Loop-back system in a dual ring network

摘要

A loop-back recovery technique used when a failure takes place in a ring network, for transmitting information to a path indicated with a path ID number or the time slot position from a periodic frame. This is achieved by establishing working paths on one of the dual ring line between a transmission node and a receiving node thereof, establishing ring-formed protection paths in a ring line of the direction opposite to the working line, and making a loop-back from the working paths to the corresponding protection paths at a node which detected the failure. The receiving node multiplexes the working and protection paths to receive data from either.