VRRPv3 is a combined protocol for both IPv4 and IPv6. It specifies an election protocol that dynamically assigns responsibility for a virtual router to one of the VRRP routers on a LAN. The VRRP router that controls the IPv4 or IPv6 addresses associated with a virtual router is called the Master, and it forwards packets sent to these IPv4 or IPv6 addresses. VRRP Backups wait for a Master and take ownership when the Master is no longer detected.
The election protocol provides dynamic failover in the forwarding responsibility when the Master is unavailable. VRRP for IPv4 gains a higher-availability default path without configuring dynamic routing or router discovery protocols on every end-host. VRRP for IPv6 gains a quick switch-over to Backup routers compared to the standard IPv6 Neighbor Discovery mechanisms.
Note
The VRRP IPv6 link-local address must be the same for all VRRP routers sharing the same link and the same virtual router ID, that is, the same VRRP instance. It is the address the VRRP advertisements are sent from. Also, the Router Advertisement packets from the VRRP interface are transmitted using this address, so, when IPv6 Stateless Address Autoconfiguration is used, this address is added to host Default Router List and is used as a gateway.
The software supports VRRPv3 for IPv4 and VRRPv3 for IPv6. VRRPv3 for IPv6 is compliant to RFC 5798. The software also supports VRRPv2 for IPv4.