Definition
Virtual Router Redundancy Protocol (VRRP)
Virtual Router Redundancy Protocol (VRRP) is a layer 3 redundancy protocol used in networks to ensure the availability of a default gateway.
It is the open equivalent of the Cisco-proprietary Hot Standby Router Protocol.
Routers
Master Router
The router with the highest priority becomes the master router, responsible for forwarding traffic (similar to HSRP’s Active Router). Instead of using Hello messages (HSRP), VRRP uses Advertisement messages to announce their priority or state.
If the priorities are the same, the router with the higher IP address wins the election.
Backup Router
If the Backup Routers does not receive an Advertisement message from the Master within a predefined period, known as the Master Down Interval, one of the Backup routers with the highest priority will take over as the Master.