[c-nsp] Reasons for "random" ISIS flapping?

[Saku Ytti]

On (2013-08-07 11:55 +0200), Peter Rathlev wrote:
 
> The device in question has a rather large-ish amount of SPD drops (42
> ppm) according to "show ibc", but other devices in the network have much

I'd try to increase hold-queue. Maybe also do SPAN for received
control-plane traffic, just to have idea what are you actually receiving
and if it looks legit.

> We actually use "process-max-time 50" generally on all these devices.
> The affected device is no different from the others in that regard. On
> the other hand might this be too low? Maybe the ISIS process needs more

I'd be comfortable with 50ms, I don't think it's too little at all.

> We only have one area and should actually be using L2 only. We hadn't
> thought it through when we decided on L1 many years ago. I'm thinking
> that L1 only or L2 only is better than L1+L2 everywhere and the only
> practical drawback of using L1 seems to be the inability to inject a
> default route. Any other gotchas we should be worrying about?

No, I fully agree with your assertion, was just curious. And of course now
if you decide that you need to add maybe metro networks with separate ISIS
domain, you're screwed.
Haven't thought about how L1->L2 migration is done and if it's possible to
do hitlessly. But certainly has no bearing to your current issue.


-- 
  ++ytti