1. 1 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

2. 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. 3 Scenario 1: per-AS TE LSP Path Computation AS1 ASBR2 ASBR4 ASBR1 AS2 ASBR3 B A ASBR5 AS2 ASBR6 ASBR8ASBR7 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) … ERO expand (partial path computation) Semi-dynamic path computation – HE crankback in case of Call admission failure Option for ASBR discovery

4. 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.txt proposes 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. 5 Scenario 2: distributed path computation server AS1 ASBR2 ASBR4 ASBR1 AS3 ASBR3 B A ASBR5 AS2 ASBR6 ASBR8ASBR7 A selects a PCS (static configuration or dynamic discovery (IGP Extensions)) ** * PCC-PCS sig request (draft-vasseur-mpls-computation-rsvp-03.txt) ASBR1 build a virtual SPT (the shortest path is built using a backward recursive computation) Shortest path satisfying the constraint from any ASBR in AS3 – Path1: ERO1, c1 Path2: ERO2, c2 Virtual SPT The resulting shortest path is provided to ASBR1 Virtual SPT

6. 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 draft-vasseur-inter-AS-TE-00.txt IETF-56 San Francisco 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

7. 7 Conclusion Next step: start discussion …