Re: How to progress DSTE, particularly p -> TE-Class[i] = {CT, p}

[Jim Boyle <jboyle@pdnets.com>]

It sounds like it comes down to an argument of speed of progress -v-
correctness. 

In the interest of speed and correctness, maybe the following addition
to the dste-proto draft would work:

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// constrait based routing becomes section 8
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7.  Diffserv TE support with MPLS extensions.

There are a number of extensions to the initial base specification for
signalling [RSVP-TE] and IGP support for TE [OSPF-TE][ISIS-TE].  These
include enhancements for generalization [GMPLS-SIG][GMPLS-ROUTE], as
well as for additional functionality such as LSP hierarchy
[HIERARCHY], link bundling [BUNDLE] and fast restoration
[REROUTE]. These specifications may reference how to encode
information at certain priorities, as well as how to treat LSPs at
different priorities.

In order for an implementation to support both this specification for
Diff-Serv-aware TE, and a given MPLS enhancement such as those listed
above (but not limited to those), it must treat references to
"priority" in a generalized manner, such as it is used in this
specification.  Additionally, current and future enhancements may
include specification for how they interact with Diff-Serve-aware TE.

Encoding of values of priority in signalling or at a priority for
route-information should be considered to be an encoding of the same
information at the equivilant TE-Class.  For instance, if an
enhancement advertises parameters for routing information at priority
N, it should actually advertise the information for that parameter at
TE-Class N.  On receipt, Diff-Serv-aware TE routers should interpret
it as such as well.

When there is discussion on how to comparatively treat LSPs of
different priority, a Diff-Serv-aware will treat the priority in this
context as the priorities associated with the TE-Classes of the LSPs
in question.

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Non-normative reference additions.

[GMPLS-SIG] Berger et. al., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Functional Description", RFC3471

[GMPLS-ROUTE] Kompella et. al., "Routing Extensions in Support of
Generalized MPLS", draft-ietf-ccamp-gmpls-routing-05.txt, work in
progress.

[BUNDLE] Kompella, Rekhter, Berger, "Link Bundling in MPLS Traffic
Engineering", draft-ietf-mpls-bundle-04.txt, work in progress.

[HIERARCHY] Kompella, Rekhter, "LSP Hierarchy with Generalized MPLS
TE", draft-ietf-mpls-lsp-hierarchy-08.txt, work in progress.

[REROUTE] Pan et. al., "Fast Reroute Extensions to RSVP-TE for LSP
Tunnels", draft-ietf-mpls-rsvp-lsp-fastreroute-03.txt, work in
progress.

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