1046 Configuring VRRPWith VRRP, a virtual router is associated with one or more IP addresses thatserve as default gateways. In the event that the VRRP router controlling theseIP addresses (formally known as the master) fails, the group of IP addressesand the default forwarding role is taken over by a Backup VRRP router.What Is the VRRP Router Priority?The VRRP router priority is a value from 1–255 that determines which routeris the master. The greater the number, the higher the priority. If the virtual IPaddress is the IP address of a VLAN routing interface on one of the routers inthe VRRP group, the router with IP address that is the same as the virtual IPaddress is the interface owner and automatically has a priority of 255. Bydefault, this router is the VRRP master in the group.If no router in the group owns the VRRP virtual IP address, the router withthe highest configured priority is the VRRP master. If multiple routers havethe same priority, the router with the highest IP address becomes the VRRPmaster.If the VRRP master fails, other members of the VRRP group will elect amaster based on the configured router priority values. For example, router A isthe interface owner and master, and it has a priority of 255. Router B isconfigured with a priority of 200, and Router C is configured with a priority of190. If Router A fails, Router B assumes the role of VRRP master because ithas a higher priority.What Is VRRP Preemption?If preempt mode is enabled and a router with a higher priority joins the VRRPgroup, it takes over the VRRP master role if the current VRRP master is notthe owner of the virtual IP address. The preemption delay controls how longto wait to determine whether a higher priority Backup router preempts alower priority master. In certain cases, for example, during periods of networkcongestion, a backup router might fail to receive advertisements from themaster. This could cause members in the VRRP group to change their statesfrequently, i.e. flap. The problem can be resolved by setting the VRRPpreemption delay timer to a non-zero value.NOTE: It is not possible to ping the VRRP IP address from the VRRP master onthe PC80xx switches. Use the show vrrp command to display the status ofthe VRRP router
