[Babel-users] CRXN/DN42: interconnecting overlay networks with Babel and BGP

[Juliusz Chroboczek]

> I think the answer should be that no matter how you mess with the metrics
> babel should still remain loop-free, right?

Both Babel and BGP should remain loop-free whatever you do.  However, when
you redistribute routes between protocols, there's no guarantee that the
union of the two graphs remains loop-free.

So if you're not careful you could end up in a situation where Babel
maintains a loop-free forwarding graph, BGP maintains a loop-free
forwarding graph, but there exists a loop that goes Babel -> BGP -> Babel.

-- Juliusz