[119224] in North American Network Operators' Group
Re: about interdomain multipath routing.
daemon@ATHENA.MIT.EDU (Doug Lane)
Tue Nov 10 04:11:51 2009
In-Reply-To: <63ac96a50911091950t719a3267lfc1c289d97ce5216@mail.gmail.com>
Date: Tue, 10 Nov 2009 09:10:59 +0000
From: Doug Lane <laned1@gmail.com>
To: Matthew Petach <mpetach@netflight.com>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Tue, Nov 10, 2009 at 3:50 AM, Matthew Petach <mpetach@netflight.com> wro=
te:
> I've outlawed the use of multihop eBGP for load-sharing here; when we get
> multiple links off the same router to a peer or upstream, they are config=
ured
> with multipath. =A0We've got hundreds of BGP sessions across the network
> configured with multipath on them.
>
Do you use iBGP multipath as well to load-balance between links on
different routers?
I know eBGP multipath is fairly common, but I wonder how many are
using iBGP multipath as well. I doubt any carriers would support it,
so it's probably only useful for load-balancing outbound traffic. The
problem with eBGP multipath alone is that you might want to terminate
circuits from a given carrier on two different routers for redundancy
reasons, but that precludes any load-balancing with eBGP multipath.
Obviously your network has to be designed with equal-cost paths for
iBGP multipath to be of any value.
-Doug
