Optical transmission system and optical node

1. An optical transmission system comprising a plurality of optical nodes capable of dropping or adding optical signals and a monitoring and controlling device that monitors and controls the plurality of optical nodes, wherein:

each of the optical nodes is provided with an optical transceiver and an optical add-drop unit that sends out to a transmission line or receives from the transmission line transmit or receive signals from the optical transceiver;

the optical add-drop unit:

regarding add signals, selects the optical signals of the optical transceiver of an own node thereof or optical signals from a second transmission line for optical signals to be sent out to a first transmission line, and

regarding drop signals, drops signals from the first transmission line to the own node thereof, and sends out to the same to the second transmission line or blocks the same from being sent out to the second transmission line; and

an alarm inhibiting device is further provided that, regarding transmit signals from a first optical transceiver of a first optical node, inhibits any unexpected alarm from being issued by the first optical transceiver when selection is made by the optical add-drop unit of a second optical node to drop the signals to the own node thereof and to send the signals out to a transmission line in a downlink direction.

2. The optical transmission system according to claim 1 ,

wherein the alarm inhibiting device is related to notification for controlling purpose or maintaining alarm inhibition in setting path to the first optical transceiver by the monitoring and controlling device.

3. The optical transmission system according to claim 2 ,

wherein when the first optical transceiver is selected as a transmitting terminal for a plurality of paths and transmit signals from the first optical transceiver are received by optical transceivers of a plurality of different optical nodes, path names which place the first optical transceiver and the plurality of optical transceivers in one-to-one correspondence are assigned to register and manage the plurality of paths being related to one another.

4. The optical transmission system according to claim 2 ,

wherein in a state in which the first optical transceiver is selected as a transmitting terminal for a plurality of paths and paths are set for causing transmit signals from the first optical transceiver to be received by optical transceivers of a plurality of different optical nodes, a path having the transmitting terminal of the plurality of paths as one terminal and another optical transceiver different from the plurality of optical transceivers is added.

5. The optical transmission system according to claim 1 ,

wherein the alarm inhibiting device is based on transmission only of transmit signals from the optical transceiver of the second optical node to the first optical transceiver of the first optical node.

6. The optical transmission system according to claim 5 ,

wherein when the first optical transceiver is selected as a transmitting terminal for a plurality of paths and transmit signals from the first optical transceiver are received by optical transceivers of a plurality of different optical nodes, path names which place the first optical transceiver and the plurality of optical transceivers in one-to-one correspondence are assigned to register and manage the plurality of paths being related to one another.

7. The optical transmission system according to claim 5 ,

wherein in a state in which the first optical transceiver is selected as a transmitting terminal for a plurality of paths and paths are set for causing transmit signals from the first optical transceiver to be received by optical transceivers of a plurality of different optical nodes, a path having the transmitting terminal of the plurality of paths as one terminal and another optical transceiver different from the plurality of optical transceivers is added.

8. The optical transmission system according to claim 1 ,

wherein when the first optical transceiver is selected as a transmitting terminal for a plurality of paths and transmit signals from the first optical transceiver are received by optical transceivers of a plurality of different optical nodes, path names which place the first optical transceiver and the plurality of optical transceivers are assigned in one-to-one correspondence to register and manage the plurality of paths being related to one another.

9. The optical transmission system according to claim 1 ,

wherein in a state in which the first optical transceiver is selected as a transmitting terminal for a plurality of paths and paths are set for causing transmit signals from the first optical transceiver to be received by optical transceivers of a plurality of different optical nodes, a path having the transmitting terminal of the plurality of paths as one terminal and another optical transceiver different from the plurality of optical transceivers is added.

10. An optical node comprising an optical transceiver and an optical add-drop unit that sends out to a transmission line or receives from the transmission line transmit or receive signals from the optical transceiver,

wherein when the optical add-drop unit, regarding drop signals, drops signals from a first transmission line to the optical node and sends out the signals from the first transmission line to a second transmission line, the optical add-drop unit, regarding add signals, selects optical signals of the optical transceiver of the optical node as optical signals to be sent out to the first transmission line and blocks receive signals from the second transmission line.