----- Original Message ----- From: "Henning Brauer" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Thursday, August 11, 2005 1:58 PM Subject: Re: bgpd and two CARPed routers
> * Hyb <[EMAIL PROTECTED]> [2005-08-11 14:18]: > > While I wouldn't consider my BGP knowledge as strong, it was fundamentally > > the CARP interaction that I was trying to grasp > > oh, that is very easy. > > you tell bgpd that a neighbor session depends on an interface. all it > does is too look at that interface's status - let's assume carp here, > that is what this is for really -, and as long as that interface is > BACKUP, the session is kept in state IDLE. the very same moment the > interface becomes MASTER it triggers a start event for the sessions in > question, which means they go to CONNECT or ACTIVE, dependending on > wether the question is configured passive or not. Thus (if not > configured passive) bgpd tries to establish the session immediately > when the carp interface becomes master. > > > For instance is it possible to achieve an equivalent of Cisco's > > 'non-exist-map' statement? > > dunno what this does ;) It's allows you produce conditional advertisements, based upon what it sees in the routing table. For instance allowing an additional prefix to be advertised in the event that a secondary site fails and stops advertising it. I guess the same could be acheived by prepend, just not as nicely. > hope it's clear now Thanks, much clearer! I just have one remaining query - with two sessions from each upstream and CARP on the inside interface, does this make a legitimate scenario for ifstated? Presumably if both upstream interfaces failed on the CARP master, but the internal interface remained functional, then the internal network would loose connectivity. Thanks,
