> Is this per-packet, or per-flow load balancing? The command allows FIB to receive and install multiple ECMP prefixes from BGP RIB. The actual load-balancing algorithm is independent from this process, so standard per interface "ip load-sharing" config should apply.
> How much memory usage would it increase assuming 2-3 full tables in memory > already (around 400Mb usage, 1Gb RAM)? Looks like you've got 2 defaults only. I need to lab this up to be absolutely certain, but the BGP RIB memory consumption shouldn't change at all. FIB/CEF memory consumption is likely to double (in my case I would expect it to go from 49MB to something close to 100MB). HTH, Andrew On 18/05/2010, at 11:58 PM, Randy McAnally wrote: > I can find very little info on 'bgp bestpath as-path multipath-relax' > > Is this per-packet, or per-flow load balancing? > > How much memory usage would it increase assuming 2-3 full tables in memory > already (around 400Mb usage, 1Gb RAM)? Looks like you've got 2 defaults only. > > -- > Randy > > ---------- Original Message ----------- > From: Andrew Tolstykh <[email protected]> > To: amps <[email protected]> > Cc: [email protected] > Sent: Tue, 18 May 2010 16:29:52 +1000 > Subject: Re: [c-nsp] BGP load balancing (outbound) > >> ECMP load balancing works with the hidden "bgp bestpath as-path >> multipath-relax" command applied (thanks Anton!) >> >> router bgp XXX >> maximum-paths 2 >> bgp bestpath as-path multipath-relax >> >> sh ip route bgp >> B* 0.0.0.0/0 [20/0] via 13.13.13.3, 00:05:59 >> [20/0] via 12.12.12.2, 00:05:59 >> >> sho ip cef 0.0.0.0 0.0.0.0 >> 0.0.0.0/0 >> nexthop 12.12.12.2 FastEthernet1/0 >> nexthop 13.13.13.3 FastEthernet1/1 >> >> If you are after the per-AS load-sharing configuration, then you >> should probably flip route-map TRANSIT-1-INT permit 10 and 20 statements. >> Also don't forget to add blank "route-map TRANSIT-2-IN permit 20" statement. >> >> route-map TRANSIT-1-IN permit 10 >> match as-path 105 >> set local-preference 210 >> route-map TRANSIT-1-IN permit 20 >> >> route-map TRANSIT-2-IN permit 10 >> match as-path 106 >> set local-preference 210 >> route-map TRANSIT-2-IN permit 20 >> >> HTH, >> Andrew >> >> On 18/05/2010, at 2:42 AM, amps wrote: >> >>> Let's say I wanted to send traffic to even AS's out peer 1 and odd AS's > out peer 2. >>> >>> Am I crazy? (Seems better than using metrics based solely on static IP > ranges...) >>> >>> Would this work? >>> >>> route-map TRANSIT-1-IN permit 10 >>> set as-path prepend last-as 1 >>> ! >>> route-map TRANSIT-1-IN permit 20 >>> match as-path 105 >>> set local-preference 210 >>> ! >>> >>> route-map TRANSIT-2-OUT permit 10 >>> set as-path prepend xxxxx >>> ! >>> >>> route-map TRANSIT-2-IN permit 10 >>> match as-path 106 >>> set local-preference 210 >>> ! >>> >>> route-map TRANSIT-2-OUT permit 10 >>> ! >>> >>> ip as-path access-list 105 permit [02468]$ >>> >>> ip as-path access-list 106 permit [13579]$ >>> >>> >>> On Mon, May 17, 2010 at 10:59 AM, Anton Kapela <[email protected]> wrote: >>> On Mon, May 17, 2010 at 10:42 AM, Andrew Tolstykh <[email protected]> wrote: >>>> Just a shot in the dark, but I don't see load balancing enabled in your > configuration snippet: >>>> >>>> router bgp xxxxx >>> >>> This question comes up semi-often, perhaps there ought to be a FAQ? (I >>> may have missed it). >>> >>> For different-upstream AS's, ecmp will not normally occur. You'll need >>> to adjust the bgp bestpath determination functions, else the different >>> next-AS's will prevent ECMP forwarding from being pushed to the FIB. >>> >>> http://puck.nether.net/pipermail/cisco-nsp/2005-November/025993.html >>> >>> -Tk >>> >> >> _______________________________________________ >> cisco-nsp mailing list [email protected] >> https://puck.nether.net/mailman/listinfo/cisco-nsp >> archive at http://puck.nether.net/pipermail/cisco-nsp/ > ------- End of Original Message ------- > > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
