When you say backup path for patch-protection, are you talking about path protection? I've never done path protection, but it is slightly slower than FRR with link or node protection to converge, but from what I understand it is alternative to FRR that does link and node and the path gets set up in advance, so bandwidth has to be reserved, but then again you don't have to reserve too much bandwidth, as the path is backup and its reservation should not interfere in the rservation of other primary paths.
As far as MPLS link and node and protection where FRR comes in, same thing happens. The path gets set up in advance and you can protect multiple links with one backup path in case of link and node protection and if you do MPLS TE mesh groups (of which I only read about and see in the lab) you can have relatively easy configuration, but possibly too much troubleshooting. So, the path is set up in advance and you can either set this up to protect until the primary tunnel fixes itself through another path, or in some cases when you don't want it happen you can keep it going on the backup path until the primary tunnel fixes itself by another path going back up. So to answer your question, the path is built, and "show mpls tra fa da" (too lazy to type it up) should show you the info for the backup path. At least that is how I remember it, os the path is built and ready for failure. But I think you know all that anyway. I've only read about this, but there is a concept of using backup tunnel bandwidth protection where you can say how much bandwidth of all primary tunnels it is protecting can go on it. OPNET if you have access to it (and it is too expensive for most people to use it) is good about calculating just how to best plan for various outages and what happens when various outages in a TE environment happen. Yan ________________________________ From: Charlie Greenaway <[email protected]> To: [email protected] Sent: Monday, September 14, 2009 7:25:36 PM Subject: [c-nsp] MPLS TE Fast Re-route Hi, I have a question on MPLS TE and Fast Re-Route. I have a test network and I want to check that the behaviour I am seeing is correct. When you set-up an backup path for patch-protection, it would seem that RSVP sends signalling messages down the backup path to reserve the bandwidth. However, it does not seem to build an LSP and assign labels to it until the primary path breaks. Is this correct? Has anyone got any advice on using MPLS FRR? Thanks, Charlie G Charlie Greenaway - CCIE#11226 (Security/R&S) Solutions Architect | BT iNet | Email: [email protected] | Web: www.btinet.bt.com This electronic message contains information from BT iNet, which may be privileged or confidential. The information is intended for use only by the individual(s) or entity named above. If you are not the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this information is strictly prohibited. If you have received this e-mail in error, please let me know immediately on the e-mail address above. Activity and use of the BT iNet e-mail system is monitored to secure its effective operation and for other lawful business purposes. Communications using this system will also be monitored and may be recorded to secure effective operation and for other lawful business purposes. _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
