This is entirely multicast. We used the s-g-hash to lock each S,G to a link, but we didn't think it through. We really should have started out using the next-hop-based hash so that the same S,G can be served by any link in the group. With s-g-hash, it always gets locked to the same bundle.
However, I just thought of another potential culprit. I'm going to have to think it through, though. On Sat, Oct 2, 2010 at 10:17 PM, Keegan Holley <[email protected]> wrote: > I've seen similar effects. I'm not sure there's a method to evenly > distribute traffic for an indefinite period. I'm also not sure what you're > routing, but the problems I've seen are usually caused by the fact that each > flow/hash result differs in size and duration. Adding extra variables to > the equation always helps, but it's almost impossible to keep an even > spread. I suppose your current goal is to simply stop the outages though. > > > On Sat, Oct 2, 2010 at 7:17 PM, John Neiberger <[email protected]> wrote: >> >> I hate to answer my own question, but I think I figured it out. We're >> using s-g-hash basic, which is prone to polarization. I think that's >> what we're seeing. Our traffic has become polarized and has developed >> an affinity for a subset of links in our "bundles". I'm recommending >> that we switch to s-g-hash next-hop-based to see if that resolves the >> problem. >> >> On Sat, Oct 2, 2010 at 2:18 PM, John Neiberger <[email protected]> >> wrote: >> > We converted several connections last week from Etherchannels to >> > routed links with ECMP. We verified that traffic was load-sharing over >> > those links after making the change. Now, a week later, we are seeing >> > instances where traffic is preferring one or two links out of each >> > "bundle". In some cases all the traffic is flowing over a single link >> > in a four-link setup. This is overloading those connections and we >> > can't figure out why. We are using s-g-hash basic. Should we switch to >> > s-g-hash next-hop-based? >> > >> > This is causing production issues right now, so I've opened up a TAC >> > case, but I thought I'd ask here, as well, just in case someone had >> > seen this before. >> > >> > Thanks, >> > John >> > >> _______________________________________________ >> cisco-nsp mailing list [email protected] >> https://puck.nether.net/mailman/listinfo/cisco-nsp >> archive at http://puck.nether.net/pipermail/cisco-nsp/ >> >> > > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
