The MPLS WG Archive

[Anouk Rocher <anouk@ureach.com>]

David, Senthil

First, thanks for your replies. Comments inline.

>The resources reserved are in the FLOWSPEC sent from the egress router
>to the ingress router.  This FLOWSPEC may be one of three kinds of
>intserv classes: Null (meaning best-effort), Controlled-Load, or
>Guaranteed Service.

While trying to do vanilla Traffic Engineering which for quite
a few people seems to finding a path which guarantees a certain bandwidth
for an LSP while reducing hopcount (and I do realize there are many
other possibilities), clearly Null intserv class is not interesting.

Is there an expectation from Network Operators and Service Providers
that they would use one of "Controlled Load" or "Guaranteed Service"
over the other?

>
>The TSPEC in the Path message is used by the ingress router to inform
>the egress router of what it wants to reserve.  Under most MPLS
>implementations, the egress router will try to reserve this amount,
>although it is possible for policy decisions to choose a lower amount.
>The ADSPEC in the Path message, if used, serves two purposes.  It
>gathers information about the network along the path so that the egress
>router will have an idea of what resources are available, and it may be
>used to request a particular kind of intserv class for the FLOWSPEC.

This definitely helps me some. The question I have here is that while 
ADSPEC is used for regular RSVP, is it still used in MPLS networks which
are using RSVP only for traffic engineering?

Or more generally, since several RSVP features are not relevant to MPLS/TE
is there some conventional-wisdom/informational-document out there
which specifies what RSVP features can be safely turned off or not 
implemented when doing MPLS/TE.


>
>This is all straight RSVP and has nothing to do with traffic
>engineering.
>
>Traffic engineering is made possible via the new objects introduced in
>RSVP-TE.  Specifically, SESSION_ATTRIBUTES and EXPLICIT_ROUTE.

I understand this. However the LSP constraints may included bandwidth
as well as other things which come via RSVP. Which is why I was asking
the question.

>
>-- David

Anouk

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