Support Shared Mesh Protection in MPLS-TP

IETF 83March, 2012

Ping Pan, Rajan Rao, Biao Lu (Infinera)Andrew G. Malis (Verizon)

Luyuan Fang (Cisco)Fatai Zhang, Sam Aldrin (Huawei)

Fei Zhang (ZTE)Mohana Singamsetty (Tellabs)

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Quick Background

• This is an important function in long-haul transport networks, as articulated in MPLS-TP (RFC5645)

• The design work was started a while ago• The protocol and MPLS-TP packet work have been

conducted in IETF• The circuit network-specific (e.g. OTN) work has

been conducted in ITU T15 Q9• Remarkable collaboration with all relevant parties

so far

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Shared Mesh Protection Overview

The resources on P-Q-R is sharedby multiple working LSP’s

Key properties:1. Protecting LSP’s are pre-established2. All protection related information

has been pre-computed and download – including priority data for pre-emption

3. Upon failure, a protection LSP needs to be activated at data-plane

This proposal is to specify the data-plane activation messaging sequence

and format

W1

W2

P1

P2

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Complete the switch-over within one round-trip

A

B C

D

E F G

Working LSP

4. Activation

4. Activation 4. Activation

4. Activation

1. Setup a protecting connection

2. Setup HW

2. Setup HW 2. Setup HW 2. Setup HW

2. Setup HW

3. Failure

MPLS Label GAL Header SMP commands (new channel type)

(Message processing must be very efficient to achieve rapid switch-over)

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Other Approach (draft-cheung-mpls-tp-mesh-protection)

ProtectionSegment

ProtectionSegment

• SMP messages to trigger Linear Protection• Require a special LSP between a headend to a segment• If a segment is shared for N users N LSP’s• Challenge: the scaling and maintenance of the control LSP’s

Special LSP’s for messaging

Special LSP’s for messaging

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Summary• Shared Mesh Protection is an important

function in long-haul transport networks• This proposal satisfies all the protection

requirements– Deterministic protection switch-over time– Scalable and simple to implement– Enable hardware enhancement for performance– Operate independent of control-plane

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Next Steps

• The proposal is fairly complete– Will enhance more in making it packet-friendly– Prototype work has been under way

• Requesting to make it a WG document