On 2012-12-13, at 9:56 AM, Phil Mayers <[email protected]> wrote:
> On 13/12/12 14:47, Jason Lixfeld wrote: >>> >>> Yes. In fact, that's *required* if you want to do multi-path. >> >> I seem to do multi-path just fine with maximum-paths ibgp 2 on my RR >> clients inside a VRF that sees a default sourced from two different >> RRs. Said VRF has a common RD between the two PEs. >> >> How is that different? > > Well, AIUI multipath *ought* to require unique RDs. Obviously not; I wonder > how that's working for you? So based on the link you posted previously, which I am currently making my way through, what's happening is on my production network where this multi-path stuff is actually working, I'm using XR as my RRs, which has add-path support. > Basically, as I'm sure you are aware, without "add paths" support, BGP can > only advertise one copy of a route - any "update" for a route implicitly > "withdraw"s a previous route. > > Therefore, if your RR sends: > > update nh=x.x.x.x nlri=65000:1:192.0.2.0/24 > update nh=y.y.y.y nlri=65000:1:192.0.2.0/24 > > ...then the 2nd update should wipe the first. This is why (in theory) > multipath requires a unique RD: > > update nh=x.x.x.x nlri=65000:1:192.0.2.0/24 > update nh=y.y.y.y nlri=65000:2:192.0.2.0/24 > > ...are different routes. > > Out of curiosity, what does: > > sh ip bgp vpnv4 vrf XXX net/mask > sh ip cef vrf XXX net/mask detail > > ...say for one of your working multipath prefixes? > _______________________________________________ > 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/
