VRRP Master Election

After the virtual router instance has been created, assign the IP addresses associated with this virtual router using the vrrp address command in interface configuration command mode, specifying the IP address and the VRID this address is to be associated with. A virtual router IP address can be either an address configured on the routing interface or an address that falls within the range of any networks configured on this routing interface.

If the virtual router IP address is the same as the routing interface (VLAN) address owned by a VRRP router, then the router owning the address becomes the master. The master sends an advertisement to all other VRRP routers declaring its status and assumes responsibility for forwarding packets associated with its VRID.

If the virtual router IP address is not owned by any of the VRRP routers, then the routers compare their priorities and the higher priority owner becomes the master. VRRP router priority is set using the vrrp priority command in interface configuration command mode. If priority values are the same, then the VRRP router with the highest IP address is selected master.

VRRP advertisements are sent by the master router to other routers participating in the VRRP master selection process, informing them of its configured values. Once the master is selected, then advertisements are sent every advertising interval to let other VRRP routers in this VRID know the router is still acting as master of the VRID. All routers with the same VRID should be configured with the same advertisement interval. Use the vrrp advertise-interval, in interface configuration command mode, to change the advertise-interval for this VRID.