* Alex Bligh > We would be interested in a sane implementation of VRRP. We'd also > be even more interested in other interfaces redundancy protocols that > do not "waste" IP addresses (e.g. do not use IP addresses for the > native interfaces). One problem with VRRP is that it is allegedly > patent encumbered.
FWIW, Keepalived's VRRP implementation has a feature which allows it to 1) specify any arbitrary source address in the VRRP hellos, e.g. the loopback interface's, and 2) define the virtual address with a netmask. This probably breaks RFC compliance and interoperability with other implementations, but it does allow you to run VRRP on unnumbered interfaces, thus not wasting any IP addresses. One caveat is that you need to disable uRPF, another one is that the VRRP-speaking routers will be active/passive for egress traffic to the LAN, since the passive one(s) won't have an interface route to the network served. In any case, an VRRP implementation in BIRD could easily implement the same trick. Also, I believe it is HSRP that's patent encumbered, not VRRP. -- Tore Anderson Redpill Linpro AS - http://www.redpill-linpro.com Tel: +47 21 54 41 27
