[103974] in North American Network Operators' Group
Re: [Nanog] Cogent Router dropping packets
daemon@ATHENA.MIT.EDU (David Coulson)
Mon Apr 21 12:03:51 2008
Date: Mon, 21 Apr 2008 12:02:49 -0400
From: David Coulson <david@davidcoulson.net>
To: Joe Greco <jgreco@ns.sol.net>
In-Reply-To: <200804211541.m3LFfLkM035688@aurora.sol.net>
Cc: nanog@merit.edu
Errors-To: nanog-bounces@nanog.org
Joe Greco wrote:
> For those unfamiliar, Cogent has a system where you set up an EBGP peering
> with the Cogent router you're connected to, for the purposes of announcing
> your routes into Cogent. However, these are typically smaller, aggregation
> class routers, and do not handle full tables - so you don't get your routes
> from that router. To get a full table FROM Cogent, you need to set up an
> EBGP multihop session with them, to their nearest full-table router. I
> believe they actually do all their BGP connections in that manner.
Depends on the service you purchase. Fast Ethernet seems to be delivered
as eBGP-multihop (the first hop is just a L3 switch), however DS-3 is
handled as a single BGP session. I'm not sure if GigE or SONET services
are handled as multihop or not.
Probably all depends what hardware they have at each POP....
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