Mci Communications Corporation

Steve Sellers

William D Croslin

Mark W Sees

A method and system for initiating distributed restoration of a communications network following the failure of one or more network components. Restoration is conducted in a distributed fashion by all the restoration nodes of the network. When a restoration node detects failure of a segment connected to it, the restoration node monitors its segments for a period of time and then sends a failure message to other restoration nodes of the network indicating the number of segments connected to it that have failed. When restoration nodes receive failure messages, they compare the count of failed segments contained in the messages to a range of counts of failures for the detecting node that are locally stored on each restoration node. By this comparison, the restoration nodes can determine whether the network has quiesced to a relatively stable state following a network outage. Once the network has reached a stable state, all the restoration nodes simultaneously initiate a local restoration process.

Method for initiating a distributed restoration process

A distributed method and system for excluding segments from use in bypassing a failed component. Prior to failure of a segment, the restoration system at a central location identifies each path in the communications network. A path is a unique sequence of installations that a segment traverses. The restoration system then creates a mapping of the ports of the restoration nodes to the paths of the segments connected to each port. The restoration system then identifies for each path the set of paths that are interdependent. A pair of paths are interdependent when both paths traverse a common pair of installations. The restoration system then downloads to each restoration node the mappings for its ports along with an indication of the paths that are interdependent with the path of each segment connected to the restoration node. Following failure of a segment, the restoration node that detects the failure uses the downloaded mapping to identify the failed path and notifies the other restoration nodes of the failed path. The restoration system at each restoration node then excludes each segment that has a path that is interdependent with the failed path when implementing a restoral route.

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Colorado Springs, CO, United States of America

Steve Sellers