MPLS TE RVP FAILURE DETECTION

[Ratheesh mv]

R1 - TE HEAD-END ROUTER & R4 TE TAIL-END ROUTER

In this scenario if R3 goes down (power issue or hardware failure) LSP gets failure but how does R1 recognize that LSP is no more available due to R3 went down ? What type of message is used to bring down MPLS TE tunnel in this scenario & who would trigger this message in this scenario?

[Harold Ritter · Accepted solution]

Hi @Ratheesh mv ,

RSVP is a soft state protocol, meaning that after the LSP establishment, path and resv messages will continue to flow between the head-end and the tail-end to verify that the LSP is still functional. If R3 goes down, the path message sent by the head-end would get to R2 and R2 sends a path error back to R1 after detecting the link to R3 is down. R1 would then declare the LSP and therefore the tunnel interface down.

You can refer to the following presentation for more information:

https://packetpushers.net/rsvp-te-protocol-deep-dive/

Regards,