[80039] in North American Network Operators' Group
Re: Load balance over multiple bgp feeds
daemon@ATHENA.MIT.EDU (Will Yardley)
Thu Apr 21 20:18:58 2005
Date: Thu, 21 Apr 2005 17:15:29 -0700
From: Will Yardley <nanog@veggiechinese.net>
To: nanog@merit.edu
Mail-Followup-To: nanog@merit.edu
In-Reply-To: <20050422000627.GA6368@mitch.veggiechinese.net>
Errors-To: owner-nanog@merit.edu
On Thu, Apr 21, 2005 at 05:06:27PM -0700, Will Yardley wrote:
> On Thu, Apr 21, 2005 at 06:47:36PM -0500, Mike Hyde wrote:
[ Sorry for the self-followup. ]
> > I was wondering what everyone does to load balance over multiple
> > bgp feeds. We currently have 5 bgp feeds with 2 providers. Do you
> > just randomly pick networks, or use something like netflow to try
> > and pick the best path.
> A lot of it depends on what you're trying to balance for (cost?
> performance?), the size of each link, the type of traffic you're
> dealing with, and other factors.
Also, my experience has been in fairly content-heavy networks. Shaping
inbound traffic can be a little more difficult (lots of information on
this online). If your provider supports communities, they may allow
you to prepend selectively to certain ASes or in certain geographical
locations -- and of course you can play around with prepending.
> I've generally been able to get surprisingly accurate results in
> terms of how much traffic to send out one link or another just by
> using route-maps and some simple netflow analysis, plus traceroute /
> ping.
Probably obvious, but if your providers support communities, this can be
extremely helpful... you can often use these to do some slightly less
kludgy traffic-shaping - "prioritize traffic learned from provider X's
customers, but not from their peers", or "prioritize provider X's peers
in our city, but de-prioritize their peers in the Bay area". In addition
to internal documentation, many providers put information on the
communities they support in the routing-registry entry for their AS.
w
