The MPLS WG Archive

["Sanford, Bill" <bills@netplane.com>]

David, if I was one of those senders of the PATH messages and I turned RRO
on, wouldn't that require (unless the packet gets too big) the receiver to
put RRO in the RESV message?  The RRO on the RESV side is optional only if
the PATH message treats it as optional.  

In the end of 4.4.3

   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.

   Note that each node along the path will now have the complete route
   from source to destination.  The Path RRO will have the route from
   the source to this node; the Resv RRO will have the route from this
   node to the destination.  This is useful for network management.

   A received Path message without an RRO indicates that the sender node
   no longer needs route recording.  Subsequent Resv messages SHALL NOT
   contain an RRO.

Bill

-----Original Message-----
From: David Charlap [mailto:david.charlap@marconi.com]
Sent: Wednesday, September 27, 2000 5:12 PM
To: mpls@UU.NET
Subject: Re: RSVP-TE--RRO


Hong Liao wrote:
> 
> On Rsvp -TE page 17 the latest version 07.txt, it says that "In resv
> message, they must appear after the associated FILTER_SPEC and prior
> to the say subsequent FILTER_SPC".
> 
> I understand that the LABEL object should be in RESV message, but in
> Resv message, in either case of FF and SE, the [<RECORD_ROUTE>] is
> optional.  Also it is optional in Path message.
> 
> So RRO in Resv is optional or not?

It's absolutely optional.  What gave you any other idea?

The requirement for positioning (in the flow descriptor, after an
associated filter spec) is because a single Resv message may reserve
resources for many different senders, and a receiver may want to record
the route to each one of them.

-- David