[c-nsp] BGP Multipath load balancing

[David Coulson]

I've got a couple of routers running iBGP between them, each with a eBGP 
session to an upstream provider. I'm trying to figure out a way to 
distribute the load across the two routers a little better (aside from 
pointing different hosts to each router as their gateway)

I'm assuming that iBGP isn't considered the same as eBGP when 
considering if it is appropriate multipath a route, as in the case 
below. Ideally I'd like this route to be load balanced across the two 
routers, rather than just being sent directly out the local router. 
Currently the route preference is done only by AS_PATH length, at least 
that's what I can figure out. It's routes which have identical AS paths, 
and so forth that I'm more concerned about at this point. I've been 
tweaking local-pref stuff and metrics, however it seems like they're 
more of an all or nothing deal.

core1#sh ip bgp 66.111.55.31
BGP routing table entry for 66.111.32.0/19, version 638669
Paths: (4 available, best #3, table Default-IP-Routing-Table)
Multipath: eBGP iBGP
   Advertised to update-groups:
      1          2
   2828 3356 21840
     207.166.219.2 (metric 2) from 207.166.219.2 (207.166.219.2)
       Origin IGP, metric 1000, localpref 100, valid, internal
   2828 3356 21840, (received-only)
     207.166.219.2 (metric 2) from 207.166.219.2 (207.166.219.2)
       Origin IGP, metric 1000, localpref 100, valid, internal
   174 3549 21840
     216.28.126.133 from 216.28.126.133 (154.54.4.47)
       Origin IGP, metric 1000, localpref 100, valid, external, best
       Community: 174:21000 174:22013
   174 3549 21840, (received-only)
     216.28.126.133 from 216.28.126.133 (154.54.4.47)
       Origin IGP, metric 137980, localpref 100, valid, external
       Community: 174:21000 174:22013

Any information which anyone can provide me with to get my head around 
this would be great :-)

David