[j-nsp] IS-IS POI

[Saku Ytti]

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.

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.

-- 
  ++ytti