[c-nsp] stuck transit LSP's

Lukas Tribus luky-37 at hotmail.com
Mon Nov 16 09:41:59 EST 2015


> Hey All,
>
> For the purpose of this issue / explanation.. We run lots of brocade LSP's over top of a Cisco MPLS network.
> Mostly of ASR 1K's and 7600's - all running LDP and RSVP dual stack for transiting these LSP's. brocade MLX / CER's / CES's on the edge.
> The Cisco routers are simply transiting the LSP's.
>
> Everything works as expected except after we see a OSPF topology change. For example a carrier link drop and come back.
> After this event, we see the odd LSP just sit in a up/down state. As in over a hundred FRR around the issue yet one of 2 just don't.
> It seems the cisco is still signals back to the brocades that the tunnel is ok - when its clearly not. The brocades all indicate tunnels are fine.
> The tunnel remains down and each end believes its up. The only identifications we see is the 'show mpls traffic-eng tunnels' is its up/down - on the cisco transiting LSP device.
> We see next to no pattern and the issue when repeats doesn't always affect the same LSP's.
>
> The only resolution is to tear the tunnel down manually and bring it back. Re-optimisation doesn't work.
>
> Curious if anyone has seen an issue like this ? or any suggestions ?

This happens on both ASR1k and 7600 midpoints? In different releases?

What about the requested tunnel bandwidth, is it static or are you using
something like auto-bw? The requested bandwidth may be the pattern you are
looking for (thinking of CSCsg44555).


Lukas

 		 	   		  


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