Subject: Question of RRO behavior

From: Ganesh Murugesan <[email-masked]>
Date: Fri, 26 Jul 2002 14:03:38 -0400

Hi,

Section 4.4.3 of RFC 3209 quotes that

   When the destination node of an RSVP session receives a Path message
   with an RRO, this indicates that the sender node needs route
   recording.  The destination node initiates the RRO process by adding
   an RRO to Resv messages.  The processing mirrors that of the Path
   messages.  The only difference is that the RRO in a Resv message
   records the path information in the reverse direction.

Since there is no MUST or SHOULD used to describe the behaviour of
the destination on receiving a PATH message with an RRO, what is the
expected
behavior on the node receiving the RESV message from the destination 
if the destination decided not to place a RRO object in the RESV message.

Should the Phop node drop the RESV message or forward the RESV message
without an RRO,  or add a RRO to the outgoing RESV message or send a
ResvErr downstream (with what error code/value)?

thanx
ganesh

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From: David Charlap <[email-masked]>
Date: Fri, 26 Jul 2002 15:11:31 -0400

> ResvErr downstream (with what error code/value)?

I would have it process the Resv message normally, and not add an RRO to it.

You don't want to reject the Resv, because you don't want non-support of 
RRO to break LSP setup itself.

You also don't want to add an RRO where none existed because the ingress 
node, upon reading that RRO, might think the LSP has ended on the Phop 
node instead of on the egress node, and it might take inappropriate 
action as a result.

-- David