Pseudo-Wire Protection Ping Pan ppan@hammerheadsystems.com IETF 65

Why? Tunnel-1 (BW1) Node 2 Node1 Tunnel-2 (BW2), backup Tunnel-1 PW (Important traffic) Tunnel-1 (BW1) Node 2 Node1 PW (Best effort) Tunnel-2 (BW2), backup Tunnel-1 Switch-over Conventional mechanism (e.g. MPLS FRR) would work, if Tunnel-1 and Tunnel-2 have the same bandwidth (i.e.,BW1 = BW2) All PW’s are equally important Otherwise, if BW2 < BW1, Important traffic may get dropped/delayed during network failure PW protection: Each PW needs to have its own “importance” and QoS level During switch-over, preempt others if necessary

Design Considerations (1) Need to work in single and multi-segment environment Work with Generic ID FEC only Working and protection PW’s must be uniquely identified But make the use of AII/AGI may not be a good idea working protection Need to know what to process

Design Considerations (2) On Backup Path Determination Carrying “ERO” should be optional Use hop-by-hop forwarding for the working PW Get “RRO” information from “PW Switching Point TLV (SP-TLV)” Build the protection PW base on SP-TLV May use SP-TLV for loop-detection On CAC at each hop Should be optional depending on traffic type Other relevant protection information: 1:1 or 1:N: need to validate the need of 1:N Fate-sharing: useful in multi-hop applications Hot-standby vs. cold-standby

Protocol Extension Protection-TLV PW Status: Everything else: Setup and Holding Preference Levels Protection Type: hot or cold standby Schemes: 1:1 or 1:N Flags: Fate-sharing allowed Per-hop BW CAC required Reference ID: unique identify working and protecting PW’s PW Status: Bad message, no bandwidth etc. Everything else: Keep as it is AII/AGI must be the same on all working and protecting PW’s

How does it work? Protecting PW Working PW Node1 Node 2 Node 3 Run MHOP PW for working and protection PW setup Use SP-TLV for loop detection Use Protection-TLV and SP-TLV to forward working and protection PW’s Forward failure status if not working Run the Generic FEC procedure to setup the working PW Run the Generic FEC procedure to setup the protection PW When working, pointing user traffic to the protecting PW During failure (learned from BFD etc.), switch over Preempt traffic when needed… Send out Label Mapping and setup the working PW When working, setup the protecting PW (base on SP-TLV…) When working, pointing user traffic to the protecting PW During failure (learned from BFD etc.), switch over Preempt traffic when needed…

Next Step This proposal works in both single-segment and multi-segment cases Like to Continue to gather feedback Iron out the details with others Make this into a WG Working Document THANK YOU ALL