[nsp] eBGP routes not balancing

jlewis at lewis.org jlewis at lewis.org
Mon Nov 17 21:05:45 EST 2003

On Mon, 17 Nov 2003, Jeff Chan wrote:

> After enabling "bgp bestpath compare-routerid" and resetting the
> sessions, most of the traffic went to the peer with the lower
> numerical address (ID), which again is unbalanced.  So I've
> disabled compare-routerid and will probably reset all the
> sessions late at night with "clear ip bgp all" in the hopes
> that the ages of the routes will then be close enough, since
> they're all cleared and re-learned at the same time, to
> result in traffic that is closer to balanced.

That's a really ugly solution, IMO, and anytime one of your transit peers 
resets, you're going to be screwed balancingwise.  By clearing all your 
BGP sessions simultaneously, you're creating a brief outage and you're 
really going to tax the CPU in your router...perhaps inducing all sorts of 
odd IOS bugs while the sessions are coming back.

Put "bgp bestpath compare-routerid" back and then use an input route-map
on the peer you're sending most/too much traffic to.  I usually prepend
their ASN one or more times to make certain as-paths less attractive, thus
discouraging traffic to those networks from using the fuller link.

 Jon Lewis *jlewis at lewis.org*|  I route
 Senior Network Engineer     |  therefore you are
 Atlantic Net                |  
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