Subject: Clarification on RSVP Restart Procedure

From: Anca Zamfir <[email-masked]>
Date: Mon, 07 Oct 2002 19:19:12 -0400

Hi,
I have a couple of questions regarding the RSVP restart procedure:

In draft-ietf-mpls-generalized-rsvp-te-07.txt, section 9.5.2. "Procedures 
for the Restarting node", one of its paragraph reads:
"In the special case where a restarting node also has a resta(r)ting 
downstream neighbor, a Recovery_Label object should be used instead of a 
Suggested_Label object."

This implies that the restarting node - N1 is able to detect that its 
downstream neighbor - N2 has also restarted, that is N1, N2 is the 
restarting order.

For the LSPs established from N2 to N1, since N2 cannot detect that N1 has 
restarted, N2 will send Path messages using the Suggested Label.
In this case N1 will not be able to differentiate the case where this 
message is a new Path message sent with Suggested Label or a Path message 
for an old LSP for which recovery happens. Is N1 expected to handle the two 
cases in the same way? If yes, why was the Recovery Label "invented" and 
why wasn't the Suggested Label considered good for the RSVP restart procedure?

Thanks,
Anca