I gather this will adversely effect all those who want to "load balance across the internet" ;->
Chuck ""W. Alan Robertson"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > ----- Original Message ----- > From: "Ouellette, Tim" > > > > The 2nd router that only has 700 routes in it's routing > > table that it learned from it's IBGP still has the other > > 103k routes in it's adj-rib-in from it's ebgp peer right, > > they are just sitting dormant? So if the other router > > somehow lost it's ebgp peer, it'll send withdraws to the > > ibgp peer and the other guy will take over with 104k > > routes correct? > > Exactly... > > > Could you define what you meant buy "if an iBGP peer > > learns that another iBGP peer already has a better route > > to a specific prefix, it will issue a withdrawl to that > > peer for the prefix(es)." > > Let me see if I can articulate that a little better... > > > [ eBGP ] [ eBGP ] > [AS 701] [ AS 1 ] > | | > 104k| |104K > | | > | | > [ BGP ] [ BGP ] > [AS "X"] [AS "X"] > | | > | > > My router that connects to AS 1 has learned roughly 104k prefixes via > eBGP... > > My router that connects to AS 701 has also learned roughly 104k > prefixes via eBGP... > > Via iBGP, the AS1 connected router tells my other router of the 104k > prefixes that it has learned... > > At the same time, my AS701 connected router is transmitting the 104k > prefixes it has learned to the AS1 connected router... > > Once each of my routers has finished their mutual exchange of routes, > the AS701 connected router sees that for all but approximately 700 > prefixes, the AS1 connected router has an equally good path, and via > the iBGP connection, he issues withdraws for 103.3k of the routes that > he had previously announced to my other router... > > At this point, each of the routers has a full table learned via eBGP, > and 'show ip route' yields about 4 gazillion pages of output... > > A 'show ip bgp' also yields a ton of output, but the AS701 connected > router shows two entries for each prefix (One learned via the external > peer, and one learned via the internal peer), but the AS1 connected > router has a single entry per prefix. > > > > If both of those routers are receiving full routes, and > > without any other configuration, how would the routes > > learned from one provider be any better than the other? > > With no additional configuration, "customer" routes (those that > originate in a directly connected external AS, or are a single hop > away, if single homed) would be fewer AS hops away... They would be > preferred... > > > Thanks and great post! > > Thank you... > ;) Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=34553&t=34550 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
