Patent ID: 9319131
Filing Date: 2016-04-19
CPC Classification: H04B,H04J,H04Q

Claim Text:
1. A network management system for managing pre-planned alternative paths in a wavelength switched optical network having a number of nodes and the network management system having: an input for receiving an indication of a fault affecting a traffic flow, the traffic flow having a working path and two or more pre-planned alternative paths from a source node to a destination node, a processing part arranged to determine if, after the fault, a number of available alternative paths for the respective traffic flow drops to a threshold, the threshold being at least one, and if so, to determine a new alternative path through the network for the respective traffic flow from the same source node to the same destination node, and a path set up part arranged to communicate with the nodes along the new alternative path to set up the new alternative path in the nodes, to enable one or more of the nodes to move the traffic flow onto the new alternative path in the event of further faults without waiting for input from the network management system.