valley free routing?

Valdis.Kletnieks at Valdis.Kletnieks at
Wed Mar 5 21:00:44 UTC 2014

On Wed, 05 Mar 2014 15:23:55 -0500, William Herrin said:
> Hi folks,
> Can anyone tell me about a situation in which a route which was not
> valley free was not a result of a misconfiguration or a bad actor? For
> those who don't recall the terminology, a network path is valley free
> if it crosses exactly zero or one free peering links when traveling
> between the two endpoints.

Assume 3 providers A B and C, where you have a single-homed customer on A and a
single-homed customer on C, and A and C don't peer.  Traffic may end up going
thorugh an A-B peering and a B-C peering. And whether A-B and B-C are a free
peering or a paid transit is a business deal, outside the scope of BGP, unless
you want to abuse communities...

Are A and/or C "bad actors" for not peering? Jury is still out on that one.
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