On 7. mars 2010, at 00.07, Claudio Jeker wrote: > On Sat, Mar 06, 2010 at 06:52:24PM +0100, Rogier Krieger wrote: >> On Sat, Mar 6, 2010 at 17:26, PP;Q Q P(P8P?P8QP8P= > <chipits...@gmail.com> >> wrote: >>> no, I want routes exactly to carp. >> >> That sounds odd. Routes are something different than what particular >> host responds to frames directed to a specific hardware address. >> >> If I understand the rest of your description correctly, you want only >> the master bgpd to have sessions and to somehow distribute its routes >> to the backup(s), with the backups starting with that 'state' and >> initiate connections to your BGP peers whenever a master goes down. I >> doubt that'll work. >> >> In your scenario, if your master goes down, there are no longer any >> BGP sessions up with any of your peers. If I'm not mistaken, that will >> cause them to withdraw the prefixes you previously advertised from >> their tables and no longer forward traffic to you. >> > > Right, as soon as the master dies the routes will be withdrawn (there may > be some overlap since it is possible that carp switches before bgpd > realizes the loss). At the moment it is not possible to have a real backup > router running. I have some ideas and partial diffs that will allow backup > CARP nodes to preload tables. Main problem is that we need graceful > restart for this but most peers (as in cizzzcoee) are not able to assist > graceful restart. > > Btw. I'm looking for a device that is capable of doing graceful restarts > (as for example some foundry) to test my diff against. Would be great if I > could get access to a lab router to play with. > >> When your new master is promoted, it will set up a new session with >> your peers. This is probably not the sort of failover you want to see >> happening in production. >> > > That's why you have multiple bgpd routers with redundant pathes. > > -- > :wq Claudio >
Not 100% sure what you mean by "...are not able to assist...", but IOS supports BGP graceful restart as per RFC4724. e.g.: http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ftbgpnsf.html #wp1049642 /Pete
