Patent ID: 8509059

Claim:
A method for operating a router in a communication system using a Virtual Router Redundancy Protocol (VRRP), comprising: receiving, by a first router operating as a backup router, an advertisement message from a second router operating as a master router during a first period; checking, by the first router, a session state of the second router using a Bi-directional Forwarding Detection (BFD) module during a second period that is shorter than the first period; upon detecting a session down for the second router by the BFD module, comparing a difference between a time at which the advertisement message was last received and a time at which the session down was detected, with the first and second periods, and determining an operation state of the second router according to comparison results; and if the second router is in a down state based on the comparison results, switching, by the first router, from the backup router to a master router, and sending an advertisement message to the second router.