VRRP
Virtual Router
Redundancy Protocol. VRRP specifies an election protocol that dynamically assigns
responsibility for a virtual router to one of the VRRP routers on a LAN. The VRRP router
controlling the IP address(es) associated with a virtual router is called the master router,
and forwards packets sent to these IP addresses. The election process provides dynamic
failover in the forwarding responsibility should the master router become unavailable. In
case the master router fails, the virtual IP address is mapped to a backup router's IP
address; this backup becomes the master router. This allows any of the virtual router IP
addresses on the LAN to be used as the default first-hop router by end-hosts. The advantage
gained from using VRRP is a higher availability default path without requiring configuration
of dynamic routing or router discovery protocols on every host. VRRP is defined in RFC
2338.