Subject: Re: draft-ietf-mpls-diff-ext-07.txt

From: Curtis Villamizar <[email-masked]>
Date: Wed, 01 Nov 2000 19:05:03 -0500

In message <[email-masked]
>, "Eleonora Manconi (TEI)" writes:
> Hi all, 
> I have some question about draft-ietf-mpls-diff-ext-07.txt:
> -in E-LSP method, PSC is inferred from EXP field. The question is: PSC means 
> only priority or I can infer also other information like loss, delay, etc. fr
> om EXP field? Are these information meaningful for MPLS? 

With unsignaled E-LSP a provider may confiugre any mapping of EXP to
PHB and must set any queueing preference, queue weights or drop
preferences associated with each PHB by configuration only.

With L-LSP or signaled E-LSP, the PSC is explicitly signaled and the
provider may either configure queueing preference, queue weights or
drop preferences directly or configure a mapping from the sum of
reservations of given types to queueing preference, queue weights or
drop preferences (though I can personally only see the use in mapping
sum of reservations at a PSC to queue weight).

> -In which kind of scenarios it is (does it is?) meaningful the coexistence of
>  L-LSP and E-LSP?

First your routers have to support both.  Using unsignaled E-LSP might
be simplest if it meets your requirements.  Otherwise using signal
E-LSP seems most flexible but using L-LSP is best if some links are
ATM or FR.

> Thank you in advance.
> Eleonora.

Curtis