312 CHAPTER 13: V IRTUAL ROUTER R EDUNDANCY (VRRP)Layer 2SwitchingModules3 MultilayerSwitchingModulesip vrrp define Defines a virtual router on a Multilayer Switching Module.Valid Minimum Abbreviationip v defImportant Considerationsn Authentication passwords can be up to eight alphanumericcharacters.n Regarding primary routers, consider the following:n You can define one Primary router per VLAN.n Primary routers own the IP addresses that you associate with avirtual router.n When you define a Primary virtual router, the possible VLANs thatyou can select are the IP VLANs on the router that have no virtualrouters configured.n The virtual router ID (VRID) must be unique across all locallyattached LAN segments and unique for the local router.n When you define a Primary virtual router, you cannot use the VRIDof a virtual router that is already defined on the module or theVRID of a neighboring VRRP router.n Regarding backup routers, consider the following:n Backup routers back up the primary router of a specified virtualrouter and assume Master state responsibilities for the virtualrouter should the primary router fail.n When you define a Backup virtual router, you cannot use the VRIDof a primary router that is defined on the module. You cannotdefine a Primary and Backup VRRP router for the same virtualrouter on the same routing device.n Regarding the address mode, consider the following:n In auto-learn mode, a module learns the IP addresses toassociate with the specified VRID.n In IP-address mode, the module prompts you to select theinterface index from a list.n After a reboot, the address learning process restarts for each virtualrouter in auto-learn address mode.
