> the first thing that comes to mind is that OSPF is the only other routing > protocol where RID is an inherant part of the structure and the process. > > as to why this becomes an issue, since RIDs can change based upon > reconfigurations and reloads and process clearing, I can see the code > getting confused. add a loopback. clear the ospf process, the RID changes, > but does not change for BGP because the process is stable. or visa versa. > this is starting to tell me that maybe there is a RID routine in the IOS > code that both BGP and OSPF reference when starting up. > > write it off as "cronkite" because "that's the way it is"? not a bug, but a > feature? >
the 'feature' is a pretty tricky deal. what the sync 'feature' required is the RID for the OSPF route match the RID of the BGP route. John came up with the solution, and it worked. The redistribution point also plays a key role - when redistributing OSPF into BGP, it worked best when done at a BGP router that was sync'ed. The additional complication was a route reflector preventing the real full iBGP mesh. It is a show-stopper if you don't get that match and try to get unsynced iBGP routes advertised to an eBGP neighbor. My conclusion: The additional sync requirement of matching OSPF RIDs (instead of just the routing table) is a real pain in the butt. > Chuck > > > ""John Neiberger"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > We discovered something on the CCIE list recently and I'm > > wondering if anyone might be able to explain the reasoning > > behing this behavior. > > > > BGP synchronization rules require that if an iBGP peer is to > > advertise a route learned via iBGP, it must have that prefix > > *and* the next hop for that route in the routing table already. > > > > An interesting added complexity to this occurs if your IGP is > > OSPF. If the router in question has learned these prefixes via > > OSPF, then the advertising router ID in the OSPF database must > > match the router ID of the iBGP peer that advertised the route. > > > > Has this behavior caused any problems for any of you? Do you > > know why the synchronization rules have a special case for OSPF > > and not other routing protocols? > > > > I was working with someone else on a practice lab and we ran > > into this issue. We were both going nuts trying to figure out > > why the iBGP routes weren't synchronizing and this turned out > > to be the cause. > > > > Any thoughts? > > > > Thanks, > > John > > > > ________________________________________________ > > Get your own "800" number > > Voicemail, fax, email, and a lot more > > http://www.ureach.com/reg/tag _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=30282&t=30126 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
