Virtual router redundancy protocol (VRR) is a computer network protocol that allows the automatic allocation of existing Internet Protocol (IP) routers to participating hosts. This increases the availability and reliability of routing routes through automatic selection of the default gateway in an IP subnet.
This protocol acts as a group by creating virtual routers, which are an abstract representation of multiple routers, i.e. primary/active and secondary/standby routers. The virtual router is assigned as a default gateway of participating hosts instead of the physical router. If the physical router that routs packages from the virtual router fails, another physical router is selected to be replaced automatically. The physical router that sends packages at any given time is called the primary/active router.