MPLS-TE FRR NNHOP protection (positioning of the NNHOP node)

[yuchenglai]

Hi All,

I have a conception question about MPLS-TE FRR NNHOP protection.  Does the NNHOP need to be along the path of the originally protected TE LSP but just downstream of the protected node?

David

[Mohamed Sobair]

Hi David,

Yes thats Correct. The Next Hop in a FRR TE LSP needs to be a long the path of the Protected TE LSP from the Headend Label Switch router to the Tailend LSR of the TE LSP.

You would normally have more than one Path OR a TE tunnel between the Headend and Tailend LSRs with FRR enabled. The Priority assigned to those tunnels selects the Primary Tunnel. and with FRR feature, if the first tunnel experience failure along the path with ANY of the intermediate next hops to the Tailend LSR of that LSP, the Secondary TE tunnel takes place with faster convergence time.

Regards,

Mohamed

[yuchenglai]

Hi Mohamed,

If you have a TE-Tunnel w/ FRR, why would you create a secondary tunnel for that TE-tunnel just for redundancy.  For the secondary tunnel to be truely redundant, I assume the secondary tunnel would need to be already fully signalled via RSVP before the failure of the Primary tunnel that is protected by FRR ?

David