IETF-%2057%20

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IETF- 57
ViennaReoptimization of explicit loosely
routed MPLS TE LSP paths
draft-vasseur-mpls-loose-path-reopt-02.txt 
Jean-Philippe Vasseur Cisco Systems Yuichi
Ikejiri NTT Communications
2

• Quick reminder
• This draft proposes a set of mechanisms to
  reoptimize loosely routed explicit TE LSPs
  spanning multiple areas/levels or ASes (as such
  it abides by the requirements for inter-AS TE
  defined in draft-ietf-tewg-interas-mpls-te-req-00.
  txt)
• 5.1.5. Re-optimization
• Once an inter-AS TE LSP has been established
  and should there be any
• resource or other changes inside anyone of
  transiting ASes, the
• solution MUST be able to re-optimize the LSP
  accordingly and
• non-disruptively, either upon expiration of a
  configurable timer or
• triggered by a network event or a manual
  request at the TE tunnel
• Head-end.
• The solution SHOULD support the ability for
  intermediate nodes to
• signal the respective Head-End LSRs of the
  existence of a more
• optimal path.
• The solution SHOULD also be such that an
  inter-AS TE LSP is
• re-signaled again (via make before break) if
  and only if a more
• optimal path exists.

draft-vasseur-mpls-loose-path-reopt-02.txt

IETF-57 Vienna
3

• Changes compared to rev -01 (presented at
  IETF-56)
• A few naming inconsistencies have been fixed,
  clarifications, more details on Head-end versus
  Mid-point reroute,
• Changes in error values for RSVP Path Error
  NOTIFY (ERROR CODE 25)
• Better Path exists has been changed from 4 to
  6
• No better path exists has been removed
• Two new error values 7 (local link maintenance
  required) and 8 (local node maintenance required)
• Change in the mode of operation
• if a better path exists, a mid-point LSR MAY not
  relay the ERO expansion request
• if no better path exists, a mid-point LSR relays
  the ERO expansion request and no longer sends a
  No better path exists Path Error message
• The previous revision used to recommend to send
  4 consecutive Path messages with the ERO
  expansion request bit set to handle lost of RSVP
  messages. Rev -02 now just recommends to make use
  of reliable messaging (RFC2961).

draft-vasseur-mpls-loose-path-reopt-02.txt

IETF-57 Vienna
4
Conclusion

• This draft proposes a set of mechanisms necessary
  to support the reoptimization of loosely routed
  TE LSP paths (inter-area/inter-AS TE LSP)
  specified as a MUST in draft-ietf-tewg-interas-mpl
  s-te-req-00.txt for inter-AS TE LSP
• There are ongoing implementation and several
  planned deployments.
• In which WG does this work fit in ?

draft-vasseur-mpls-loose-path-reopt-02.txt

IETF-57 Vienna