Sonet/sdh transmission apparatus

A SONET/SDH transmission apparatus, comprising:

• a plurality of interface units that accommodate a plurality of lines;
• and
• mesh wiring that interconnects the plurality of interface units in a mesh pattern in order to allow the plurality of interface units to distribute, to one another, signals on the plurality of lines accommodated by each of the plurality of interface units and information with respect to protection switch operation that is obtained in each of the plurality of interface units,
• wherein the plurality of interface units each include:
• a transmission unit that sends a signal and information to the mesh wiring;
• a reception unit that receives a signal and information from the mesh wiring;
• a time slot interchange unit to which signals on a plurality of lines accommodated by the own interface unit and signals on a plurality of lines accommodated by all the other interface units which are received by the reception unit via the mesh wiring are input, and which can output a signal selected from among the plurality of signals through time slot interchange processing performed on a plurality of the input signals;
• a detection unit that detects alert information with respect to the plurality of lines accommodated by the interface unit itself and alert information with respect to the plurality of lines accommodated by all the other interface units which is received by the reception unit through the mesh wiring;
• and
• a control unit including a logic circuit that virtually executes protection switch operation to be executed based on the alert information detected by the detection unit with respect to the plurality of lines accommodated by the own interface unit to generate control data of the time slot interchange unit which reflects the protection switch operation and is obtained through calculation by the logic circuit and supply the generated control data to the time slot interchange unit.