On Tue, Nov 10, 2009 at 1:10 AM, Doug Lane <lan...@gmail.com> wrote: > On Tue, Nov 10, 2009 at 3:50 AM, Matthew Petach <mpet...@netflight.com> wrote: >> I've outlawed the use of multihop eBGP for load-sharing here; when we get >> multiple links off the same router to a peer or upstream, they are configured >> with multipath. We've got hundreds of BGP sessions across the network >> configured with multipath on them. >> > > Do you use iBGP multipath as well to load-balance between links on > different routers?
Yes. > I know eBGP multipath is fairly common, but I wonder how many are > using iBGP multipath as well. I doubt any carriers would support it, > so it's probably only useful for load-balancing outbound traffic. The > problem with eBGP multipath alone is that you might want to terminate > circuits from a given carrier on two different routers for redundancy > reasons, but that precludes any load-balancing with eBGP multipath. > Obviously your network has to be designed with equal-cost paths for > iBGP multipath to be of any value. > > -Doug iBGP with multipath, multiple LSPs to each BGP next-hop...much load balancing across all same-cost internal links to each of the eBGP multihop next-hops. inet.0: 300787 destinations, 2675963 routes (300092 active, 2 holddown, 2086 hidden) Yes...takes up a chunk more memory keeping track of all the different paths, but it does provide more end-to-end load balancing of traffic even on different routers. Matt
