Hi! On Jun 1, 2007, at 12:21 AM, Simon Leinen wrote:
> Arie Vayner \(avayner\) writes: >> Danny, >> With iBGP the timers for BGP are not really important... You >> actually need to worry about the IGP convergence. >> The reason for that is that usually when a link fails, you don't >> really expect the BGP session to the RR to go down, but just use the >> redundant IGP path. > > Yes, but what about when a router fails, in particular a border > (eBGP+iBGP) router? > > In such a case, iBGP timers (or the configuration of a mechanism such > as BFD) will determine how long it takes for other routers that the > eBGP routes from the dead router have to be dropped. This can be very > important, because using the dead router's eBGP routes can mean > blackholing traffic. No need to adjust the iBGP timers in that case. Your bgp-next-hop (which is ideally a loopback-ip of the crashed router) will simply disapear from your internal routing-table, and all iBGP neighbors (also the RRs) will remove all routes that are unreachable (because of the unreachable next-hop) from their tables. You only rely on the convergence-time of your igp (ospf? isis? ...?) to remove the "dead" loopback-ip from its table and the calculation of BGP that is triggered when the loopback-ip disappears. Stoffi -- CHRISTOPH LOIBL ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ mailto:[EMAIL PROTECTED] |No trees were killed in the creation of this message. http://pix.tix.at |However, many electrons were terrible inconvenienced. CL8-RIPE ++++++++++++++++++++++++++++++++++++ PGP-Key-ID: 0x4B2C0055 +++ _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
