Hello, I'm no BGP guru but I can put in my guess on the "motivation" part: Cost :) Atleast that was something we considered when planning our multi-homing solution @work and not being completely fluent in BGP yet :)
Consider the following setup: 2 routers, 2 peerings: 1 peering to router 1 and 1 peering to router 2, igp between router 1 and router 2. Getting two BGP-sessions to each transit to have a full mesh will in most cases double the cost for that transit capacity, so instead of having 2 * X Mbps costs you would have 4 * X Mbps costs. By configuring the BGP to a VIP on the routers one would think that there is another layer of resilency for hardware failure in the VRRP instead of just relying on BGP timers / BFD to fail over traffic to the other BGP session...but like Pekka said, I'm not sure about the motivation and real facts here... :) What would be the major drawbacks/differences between using 2 peerings, 4 peerings fully meshed and 2 peerings to router VIPs in the above scenario? Regards, Kim Halavakoski On 28 Mar 2008, at 18:30, Pekka Savola wrote: > On Fri, 28 Mar 2008, Stefan Fouant wrote: >> There is some internal debate here in my office today as to whether >> or not >> Juniper can support a BGP implementation in conjunction with VRRP, >> as in, >> BGP is sourced from a VRRP VIP address. >> >> Now before everyone attempts to tear me a new one... I should >> state that >> I'm pretty sure this shouldn't be done and to do so would pretty >> much break >> the protocol in every way imaginable... however, I am being told >> that Cisco >> has some knobs to accomplish this and I just want to be certain if >> Juniper >> can do something along these lines... > > I guess this would work, for some definition of "work", if you add > "accept-data" under VRRP config. > > The BGP session would flap when VRRP mastership switches (TCP reset, > so it would likely be re-established quickly), but depending on the > number of routes carried and some other BGP timers, this would be > possible. > > I'm not sure what motivation there would be to configure BGP to VIP > address, instead of just having two BGP sessions and tuning down BGP > timers (and/or using BFD). > > -- > Pekka Savola "You each name yourselves king, yet the > Netcore Oy kingdom bleeds." > Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings > _______________________________________________ > juniper-nsp mailing list juniper-nsp@puck.nether.net > https://puck.nether.net/mailman/listinfo/juniper-nsp _______________________________________________ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
