Signaling route exclusions

["Adrian Farrel" <[e-mail]>]

All,

Below I have included a text version of the material that Cheng-Yin and I would
have used with the WG to lead a discussion on
draft-lee-ccamp-rsvp-te-exclude-route-01.txt if there had been time to slip it
in to the agenda.

Route exclusions are applicable to any MPLS (and therefore GMPLS ;-) network
where full computation of the ERO is not performed before the LSP is signaled.
This might be because loose or non-explicit routes are used, or because there
are "domains of computation" within the network. Such domains of computation
include (but are not limited to) multiple areas.

Note that multi-area signaling is now (or about to be, or might be soon, or will
be discussed soon) in the ccamp charter.

We would very much appreciate the opinions of everyone on the list both on the
usefulness and the practicality of this draft.

Thanks,
Adrian

==========


Why in the CCAMP WG?
- Charter item "Define signaling mechanisms for protection, diverse routing."
- This is an extension to MPLS but is generalized and should form part of GMPLS

Why do we need route exclusion?
- Not all signaled EROs are built entirely from strict explicit hops
   - Loose hops
   - Abstract nodes such as prefixes and AS numbers
- Not all path computation is performed offline or at the ingress
   - Protection domains
   - Limited visibility of routing information
   - George's overlay draft
   - Multiple areas (NOT a prerequisite for this draft)
- Helps address new charter item for multi-area

Changes in this version of the draft
- Updates after comments in Yokohama
   - Address chair's concerns
   - Clarify questions from the floor
   - Further refinements by authors
- New section on scope of route exclusion
- Description of relationship to (G)MPLS TE-MIB
   - Desired routes may be configured with exclusions
- Distinguish between node and interface exclusions
- Allow distinction between desired and required exclusion
- Clarify procedures for conflict between ERO and route exclusion
- Add new co-author (Stefaan De Cnodder)

Actions
- Thanks for feedback on and off the list
- We would welcome more input and contributions especially from providers
- Request to be adopted as WG document