I don't have machines to test this yet. But I would like to ask what would happened if I set up multiple links between an IS to other IS?
Something like this one:
-- --Link 1-- --
--- |R1| --Link 2-- |R2| ---
-- --Link 3-- --
All links are point-to-point. Will I see three adjacencies on them? Or they'd just pick one and only that one will be active?
I have tried this on OSPF, it seems OSPF could learn multiple adjacencies link to same router. I'm not sure if ISIS is capable to do so.