Communication system, communication device, and communication method

A communication system, comprising:

• a first device including first circuitry configured to transmit first data;
• a second device including second circuitry configured to receive the first data from the first circuitry of the first device;
• a third device including third circuitry;
• a fourth device including fourth circuitry;
• and
• a storage device including fifth circuitry configured to store correspondence information which associates a first address of the second device and a second address of the third device, wherein
• the second circuitry of the second device receives the first data from the first circuitry of the first device and determines whether the second device is in a first state or a second state, and,
• when it is determined that the second device is in the first state,
• the second circuitry of the second device notifies the storage device of the first address of the second device,
• the storage device notifies the second circuitry of the second device of the second address of the third device associated with the first address of the second device based on the correspondence information, and
• the second circuitry of the second device transmits the first data to the third device using the second address notified by the storage device, and
• when it is determined that the second device is in the second state,
• the second circuitry of the second device transmits the first data to the fourth device,
• the second circuitry of the second device notifies the fourth device of the first address of the second device,
• the fourth circuitry of the fourth device receives the first data and notifies the storage device of the first address of the second device notified by the second device,
• the fifth circuitry of the storage device notifies the fourth device of the second address of the third device associated with the first address of the second device based on the correspondence information, and
• the fourth circuitry of the fourth device transmits the first data to the third device using the second address notified by the storage device.