Transcript Generalized MPLS (GMPLS) Support For Metro Ethernet

BFD for MPLS LSPs Enhancement
draft-chen-mpls-bfd-enhancement-01.txt
Ning So ([email protected])
Mach Chen ([email protected])
Ville Hallivuori ([email protected] )
MPLS - 77th IETF Anaheim
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BFD Enhancement Overview
Relax the rule of “One BFD session per FEC” to “One BFD session per LSP or pair
of LSPs”.
Reduce the number of BFD sessions
Allows LSP ingress to signal the desired return path for any BFD session
Utilizes the Return-Path-Specified capability defined in RPS-LSP-PING (draft-chen-mplsreturn-path-specified-lsp-ping)
Only one BFD session is provisioned onto a bidirectional Path
Controlled by a new TLV: Session Control TLV
The node with larger IP SHOULD initiate the signaling
Allows one BFD session to be used as protection trigger for a pair of
unidirectional LSPs
The forwarding and returning path of the LSP pair are congruent
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Use Case for Enhanced BFD
Diverse Transport Paths
…
100GE
NODE B
…
NODE A
…
…
ROUTER1
100GE
ROUTER 2
Uni-Directional LSP
…
…
Bi-Directional LSP
Multiple LSP
Use case condition description
multiple uni-directional LSPs exist between Router 1 & 2, carrying different type of services
Multiple bi-directional LSPs exist between Node A&B, carried on diverse physical transport paths
Return-path-specified BFD enhancement can simplify the BFD session provisioning
process
No need to log into both routers in order to deterministically select the physical paths on which the
operators want to detect failure
In this case, the operator can provision 3 BFD sessions onto 6 uni-directional LSPs (3 in each direction)
where those LSPs are carried on 3 diverse path.
The time savings can be very significant when activating a new router in a large network where fullmesh LSPs provisioning are required to support the services (e.g. VPLS) carried on the new router
Return-path-specified BFD enhancement can simplify the trouble shoot process
No need to log into both routers reduces customer down time and increase network availability
It is especially useful when the remote router is not accessible (belong to another carrier or all login
sessions occupied), or the remote router is of different equipment vendor on which the trouble shooting
operator is not trained
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Differences between version 0 and version 1
Following changes were made on Session establishment
section based on the comments from Vishwas Manral:
Proposed to use Source Address TLV to carry the IP address of the
initiator when IP forwarding is disabled (in MPLS-TP scenario) for IP
address comparison
Clarified the process of BFD control packets when a single BFD
session is provisioned to a bidirectional path
• the initiator (ingress) MUST not send BFD packets before echo reply
received
• Ensure that the BFD session is complete for both directions before any
BFD control packets are sent over the session
A new section (Section 5 Encapsulation) is added
Describes how to encapsulate the BFD control packets transmitted
over the return LSP
Other minor editorial changes for error correction and
clarification purposes
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Acknowledgements
Authors would like to thank Greg Mirsky,
Vishwas Manral, Adrian Farrel, Peter
Ashwood-smith and Xinchun Guo for their
reviews and great input
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Next Step
Should this draft progress within MPLS WG
draft or should it be moved to BFD WG?
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