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Jean-Philippe Vasseur – Cisco Systems Raymond Zhang - Infonet

IETF- 56 – TE WG- SAN FRANCISCO Inter-AS MPLS Traffic Engineering draft-vasseur-inter-AS-TE-00.txt. Jean-Philippe Vasseur – Cisco Systems Raymond Zhang - Infonet. draft-vasseur-inter-AS-TE-00.txt IETF-56 San Francisco.

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Jean-Philippe Vasseur – Cisco Systems Raymond Zhang - Infonet

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  1. IETF- 56 – TE WG- SAN FRANCISCOInter-AS MPLS Traffic Engineeringdraft-vasseur-inter-AS-TE-00.txt Jean-Philippe Vasseur – Cisco Systems Raymond Zhang - Infonet draft-vasseur-inter-AS-TE-00.txt IETF-56 San Francisco

  2. Inter-AS MPLS Traffic Engineering requirements draft: draft-zhang-mpls-interas-te-req-02.txt (TE WG) • Inter-AS MPLS Traffic Engineering (solution draft): draft-vasseur-inter-AS-te-00.txt (WG to be decided once inter-AS reqs draft adopted as a WG doc) Scenario 1: per-AS TE LSP Path computation Scenario 2: distributed path computation server draft-vasseur-inter-AS-TE-00.txt IETF-56 San Francisco

  3. ERO expand (partial path computation) ERO expand (partial path computation) Scenario 1: per-AS TE LSP Path Computation ASBR1 ASBR2 ASBR5 ASBR6 B A ASBR3 ASBR4 ASBR7 ASBR8 AS2 AS2 AS1 TE LSP defined as a set of loose hops: Pref1: A-ASBR1(L)-ASBR2(L)-ASBR7(L)-ASBR8(L)-B(L) Pref2: A-ASBR3(L)-ASBR4(L)-ASBR7(L)-ASBR8(L)-B(L) … Semi-dynamic path computation – HE crankback in case of Call admission failure Option for ASBR discovery

  4. Scenario 1: additional drafts …. • Inter-AS TE LSP reoptimization (MUST in the requirement draft) draft-vasseur-mpls-loose-path-reopt-01.txt proposes a set of mechanisms allowing: A TE LSP Head-End LSR to trigger on every LSR (whose next hop is a loose hop) the re evaluation of the current path in order to detect a potential more optimal path (performed via signalling) An LSR whose next hop is a loose-hop to signal, upon request or not, to the TE LSP head-end whether or not a better (lower cost) path exists If and only if at least a better path exist in an area/AS, the HE LSR triggers a non disruptive TE Reroute (Make before break). • ASBR Node protection (with MPLS TE Fast Reroute “facility backup” (MUST in the requirements draft) • draft-vasseur-mpls-nodeid-subobject-00.txtproposes to specify an additional flag of the RRO IPv4/IPv6 sub-object used for the backup tunnel selection for inter-AS TE LSP protected by MPLS TE Fast Reroute (“Facility backup”) in case of ASBR node failure

  5. PCC-PCS sig request (draft-vasseur-mpls-computation-rsvp-03.txt) Shortest path satisfying the constraint from any ASBR in AS3 – Path1: ERO1, c1 Path2: ERO2, c2 A selects a PCS (static configuration or dynamic discovery (IGP Extensions)) The resulting shortest path is provided to ASBR1 Virtual SPT Scenario 2: distributed path computation server * * ASBR1 ASBR2 * ASBR5 ASBR6 B A ASBR3 ASBR4 ASBR7 ASBR8 AS2 AS3 AS1 ASBR1 build a virtual SPT (the shortest path is built using a backward recursive computation) Virtual SPT

  6. Summary • Scenario 1: per-AS TE LSP Path computation • - No impact on RSVP/IGP scalability, • Semi-dynamic, • Small set of protocol extensions required, • No optimal end to end path • Diverse path computation not always possible (Path protection, load balancing) • Call set up failure, • Support of end to end reoptimization (timer/event driven) • Support of FRR Bypass for ASBR protection • Scenario 2: distributed path computation server • No impact on RSVP/IGP scalability, • Dynamic, • - Implementation more complex, • Optimal end to end path • Diverse path computation always possible (Path protection, load balancing) • No call set up failure • Support of end to end reoptimization • Support of FRR Bypass for ASBR protection • TE LSP local protection recommended Both scenario 1 and 2 are compliant with the set of requirements defined in draft-zhang-mpls-interas-te-req-02.txt draft-vasseur-inter-AS-TE-00.txt IETF-56 San Francisco

  7. Conclusion • Next step: start discussion …

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