American Telephone & Telegraph Co., At&t Bell Laboratories

Richard E Wallace

David Michael Rouse

Charles M Zelms

Allen D Fergeson

David B Brown

Joseph W Darnell

Apparatus and method for identifying the location of a lost token signal continuously transmitted on transmission paths interconnecting nodes of a network to sequentially enable the nodes to write data onto the network. The arrival of the token signal at each node is recorded in counter states of a token track counter corresponding with the node. The recorded binary counter states are compared upon the failure of the token signal to arrive at a node to detect mismatches and transitions occurring between adjacent nodes counter states identifying the network location of the lost token signal.

Method and apparatus for identifying location of a lost token signal in

A data communication network comprising a plurality of nodes interconnecting transmission paths in a ring structure arranged to propagate data messages between data systems coupled to the network by the nodes in opposite directions around the network ring structure. An executive node having ring interface units interconnecting ones of the transmission paths is arranged to selectively couple a network control processor with various sectors of the transmission paths to enable the network control processor to control the traffic flow of data messages on the data communication network.

Ring packet switch

A data communication network comprising ring transmission paths (0,1) interconnecting ring interface nodes (RI1, RI2, RI3) coupled with a node processor and data systems and arranged to propagate data messages along the ring transmission paths between the data systems. Each node is arranged to detect failure of the node to propagate a data message to another node and to flush the data communication network by force reading data messages off the ring transmission paths into the blocked node processor. A node is arranged to automatically maintain and restore operation of the data communication network by loop connecting ones of the ring transmission paths together to isolate segments of the network experiencing trouble and to transfer maintenance and diagnostic data messages between ones of the looped ring transmission paths to restore ring transmission paths and nodes located in isolated segments of the network to service.

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Newark, OH, United States of America

Richard E Wallace