If there's a need for R1 and R2 to exchange equal number of prefixes than just enable "bgp advertise-best-external" on both routers
adam -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Chuck Church Sent: Sunday, December 09, 2012 11:28 PM To: 'Gert Doering' Cc: [email protected] Subject: Re: [c-nsp] BGP sanity check Thanks. I guess in my mind the numbers needed to add up more. Both routers are taking a full table, which is more or less the same prefixes with different path information. R2 claims it's sending about 412K to R1, yet R1 only sends 100K to R2. I would think the number should add up approximately close to the full table size. This is significantly over that 430K number. Would the fact that each router may get the same path length for a prefix explain why some obviously are sent by each towards the other? Chuck -----Original Message----- From: Gert Doering [mailto:[email protected]] Sent: Sunday, December 09, 2012 4:47 PM To: Chuck Church Cc: [email protected] Subject: Re: [c-nsp] BGP sanity check Hi, On Sun, Dec 09, 2012 at 10:37:37AM -0500, Chuck Church wrote: > I'm thinking this might be because RTR 2's eBGP has the better path to > most destinations compared to RTR 1, thus RTR 1 sees this and doesn't > send those prefixes back towards RTR 2. Does that sound right? Exactly so. > Here's a prefix in question: > RTR 2: > BGP routing table entry for 209.209.144.0/20, version 3845458 > Paths: (1 available, best #1, table default) > Advertised to update-groups: > 9 > 20115 1299 4323 10397, (received & used) > 68.115.217.2 from 68.115.217.2 (96.34.212.228) > Origin IGP, localpref 100, valid, external, best > > RTR 1: > BGP routing table entry for 209.209.144.0/20, version 23114388 > Paths: (2 available, best #1, table Default-IP-Routing-Table) > Not advertised to any peer > <------------------------------------- This tells me it's not sent, > trying to figure out why Because the only peer he could send it to is RTR 2, and that's where the best path is learned from -> paths are never sent back to origin (and only best path is ever announced to peers). gert -- USENET is *not* the non-clickable part of WWW! //www.muc.de/~gert/ Gert Doering - Munich, Germany [email protected] fax: +49-89-35655025 [email protected] _______________________________________________ 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/
