vrrp preempt

Virtual Router Redundancy Protocol (VRRP) is very similar to HSRP and can create a virtual gateway but the difference that it is not the Cisco Proprietary Protocol.

It is a standard protocol defined by the IETF in RFC 3768. If you learn and understood HSRP then it is very easy for you to understand the Virtual Router Redundancy Protocol (VRRP).

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 and elects the role of the router.

Virtual Router Redundancy Protocol (VRRP) allows several routers on a multi-access link to utilize the same virtual IP address. In a VRRP configuration, one router is elected as the virtual router master and other routers acting as backups in case the virtual router master fails.

As in the previous two articles, Router2 and Router3 are neighbouring to the LAN segment. We will use the same topology for the Virtual Router Redundancy Protocol (VRRP) configuration. Router2 will be the master router and Router3 role is the backup router.

In the above topology, we are using two Cisco routers for VRRP. We have been tasked to configure VRRP. The IP addresses, routing and other pre-requisite have done. This is important to know that each device participating in the VRRP process also needs to be in the same broadcast domain and also requires a unique IP address on the interface or VLAN where you are configuring VRRP. Let’s go-ahead to the configuration and add the VRRP configuration.

Router2:

• Router2>enable
• Router2#config terminal
• Router2(config)# interface gigabitEthernet 0/1
• Router2(config-if)#no shutdown
• Router2(config-if)#ip address 192.168.10.2 255.255.255.0
• Router2(config-if)#vrrp 1 ip 192.168.10.1
• Router2(config-if)vrrp 1 priority 110
• Router2(config-if)#vrrp1 preempt
• Router2(config-if)#exit
• Router2(config)#do wr

Router3:

• Router3>enable
• Router3#config terminal
• Router3(config)# interface gigabitEthernet 0/1
• Router3(config-if)#no shutdown
• Router3(config-if)#ip address 192.168.10.3 255.255.255.0
• Router3(config-if)#vrrp 1 ip 192.168.10.1
• Router3(config-if)vrrp 1 priority 100
• Router3(config-if)#vrrp 1 preempt
• Router3(config-if)#exit
• Router3(config)#do wr

When we type vrrp in the command prompt we are stating to the router that we are configuring vrrp on this interface, the number next to it is the VRRP group we are configuring, the range of the group is from 1 to 254.

The groups required to be matched on all equipment participating in the VRRP election process, and the last part of the configuration we are stating what the floating IP address is. We have added the group 1 to configuration.

We have set the priority of both routers. Router2 is configured with higher value, so this will be a master router. If Router2 fails, the Router3 will become master. The preemption is enabled, so whenever Router2 recover from failure, it will again become a master router.