Deterministic selection of an optimal restoration route in a telecommunications network

摘要

A deterministic approach further refines the self healing network (SHN) distributed restoration algorithm (DRA) used for restoring traffic disrupted between two adjacent nodes. Upon detection of a fault, the sender node constructs a restoration signal that includes a weighed identifier field. The restoration message is broadcast to tandem nodes each of which had been provisioned with a memory table having stored therein a plurality of weights each associated with a particular spare link connected to the node. Upon detection of an incoming restoration message, a tandem node retrieves from its table the weight associated with the spare link from which the restoration message was received. The weighed identifier is retrieved from the restoration message and updated with the weight that the tandem node had retrieved from its table. The updated weighed identifier is reinserted to the restoration message and the updated restoration message is broadcast to downstream nodes for further propagation to the chooser node. As the restoration message arrives at each succeeding tandem node, the weighed identifier continues to be updated. The chooser node, upon receipt of the restoration message, retrieves the weighed identifier and compares the weighed identifier with other weighed identifiers of other restoration messages received before a restoration time out. Based on this comparison, the chooser node chooses an alternate route with the best weighed identifier.