The Virtual Router Redundancy Protocol (VRRP) is a standard first hop redundancy protocol that specifies an election protocol that dynamically assigns responsibility for a virtual router (VR) 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 and it forwards packets sent to these IP addresses. The election process provides dynamic failover in the forwarding responsibility, when the Master becomes unavailable. This will allow any virtual router (Master) IP addresses on the LAN to be used as the default gate for the hosts. The advantage of using VRRP is to provide a redundancy for the default gateways which used by endpoints.
In the VRRP, the Master router is responsible for forwarding the data packets received for VRRP MAC address. Backup routers listen for advertisement packets from the Master. In the case that Backup routers do not receive advertisement packets for a certain period of time from the Master, an election will start between backup routers to elect the new Master for VRRP interface.