Currently, I BGP load-share across an OC-12 Link and a Gig-E circuit. I also use weights to help influence my outbound traffic across these two links.
My questions are.....First, I am fixing to hook up another Gig-E circuit from another service provider, in which I will have to peer with. Are there any issues with peering with 3 providers??
Second...I need to load share my Gig-E connections, while only utilizing the OC-12 for inbound and outbound traffic if both Gig-E circuits were to fail. These were my thoughts on doing this....I would just set lower weights on all the routes coming from both providers off of the Gig-E circuits via route maps, to manipulate traffic flow outbound through both the Gig-E circuits first. I would also "poison" my routes via as-path prepend towards my OC-12 peer as to prevent inbound traffic, unless both Gig-E circuits were down.
Does any of this sound right? My thinking may be way off? Any help would be greatly appreciated! Thanks!!!
the maximum-paths 2 allow to install two BGP advertisements in the routing table if they share the first "N" parameters in the BGP path selection.
Actually, there could be a big impact on the CEF table because all routes with two next-hops will have a bigger entry to accomodate the two paths so I apologize it should be tested in a lab not in production.
If these memory issues don't happen you could get a more fair load-balancing.
Without using this command for all the routes that are "in common" between ISP1 and ISP3 only one path is chosen.
If I've understood correctly you are doing load-balance by using different weights for different prefixes in the IPv4 space with a route-map for each neighbor.
This can provide good results for the high number of IP prefixes and without the risk to increase CEF entries sizes with double paths.
Currently we have three upstream providers on a GSR and the two 6500 with sup720 3BXL receive the result of choices made by the two 12000 border routers so they are a little more protected.
On another thread someone was suggesting sup720 3CXL for a similar scenario (but I don't remember if the providers were 5 or 3).
Hope to help