Ahhhhh, yes, don't confuse the VRRP protocol itself (the communication between the VRRP participant routers) and the VIP/VMAC that clients use to talk to the VRRP Virtual Router!
Since the VRRP protocol is exchanged across the multicast address 224.0.0.18, that *would* use a true multicast MAC address. On Sat, Oct 20, 2012 at 4:31 PM, Mark Beynon <[email protected]> wrote: > Sorry guys, I spotted my mistake! Thanks for helping me see clearly Bob! > Couldn't see the wood for the google! > > Vrrp packets ARE sent to the multicast Ip and MAC, but sourced from > 0000.5e ... Etc.. > > Sorry > On Oct 20, 2012 9:20 PM, "Bob McCouch" <[email protected]> wrote: > >> Because the RFC says so: http://tools.ietf.org/html/rfc3768#section-7.3 >> >> :-) >> >> Actually I'd say it's because it's not *really* a multicast MAC address. >> It's closer to an Anycast address in concept. Intentional collision in >> order to provide a redundant service. And Anycast addresses (to continue >> the metaphor) are actually unicast addresses, not multicast ones. >> >> Among other things, Cisco switches get rather upset at the idea of >> binding a unicast IP address to a multicast MAC address (in that, they >> won't do it -- it's one reason Microsoft NLB is such a pain). Perhaps the >> protocol designers decided to make sure such conflicts weren't a problem. >> >> >> >> On Sat, Oct 20, 2012 at 4:13 PM, Mark Beynon <[email protected]>wrote: >> >>> Hopefully a simple question, but I can't find the answer and i'm hoping >>> the >>> wider collective can... >>> >>> Multicast IP addresses derive multicast MAC addresses, which start >>> 0100.5e. >>> >>> So why is the vrrp MAC 0000.5e00.01xx?? (not 0100.5e etc) >>> >>> ? >>> >>> Thanks >>> _______________________________________________ >>> For more information regarding industry leading CCIE Lab training, >>> please visit www.ipexpert.com >>> >>> Are you a CCNP or CCIE and looking for a job? Check out >>> www.PlatinumPlacement.com >>> >>> http://onlinestudylist.com/mailman/listinfo/ccie_rs >>> >> >> _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
