[c-nsp] BFD flapping on 6509 SUP720-3BXL

[Peter Rathlev]

On Wed, 2012-02-29 at 13:37 -0500, Ross Halliday wrote:
> I'm getting a load of BFD flaps on all ISIS (MPLS) links to a specific
> PE router. The router core-site_1-c6509 is at a central site that
> provides connectivity for our MPLS network such as linsite_3 to our
> Internet edge router, subscriber termination, VoIP access, etc. Based
> on my searching I'm guessing that is CPU load on core-site_1-c6509 is
> too high or erratic for the low BFD timers. It's doing all of this
> with a SUP720-3BXL. 

What software are you using? SXF is said to be terrible regarding BFD,
SXH/SXI a little better.

...
> configured with "bfd interval 50 min_rx 50 multiplier 4", yet these
> are not experiencing the same flaps.

I think this is much too low for the Sup720. We're using "bfd interval
100 min_rx 100 multiplier 5" without any problems on SXI.
> 
> The interfaces with the flaps don't have any errors, and links whose
> fibers have nothing to do with each other are sometimes blowing up at
> the same time (see below). The one thing I do see are some QoS drops.

Maybe the output from "show interface GiX/Y | incl drop" and "show ibc |
incl spd drop" would shed light on it.

-- 
Peter