Patent ID: 6392989
Filing Date: 2002-05-21
Classification: H04L,H04Q

Abstract:
In a communications network having a plurality of switches and transmission links that connect to the switches, a method of protecting at least one connection from failures in the network that disrupt the connection, the method comprising the steps of:determining, from a representation of the network, a primary path across the network for the connection; identifying, in the network, a set of failure units, that, if inoperable, would disrupt the connection; determining, from the representation of the network, a recovery plan for the connection, by deriving a failure condition from a failure of each identified failure unit, the failure condition being a switch associated with the failure unit, and by finding a recovery route through the network for the connection with the failure condition applied to the representation of the network, the recovery plan including all of the recovery routes found for the connection; deriving mapping information for each switch based on the primary and recovery plans; distributing the mapping information to each of the switches to implement the primary and recovery plans; and when the failure of a failure unit occurs, distributing information about the failure to each switch; determining at each switch a failure condition from the failure information; and selecting, at each switch and based on the failure condition, mapping information such that one of the recovery routes of the recovery plan for the connection is implemented.