yep that one can't hurt On Wed, Dec 2, 2015 at 9:22 AM, Donald Sharp <[email protected]> wrote:
> Paul - > > I believe that this patch should fix your issue: > > > https://github.com/CumulusNetworks/quagga/commit/f4eeff72d5be6c1065f11face168a4bcd832de78 > > From my notes it should apply cleanly to master. > > donald > > On Wed, Dec 2, 2015 at 5:11 AM, Paul Jakma <[email protected]> wrote: > >> Is it just me, or does the mpath code do strange stuff, at least under >> asp-ath relaxed? E.g. if I run a set of bgpds in a ring, with each >> connected to the previous and next 2 bgpd instances in the ring (using a >> tweaked version of tools/multiple-bgpd.sh), current master without mpath >> gives: >> >> # sh ip bg 10.7.0.0/24 >> BGP routing table entry for 10.7.0.0/24 >> Paths: (4 available, best #4, table Default-IP-Routing-Table) >> Advertised to non peer-group peers: >> 192.168.145.2 192.168.145.3 192.168.145.5 >> 64563 64561 64567 >> 192.168.145.3 from 192.168.145.3 (192.168.145.3) >> Origin IGP, localpref 100, valid, external >> Community: 64563:1 >> Extended Community: RT:64561:1 RT:64563:1 RT:64567:1 SoO:64561:2 >> SoO:64563:2 SoO:64567:2 >> Last update: Wed Dec 2 09:47:14 2015 >> >> 64562 64568 64567 >> 192.168.145.2 from 192.168.145.2 (192.168.145.2) >> Origin IGP, localpref 100, valid, external >> Community: 64562:1 >> Extended Community: RT:64562:1 RT:64567:1 RT:64568:1 SoO:64562:2 >> SoO:64567:2 SoO:64568:2 >> Last update: Wed Dec 2 09:46:45 2015 >> >> 64565 64567 >> 192.168.145.5 from 192.168.145.5 (192.168.145.5) >> Origin IGP, localpref 100, valid, external >> Community: 64565:1 >> Extended Community: RT:64565:1 RT:64567:1 SoO:64565:2 SoO:64567:2 >> Last update: Wed Dec 2 09:46:44 2015 >> >> 64566 64567 >> 192.168.145.6 from 192.168.145.6 (192.168.145.6) >> Origin IGP, localpref 100, valid, external, best >> Community: 64566:1 >> Extended Community: RT:64566:1 RT:64567:1 SoO:64566:2 SoO:64567:2 >> Last update: Wed Dec 2 09:46:15 2015 >> >> The ASNs are 64560+x and each advertises 10.x.0.0/24 (amongst other >> things). There are 8 in total in the ring, and the above is x == 4 / >> AS64564. So the peerings are: >> >> peers x peers >> 7 8 1 2 3 >> 8 1 2 3 4 >> 1 2 3 4 5 >> 2 3 4 5 6 >> 3 4 5 6 7 >> 4 5 6 7 8 >> 5 6 7 8 1 >> 6 7 8 1 2 >> >> >> 4 has paths 453, 423 and 43 to 3; and paths 457, 467, 4287 and 4317 to 7. >> >> Look what happens if I set: >> >> maximum-paths 32 >> bgp bestpath as-path multipath-relax >> >> on all the bgpds. This is the view from 4: >> >> # sh ip bg 10.7.0.0/24 >> BGP routing table entry for 10.7.0.0/24 >> Paths: (4 available, best #4, table Default-IP-Routing-Table) >> Advertised to non peer-group peers: >> 192.168.145.2 192.168.145.3 192.168.145.6 >> 64563 {64561,64562,64565,64567,64568} >> 192.168.145.3 from 192.168.145.3 (192.168.145.3) >> Origin IGP, localpref 100, valid, external, multipath >> Community: 64563:1 >> Extended Community: RT:64561:1 RT:64562:1 RT:64563:1 RT:64565:1 >> RT:64567:1 RT:64568:1 SoO:64561:2 SoO:64562:2 SoO:64563:2 SoO:64565:2 >> SoO:64567:2 SoO:64568:2 >> Last update: Wed Dec 2 09:55:33 2015 >> >> 64562 {64561,64567,64568} >> 192.168.145.2 from 192.168.145.2 (192.168.145.2) >> Origin IGP, localpref 100, valid, external, multipath >> Community: 64562:1 >> Extended Community: RT:64561:1 RT:64562:1 RT:64567:1 RT:64568:1 >> SoO:64561:2 SoO:64562:2 SoO:64567:2 SoO:64568:2 >> Last update: Wed Dec 2 09:55:32 2015 >> >> 64566 64567 >> 192.168.145.6 from 192.168.145.6 (192.168.145.6) >> Origin IGP, localpref 100, valid, external, multipath >> Community: 64566:1 >> Extended Community: RT:64566:1 RT:64567:1 SoO:64566:2 SoO:64567:2 >> Last update: Wed Dec 2 09:53:32 2015 >> >> 64565 64567 >> 192.168.145.5 from 192.168.145.5 (192.168.145.5) >> Origin IGP, localpref 100, valid, external, multipath, best >> Community: 64565:1 >> Extended Community: RT:64565:1 RT:64567:1 SoO:64565:2 SoO:64567:2 >> Last update: Wed Dec 2 09:53:03 2015 >> >> That looks like it's multipathing over /all/ the paths to 7, including >> the longer 3-hop paths. Also, the aggregates don't really make sense, do >> they? >> >> It is advertising this aggregate back to the neighbours from whose routes >> the aggregate was constructed: >> >> # sh ip bgp neighbors 192.168.145.2 advertised-routes *> 10.7.0.0/24 >> 192.168.145.4 0 >> {64561,64562,64563,64565,64566,64567,64568} i >> # sh ip bgp neighbors 192.168.145.3 advertised-routes >> *> 10.7.0.0/24 192.168.145.4 0 >> {64561,64562,64563,64565,64566,64567,64568} i >> # sh ip bgp neighbors 192.168.145.5 advertised-routes >> # sh ip bgp neighbors 192.168.145.6 advertised-routes >> *> 10.7.0.0/24 192.168.145.4 0 >> {64561,64562,64565,64566,64567,64568} i >> >> So, in terms of the advertised routes and deciding who to advertise a >> route onto, it is taking only the 'best' path via 6 into consideration. >> >> Does this make sense to anyone? It seems seriously borken to me... >> >> Also, the mpath code probably should have been implemented using the >> existing aggregation code... >> >> regards, >> -- >> Paul Jakma [email protected] @pjakma Key ID: 64A2FF6A >> Fortune: >> I have discovered the art of deceiving diplomats. I tell them the truth >> and they never believe me. >> -- Camillo Di Cavour >> >> _______________________________________________ >> Quagga-dev mailing list >> [email protected] >> https://lists.quagga.net/mailman/listinfo/quagga-dev >> > > > _______________________________________________ > Quagga-dev mailing list > [email protected] > https://lists.quagga.net/mailman/listinfo/quagga-dev >
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