nanog mailing list archives
Re: about interdomain multipath routing.
From: Matthew Petach <mpetach () netflight com>
Date: Tue, 10 Nov 2009 01:23:13 -0800
On Tue, Nov 10, 2009 at 1:10 AM, Doug Lane <laned1 () gmail com> wrote:
On Tue, Nov 10, 2009 at 3:50 AM, Matthew Petach <mpetach () 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
Current thread:
- about interdomain multipath routing. Bin Dai (Nov 09)
- Re: about interdomain multipath routing. Steven King (Nov 09)
- Re: about interdomain multipath routing. Matthew Petach (Nov 09)
- Re: about interdomain multipath routing. Jack Bates (Nov 09)
- Re: about interdomain multipath routing. Steven King (Nov 09)
- Re: about interdomain multipath routing. Doug Lane (Nov 10)
- Re: about interdomain multipath routing. Matthew Petach (Nov 10)
- Re: about interdomain multipath routing. Steven King (Nov 10)
- Re: about interdomain multipath routing. Jack Bates (Nov 09)
- Re: about interdomain multipath routing. Kevin Loch (Nov 09)