Mci Communications Corporation

Mci, Inc.

Ching-Hua Chow

Jasvantrai C Shah

John David Allen

Sami A Syed

John D Bicknell

Stephen C McCaughey

A system and method for restoration of a disrupted telecommunications path between a source node and a destination node via at least one tandem node. The operation of the present invention proceeds in five phases: notification, broadcast, path trace-out, confirmation and cleanup. In the notification phase, the path's source and destination nodes are notified of the disruption. In the broadcast phase, the network is flooded with PACK messages to locate restoration paths; selective rebroadcasting of the PACK messages limits the volume of restoration message traffic. In the path trace-out phase, bandwidth is conservatively reserved along the restoration paths indicated by the PACK messages. In the confirmation phase, restoration paths are built up step-wise along the traced-out paths, thereby restoring the disrupted path between the source and destination nodes. In the clean-up phase, all of the network resources that were allocated to restoration of the disrupted path, and that are no longer needed, are released.

System and method for restoring a telecommunications network using

A fast distributed network restoration system and method therefor for restoring disrupted traffic, due to a cut link, in a digital cross-connect system (DCS) network utilizes a two-prong approach whereby both disrupted ends of the cut link simultaneously send out restore messages. To this end, upon detection of a cut link, the end nodes are respectively designated as a Gray Origin node and a Black Origin node. The Gray Origin node begins to broadcast Gray restoration request messages while the Black Origin node begins to broadcast Black restoration request messages to their respective neighbor nodes. As soon as an intermediate node receives one of the restoration request messages, depending on the color attribute of the message, that intermediate node is identified as either a Gray or Black node. Once a network node has received both Gray and Black restoration request messages, a restoration path is identified and that node begins to connect the spare channels of the links over which the request messages arrived. A system for effecting the method of the present invention is also disclosed.

System and method for restoring a telecommunications network based on a

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Colorado Springs, CO, United States of America

Ching-Hua Chow