摘要 |
In a ring network system, a first node device includes means for sending out a control signal for controlling one of a plurality of second node devices so as to allow signals transmitted over a protection band to pass through the second node device; each of the second node devices includes means for receiving the control signal sent out from the first node device or another second node device, means for controlling the signals transmitted over the protection band to pass through the second node device during the reception of the control signal, and means for transferring the control signal to the adjacent first node device or to the adjacent second node device during the reception of the control signal; and the first node device further includes means for receiving the control signal transferred from the adjacent second node device.
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