On Sat, Mar 13, 2004 at 04:19:40PM -0800, Will Yardley wrote:
On Fri, Mar 12, 2004 at 11:37:25PM -0500, Joe Abley wrote:
On 12 Mar 2004, at 23:24, joe mcguckin wrote:
I suspect that each FE goes to a different AS...
In that case, sample/count outbound traffic volumes by (prefix/AS/AS_PATH/something), sort the resulting list, and develop an import policy based on the top N entries which shares the traffic by tweaking some other attribute to avoid the last-resort tie-break.
The tool "ehnt" is pretty useful for generating a "top" style list of ASes in order of the amount of traffic you're sending their way.
By the way, w/r/t to the tiebreaker stuff, note that (on Cisco devices) if you don't have "bgp bestpath compare-routerid" set, the route that was received first will be preferred. This minimizes route-flap, but can cause weird shifts in your traffic patterns when one bgp session or another goes down (credit goes to Mark Nagel for figuring out this one for me).
Also, check out: http://www.nanog.org/mtg-0206/feamster.html for some general guidelines, pitfalls, etc. (The paper linked from the presentation recently appeared in ACM Sigcomm CCR.) -Nick