Configuring VRRP policies and configuring VRRP instances on interfaces and router interfaces is optional. The basic owner and non-owner VRRP configurations on an IES or router interface must specify the backup ip-address parameter.
VRRP helps eliminate the single point of failure in a routed environment by using a virtual router IP address shared between two or more routers connecting the common domain. VRRP provides dynamic failover of the forwarding responsibility if the master becomes unavailable.
The VRRP implementation allows one master per IP subnet. All other VRRP instances in the same domain must be in backup mode.