Abstract: A method of tracking the availability of a logical connection to a router in a data transmission system including a network, a plurality of customer servers, and at least two network access routers using Virtual Router Redundancy Protocol or the like to set up a primary interface router. The method is automatically achieved in each router by periodically tracking at least one logical connection between the primary interface router and a neighbor router connected to the network. Virtual Router Redundancy Protocol sets up one of the backup routers as primary interface router when the logical connection has failed.