Firstly, in classical BGP implementations (but not in BIRD), for eBGP connections, router-id is never used as tie-break. Instead, route age is used (the oldest one wins) as tie-break. It avoids frequent route changes and probably improves a little routes distribution. You'd better use "prefer older on".
Secondly, a radical solution is (for incoming prefixes): - upstream 1: match net ~ 0.0.0.0/1 and set MED at 1, set MED at 0 for everything else; - upstream 2: match net ~ 128.0.0.0/1 and set MED at 1, set MED at 0 for everything else. You can leave that config once for all, or remove it a few minutes later if "prefer older on" is configured. regards, Olivier > Le 3 nov. 2014 à 14:44, Tigran Zakoyan <[email protected]> a écrit : > > Dear colleagues, > > My issue is best route selection in BGP protocol. > > I have two uplinks providing full view to me. The world connectivity > of the First one is slightly better, than the Second's. But I get in > result 90% of routes selected through the First. > > There are no LP or MED differences. And most, if not all, of the > routes with the same AS path length get chosen from the First's table. > > I presume it to be the influence of lower router ID (77.x.x.x the > First and 210.x.x.x the Second). > If it's the case, is there any way to deviate the BIRD's decision? To > make it choose more routes from the Second's? > > Thanks and cheers, > Tigran Zakoyan.
