Communication device, communication method, communication system and communication program

A communication method that is used in a communication system in which a plurality of communication devices is connected by an optical ring network, one of the communication devices being a master communication device, the other ones of the communication devices being slave communication devices,

• wherein
• the master communication device transmits a control signal for controlling transmission timings to transmit optical signals to a plurality of the slave communication devices by time-division multiplexing, and
• each slave communication device transmits an optical signal to the optical ring network on a basis of a transmission timing of the control signal received from the master communication device, and, when the control signal is not received in a predetermined period, determines the master communication device not to be operating properly, and causes the subject communication device to operate as a new master communication device.

A communication system in which a plurality of communication devices is connected by an optical ring network, one of the communication devices being a master communication device, the other ones of the communication devices being slave communication devices,

• wherein
• the master communication device transmits a control signal for controlling transmission timings to transmit optical signals to a plurality of the slave communication devices by time-division multiplexing, and
• each slave communication device transmits an optical signal to the optical ring network on a basis of a transmission timing of the control signal received from the master communication device, and, when the control signal is not received in a predetermined period, determines the master communication device not to be operating properly, and causes the subject communication device to operate as a new master communication device.