Subject: Between OSPF RSVP...

From: "[email-masked]" <[email-masked]>
Date: Wed, 12 Mar 2003 11:42:02 +0100

Hi all,
I' m interesting in protection/restoration (P/R) mechanisms and after having read some works, i' d like to do some observations.
In a TE path protection scenario, there are works dealing with the use of RSVP-TE messages to signal, in example, 
a link failure.
But could it have sense this other way of recovery?
...After a detection of a failure, OSPF ( OSPF-TE ) uses the flooding mechanism to advertise the all network that one link is broken
( ... using opaque LSA? ); then all nodes, receiving the LSA with this information, could compute an analysis of what LSPs ( LSP having source in that node ) are interested by the failure. Then, in example, each node that wants to do restoration in a MPLS scenario could make a Label Switching if there is a Backup Path available. 
This approach has some problem:
- a faster trigger on OSPF in detecting failure, since HELLO mechanism is slow;
- the prioriting of the sequence ---flooding LSA--- and then ---computing SPF algorithm--- to do faster;
- the adding of intelligence in each node to do the Switching.

I know that these are only some observations containing ( i hope few ) errors and that aren't complete, but since i haven' t found any P/R mechanisms in a TE scenario using OSPF ( or any optimized version of this ), i' d like to make you a question:
is this a possible way of study ( as an alternative to RSVP signalling ) or is completely wrong and out of all standards?

Thanks in advance for your kind answers and observations.

Giovanni Di Giacomo