Technology: Routing
Area: NHRP
Vendor: Cisco
Software: 12.X , 15.X
Platform: Catalyst platforms, Routing platforms

The Virtual Router Redundancy Protocol (VRRP) is an election protocol that dynamically assigns responsibility for one or more virtual routers to the VRRP routers on a LAN, allowing several routers on a multiaccess link to utilize the same virtual IP address. In a VRRP configuration, one router is elected as the virtual router master, with the other routers acting as backups in case the virtual router master fails. VRRP is designed for use over multiaccess, multicast, or broadcast capable Ethernet LANs

To enable VRRP (basic config), use the following command on router 1:

Router1(config)# interface GigabitEthernet  0/1
Router1(config-if)#ip address 20.1.1.2 255.255.255.0
Router1(config-if)# vrrp 10 priority 120
Router1(config-if)# vrrp 10 ip 20.1.1.1

configure also router 2 as a backup NHRP router:

Router2(config)# interface GigabitEthernet  0/1
Router2(config-if)#ip address 20.1.1.3 255.255.255.0
Router2(config-if)# vrrp 10 priority 100
Router2(config-if)# vrrp 10 ip 20.1.1.1