The MPLS WG Archive

[Francois Le Faucheur <flefauch@cisco.com>]

Lou,

At 12:04 24/07/2000 -0400, Lou Berger wrote:

>
>How about including an "SHOULD" level option that allows a MPLS-DS LSR to 
>treat LSPs signaled without the DIFFSERV object as non-DS LSPs?  I think 
>this would address this issue.
>

Just to be sure I understand the proposal:
The text would say that when there is RSVP signaling without the Diff-Serv object, the LSR SHOULD (instead of MUST) interpret this as a request for an "E-LSP using Preconfigured EXP<-->PHB Mapping".
(which would imply that if there's a really good reason to do otherwise - eg. to maintain some pre-Diff-Ext QoS support - then you could do so).

If that's the proposal, that works for me.

>(BTW which heterogeneity and transition issues are you addressing with the 
>objects proposed in your new draft?)
>

The new draft focuses on Diff-Serv-aware Traffic Engineering whereby different bandwidth constraints can be applied to different Diff-Serv Classes. This involves advertising more than one "unreserved bandwidth" information in IGPs and using the appropriate one for path computation for each Diff-Serv Class. Also, it involves performing admission control over different bandwidth pools at LSP set-up. 
The transition situation we focused on is when migrating from existing TE (which we refer to as "Aggregate TE") to "Diff-Serv-awrae-TE". More precisely , the migration situation involves a mix of:
	- "old" LSRs which are Diff-Serv capable and (Aggregate) TE capable (ie support a single bandwidth constraint, aka single bandwidth pool, aka compute the same route regardless of the Diff-Serv Class transported)
	- "new" LSRs which are Diff-Serv capable and Diff-Serv-aware-TE capable (ie support a multiple bandwidth constraints, aka multiple bandwidth pools, aka may compute different routes depending on the Diff-Serv Class transported).

Note that we are not proposing new objects just to address this transition issue. Rather we are saying that the new objects/procedures that get defined for Diff-Serv-aware-TE MUST satisfy this migration goal.

Hope that clarifies

thanks

Francois

>Thanks,
>Lou
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Francois Le Faucheur   
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