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