Hi Peter, Another option for load balancing outbound traffic in your scenario would be to do some netflow analysis on your upstream ports and have a look at what the top destination ASNs your outbound traffic is flowing toward. Using this data, you can construct as-path ACLs which you can utilize in your inbound route-map on each upstream BGP session to set a higher local-preference for 'preferred' routes on each session (ie routes from ASXXX get a local-preference 1 higher than your standard upstream route local-preference), and accept the rest of the full table on each session with your normal local-preference. Using your netflow analysis you should be able to achieve a fairly equal traffic split (as you will be able to see what % of your total outbound traffic is going to which ASNs, use this data to come up with an approximated 50/50 outbound traffic split) and you will still have redundancy in place for all routes if one of the sessions drop. It would take a little more effort than simply turning on multi-pathing, but in your scenario it might be more ideal as you won't have to worry about 3bxl TCAM constraints with this method.
Cheers, Kevin Hodle On Wed, May 20, 2009 at 9:40 PM, Peter Kranz <[email protected]> wrote: > Setup is as follows; 2 edge routers, each with a BGP session receiving full > routes to the same provider router. The provider is load balancing inbound > traffic to our AS nicely, 50/50 between the edge routers.. I would also like > to load balance the outbound traffic.. I've considered adding 'maximum-paths > 2' to install the two equal paths, but an concerned about FIB TCAM impacts. > Will adding this command cause each equal cost route to take one additional > TCAM entry, i.e. full routing table x 2 > 524k TCAM limit = EPIC meltdown? > > > > Current FIB TCAM: > > L3 Forwarding Resources > > FIB TCAM usage: Total Used > %Used > > 72 bits (IPv4, MPLS, EoM) 524288 285506 > 54% > > 144 bits (IP mcast, IPv6) 262144 5 > 1% > > > > Peter Kranz > <http://www.UnwiredLtd.com> www.UnwiredLtd.com > Desk: 510-868-1614 x100 > > Mobile: 510-207-0000 > <mailto:[email protected]> [email protected] > > > > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > -- || Kevin Hodle || || PGP KeyID [0xBBDE8ED7] || fingerprint [3E1B 1F10 938E A831 8CF2 670C 1329 0B8B BBDE 8ED7] _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
