Patent ID: 7929420
Filing Date: 2011-04-19
Classification: H04L

Abstract:
1. A method for learning which Virtual Router Redundancy Protocol (VRRP) backup routers are configured to assume responsibility for a virtual IP address upon failure of a master VRRP router associated with the virtual IP address, the method comprising the steps of: causing a VRRP query message identifying the virtual IP address to be transmitted on a network to a set of VRRP backup routers on the network, the set of VRRP backup routers including both VRRP backup routers that are configured to assume responsibility for the virtual IP address upon failure of the master VRRP router for the virtual IP address, and VRRP backup routers that are not configured to assume responsibility for the virtual IP address upon failure of the master VRRP router for the virtual IP address; and receiving, in response to the VRRP query message, VRRP response messages relating to the virtual IP address only from the VRRP backup routers in the set that are configured to assume responsibility for the virtual IP address upon failure of the master VRRP router for the virtual IP address, and not receiving the VRRP response messages relating to the virtual IP address from the VRRP backup routers in the set that are not configured to assume responsibility for the virtual IP address upon failure of the master VRRP router for the virtual IP address.