----- Original Message ----- From: "Kent Yu" To: Sent: Tuesday, February 05, 2002 8:30 PM Subject: Re: Undocumented iBGP Behavior (Confirmed by Cisco) [7:34548]
> Alan, > > TAC engineer actually told you this is a new feature? Did you ask him since > when? As I mentioned in another post, my co-worker was the one actually doing the talking. He didn't say it was a feature, but rather "a change in the behavior." To me, a new feature means that I can type in a command, and gain some kind of advantage... This happens all by itself. > BGP only tells its peers the best route it selects, this is not a new > feature, AFAIK. Right... Only routes that actually get selected and installed on a router are eligible to be advertised to other BGP peers (Be they iBGP, or eBGP). That has not changed. > If you consider your AS as one unit, it should look like this: > > For the routes that your AS prefers AS1, in your router connects to AS1, > you will only see one ebgp path for this route, as this is the best path > this router is using, it will tell its ibgp peers which is the router links > to AS701. On the 701 router, you will see two bgp paths with the ibgp path > being preferred, but there is no point for this router to advertise its ebgp > path for this route to the first router, because the ebgp path is not the > best path. All I can tell you is that it always has in the past... That route should sit there, ignored, in the Adj-RIB-in (you should see it in the output of 'sh ip bgp'). That table contains _all_ of the learned paths to a spefic network/prefix, not just the _best_ path. The best path is marked with ">", and is the one that gets installed into the router's routing table, provided the router meets syncrhonization and next-hop-reachability restrictions (which are normally addressed with "no synchronization" and "next-hop-self"). Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=34572&t=34548 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
