E2E O&M Solutions

AS #1

AS #2

AS #3

AS #3AS

#2

AS #1

A

B

AS #3AS

#2

AS #4

AS #1

Virtual Router

Solution A Solution B Solution C

Goal of the Solutions: Transfer inter-AS to Single AS

Inter-AS Single AS

A

B

Expand backbone

AS with new routers

Expand backbone AS

with virtual routers

Build new AS with

multiple-topology

CMnet backbone

Province AProvince B

Router with default topology

Inter-AS VPN E2E O&M

Router with VPN topology

CMnet backbone

AS #1

AS #2AS #3 AS #3

AS #2

AS #4

AS #1

Province AProvince B

O&M server

Headquarter O&M

Headquarter O&M

• Build New AS for MPLS VPN Using MPLS Multiple Topology– Use multiple-topology to create a new AS which merges virtual topologies

from backbone and province ASs together– Backbone can achieve E2E O&M within the new AS

Analysis

Most of Existing network routers can’t support the virtual router by software update. It’s also a high cost solution because of substituting the hardware and software

Multiple-Topology

Virtual Router

New Construction is simple and reliable. But the high cost and the inefficient use of existing network resources are not preferable

New Construction

Considering cost and scalability, utilization and evolution of the existing network, Multiple-Topology is the preferable solution

Multiple-Topology is an easy way to deploy by software update. With MT existing network resources could be efficiently used and the network can be of resilent expansion. But the standard is not mature enough

Next Steps

• We would like to identify more application scenarios in the next version of the draft.

• We will update the protocol extensions based on the findings from the prototyping in the next version of the drafts;

• The demonstrations will be given to customers who are interested;• We would like to get more feed back from the working group for this draft.

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