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Context. Draft draft-decnodder-mpls-ero-rro-fastreroute-02.txt S. De Cnodder, R. Cetin, S. Van den Bosch, A. Atlas first discussed at IETF53 (Minneapolis) defines two RSVP objects: BRRO: backup record route object BERO: backup explicit route object Relation to IETF WGs
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Context • Draft • draft-decnodder-mpls-ero-rro-fastreroute-02.txt • S. De Cnodder, R. Cetin, S. Van den Bosch, A. Atlas • first discussed at IETF53 (Minneapolis) • defines two RSVP objects: • BRRO: backup record route object • BERO: backup explicit route object • Relation to IETF WGs • MPLS: it is about MPLS fast reroute • References • draft-ietf-mpls-rsvp-lsp-fastreroute-01.txt • Relation to requirements • Improves scalability of detour LSPs by a more optimal merging such that the merging nodes are close to the PLRs.
Issue 1: Support of distributed detour computation • BRRO gives path of detour to upstream PLR • upstream PLR can calculate path that merges fast with detour of downstream PLR • BERO can use loose hops • Path determination still relies on local computation BRRO = F-D B C D S A F E G
Issue 2: Object length • BRRO no longer used to make complete LSP path (+ detour paths) visible at ingress node • NMS can query each PLR using SNMP to make LSP path visible • 1 detour path in BRRO is sufficient (the path of the detour established by the immediate downstream PLR) • BERO “compressed”: • only specify relevant nodes (e.g., merging nodes) • most parts of the path are the same for multiple detour LSPs: do not repeat the same information more than once • do not specify the paths of detours that cannot merge with others
area 1 area 0 BRRO = F-D B C D A F E G BRRO = F-D E can calculate more optimal path Issue 3: Operation with inter-area LSPs • Inter-area primary LSP establishment techniques not completely stable • However, • BERO works for inter-area case • BRRO is now passed with the detour setup messages allowing it to be used by downstream nodes • Example: BRRO gives path in area 0 which can be used by the ABR(not in draft because we first need to know how inter-area LSPs are established.)
Next steps • Implementation • Further investigation of performance gain and label state for different network topologies • Confirm an efficiency/scalability trade-off between bypass and detour • Confirm consistent improvement of BRRO, even if only a single detour is passed • Further comments…? • Request to consider this to be a working group document