Hi, By default the MED comparison only occurs in the first (the neighboring) AS is the same in the two paths -which is not your case
Since these are eBGP routes the next tie breaker is: Prefer the path that was received first (the oldest one) IOS always displays the routes the way that the oldest one is at the bottom and the newest one is at the top of the "show ip bgp" output So in your example the bottom one selected as the best is indeed the oldest one I have this one printed out and always handy: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094431.shtml adam -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Nikolay Shopik Sent: Tuesday, October 11, 2011 11:18 AM To: cisco-nsp Subject: [c-nsp] bgp bestpath w/o bgp always-compare-med Hi, I have rather strange best path selection. We have 3 uplinks, AS_PATH to one of prefix is same for all 3 prefixes, so my assumption it will use oldest one, because everything else is same. Except one thing I notice one of uplinks send us metric, while two others does not. Here is example, first one is oldest, second is youngest, but it still choices last one. While should choice first, because everything else is same. 39792 9002 25532 Origin IGP, metric 400, localpref 100, valid, external Community: 39792:3000 39792:3004 41095 9002 25532 Origin IGP, localpref 100, valid, external Community: 41095:2000 41095:2001 41095:2100 41095:2101 30733 9002 25532 Origin IGP, localpref 100, valid, external, best Community: 9002:0 9002:64667 30733:6022 I start to believe it using metric anyway, while I don't use that option. What I missing here? _______________________________________________ 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/
