The MPLS WG Archive

["Vijayanand C - CTD, Chennai." <vijayc@ctd.hcltech.com>]

Hello all,
I have a question on the signalling funcionality in CR LDP for local repair.

Consider the topology below.

                     ---------- C ------------ 
                     |                         |
          --A ---  B ---------------------- D--



Assume a tunnel exist across A-B-C-D( loose ER Hops as B D  )  Suppose a
route update happens at node B with the next hop for node D being node D
itself(may be due to BW constraints the CSPF has taken this decision and LSP
is now going straight through). At this point node B sends a release along
CD to release the old segment and a request to D.  In case, the request
(which has to travel just one hop) arrives earlier than the release( which
has to be processed at CR LDP at node  C ) at node D, then the request would
be rejected by node D because the request is not a mdification request but a
request for existing LSP itself !!

This situation would occur more consistently if the original path that is
released were more longer than the new path.	

How does CR LDP handle such a signalling scenario? 

Thanks in advance,
Regards,
Vijay