[j-nsp] IS-IS POI

[Pierre Emeriaud]

Le ven. 28 sept. 2018 à 12:49, Saku Ytti <saku at ytti.fi> a écrit :
>
> Hey James,
>
> > Have anyone used this feature, did it actually help you pin-point the
> > source of an IGP issue?
>
> I doubt many people have ever encountered the problem.
>
> The problem is rogue or misconfigured ISIS speaker with duplicate
> address. This ISIS speaker can re-advertise every LSP with superior
> SEQ or even MAX_SEQ.

a subsidiary of $work had an issue with rogue purges. But it wasn't a
rogue equipment. It was just failing in the (very) wrong way. Their
network went down for several reaaaally looong hours.

> Outcome of rogue ISIS speaker advertising MAX_SEQ is that you need to
> first remove the rogue speaker and then reload whole network
> simultaneously or renumber every ISIS speaker. If you reload all
> network except one, whole network will relearn the bad information
> from the remaining speaker once it comes up.
>
> In this failure mode this feature would help to find the rogue ISIS
> speaker, so looks sensible feature to me, even when very partial
> support it will limit limit the domain where the suspect exists. I've
> personally not used it, and very much hope I'll never have need for
> it.

Yes. I really want to never need such a feature, but as this scenario
is what our ops nightmares are fueled with, I asked for some more
monitoring of purge messages, so as updates per seconds and some other
metrics.