Hi, if its matter of egrees from router A. customers usually use local pref to select outgoing ISP.
Remember the AS_PATH comes after local preference in bgp path selection. They must be using route-map on neighbor command to change the default local preference of prefixes receiving from different ISPs.Higher local-pref will determine preferred outgoing path. However actual path selection can be determined by sh ib bgp prefix command as suggested by others. Thanks & Best Regards, Umair SaeedAM IP Operations Core South , Pakistan Telecommunication Company Ltd, Phone # +92 333 2354591 > From: [email protected] > To: [email protected] > Date: Tue, 31 Jan 2012 16:20:55 -0500 > CC: [email protected] > Subject: Re: [c-nsp] dumb BGP question > > Remember that pref is non transitive. > > If you could, could you do a show ip bgp prefix and paste the output? > > Then we might be able to expand more. > > Thanks > > On Jan 31, 2012, at 3:42 PM, John Brown wrote: > > > Hi, > > I'm suffering from driving spreadsheets instead of routers. > > > > Have a customer that has two routers. > > > > A and B > > > > A is connected to us > > B is connected to two other eBGP neighbors (transit providers) > > > > A and B are connected via iBGP. > > > > A == 7300 widget > > B === 9000 widget > > > > Traffic via our link is nearly 100 percent ingress to their router A. > > Very little egress from A. > > > > A is basically a router that feeds the link to us. > > > > B is their main "core" router. > > > > Looking at the routes in B, it shows that they are pref'n routes via B's > > transit providers, instead of via our link through A. > > > > Yet the AS path is much shorter via A to us. > > > > The same route via B is 5 AS's (no padded) and the route via A is 2 AS's > > > > In looking at the route selection priorities, Local-Pref and then AS path > > should cause our routes to win well before the iBGP / eBGP selection rule(S) > > > > Not sure what I'm missing here. I know its gotta be dumb and in another > > life I would know the answer. > > > > Thoughts oh wise list ?? > > > > Mucho thanks. > > > > > > _______________________________________________ > > 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/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
