The MPLS WG Archive

[David Charlap <David.Charlap@marconi.com>]

Dipak wrote:
> 
> According to RFC 3209 section 4.2.4 says that "
> 
>    If a LABEL_REQUEST object was not present in the Path
>    message, a node MUST NOT include a LABEL object in a Resv
>    message for that Path message's session and PHOP."
> 
>    But, in section 3.1, the PATH message format shows LABEL_REQUEST
>    as not an optional object.
>
> Is not it contradictory? Or, should I take it as a way to make
> RSVP-TE behave as vanilla RSVP, if somebody wanted to do so?
> Can anybody help me out of this dilemma?

Two different situations here.

If this is an RSVP-TE session (defined as using one of the new LSP-based
C-Types for the SESSION object), then LABEL_REQUEST is mandatory.  It is
not required for other session types.  (I don't think LABEL_REQUEST is
illegal for non-LSP session types, but it is of questionable utility.)

When generating a Resv, a LABEL must be included if the corresponding
Path had a LABEL_REQUEST.  This is always true for LSP sessions.  It is
probably not true for non-LSP sessions.

-- David