COMMUNICATION DEVICE AND COMMUNICATION CONTROL METHOD

PROBLEM TO BE SOLVED: To evade the cancellation of an active state to evade the elongation of a time required for the changeover of a route.SOLUTION: A communication device, which becomes an active state when an active first communication device having priority higher than the priority of the self-device, detects a failure of the first communication device to cause the self-communication device to shift to an active state which, if a first signal based on a redundant protocol, arrives at the communication device from the first communication device, is not received for a predetermined period through a communication channel including a logical channel having a plurality of bundled physical channels to be blocked when the number of normal channels falls below a threshold. If the communication device shifted to the active state receives the first signal from the first communication device, the active state is canceled, whereas if the communication device does not receive a second signal, which is transmitted from the first communication device at a shorter interval than the transmission interval of the first signal, for a predetermined period, to detect a failure related to the first communication device, the priority of the communication device is made higher than the first communication device.SELECTED DRAWING: Figure 7 【課題】アクティブ状態の解除を回避して経路の切り替えに要する時間の長期化を回避する。【解決手段】自身の優先度より高い優先度を有するアクティブの第１通信装置の障害時にアクティブ状態となる通信装置が、正常な物理回線の数が閾値を下回る場合に閉塞される、複数の物理回線を束ねた論理回線を含む通信路を通じて通信装置に到達する第１通信装置からの、冗長化プロトコルに基づく第１信号が、所定期間受信されない場合に、第１通信装置の障害を検出して通信装置をアクティブ状態に遷移させる。アクティブ状態に遷移した通信装置が、第１通信装置からの第１信号を受信した場合には、アクティブ状態を解除し、第１信号の送信間隔より短い送信間隔で第１通信装置から送信される第２信号が所定期間受信されず第１通信装置に係る障害を検出した場合には、通信装置の優先度を第１の通信装置より高くする。【選択図】図７