Subject: [mpls] Fast Reroute related question according to RFC4090

From: "Asaf Henig" <[email-masked]>
Date: Wed, 28 Jun 2006 09:11:53 +0300

This question is related to the Facility Backup Method in Fast Reroute as mentioned in RFC 4090.

The RFC mentions many times that in Facility Backup method a router doesn’t know it is an MP (merge point) until the link connecting it to the PLR (incase of link protection) is down. The RFC explains that when such an event occurs the MP should wait for PATH messages to arrive from the backup path which help the MP connect between the protected LSP and the backup session.

According to the above scenario, is it correct that after the link is down the MP should handle three different types of PATH messages which arrive from the backup direction?
     1) The original protected lsp path messages which are now encapsulated in MPLS.

     2) New path messages, which are also mpls encapsulated, initiated by the PLR and have almost the same session identifier as the path messages of the protected lsp but with a different sender id.

     3) The original backup path messages which simply maintain the backup tunnel which starts at the PLR and ends at the MP.

Thanks for your help. 

Asaf Henig. Software engineer 

MRV International

_______________________________________________
mpls mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/mpls