BGP peering question

William Herrin bill at
Tue Jul 11 19:37:26 CST 2017

On Tue, Jul 11, 2017 at 3:24 PM, Patrick W. Gilmore <patrick at>

> > Then you need to decide if you want to be a hop between those two peers
> or if you want them to serve you only. You can change your routing so that
> both providers know of your routes but you are not sharing routes between
> the two providers.
> The definition of “peering” to most ISPs would definitely not include
> becoming a “hop” between two peers. Most networks would de-peer you if you
> sent their prefixes to another peer.

Hi Patrick,

I'm given to understand this practice is common in service providers
connecting academia. Three or more service providers serving schools will
agree to pass packets even if neither school terminates at the current ISP.

This comes up in the discussion of "valley free" inter-domain routing
because it's one of the cases that forms a valley where the participating
organization is not paid for or directly donating the transiting packets.

Bill Herrin

William Herrin ................ herrin at  bill at
Dirtside Systems ......... Web: <>

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