Abstract: An optical communication system includes a first optical communication apparatus configured to insert a wavelength control signal in a main signal to produce a modified main signal; convert the modified main signal into a first optical signal; and transmit the first optical signal, and a second optical communication apparatus configured to receive the first optical signal; extract the wavelength control signal from the received first optical signal; determine a wavelength of a second optical signal based on the extracted wavelength control signal; and transmit the second optical signal to the first optical communication apparatus.

Abstract: An optical communication system includes a first optical communication apparatus configured to insert a wavelength control signal in a main signal to produce a modified main signal; convert the modified main signal into a first optical signal; and transmit the first optical signal, and a second optical communication apparatus configured to receive the first optical signal; extract the wavelength control signal from the received first optical signal; determine a wavelength of a second optical signal based on the extracted wavelength control signal; and transmit the second optical signal to the first optical communication apparatus.

Abstract: The present invention provides a communication control system that monitors a status of a transmission line, and can dynamically change a communication band used by a communication device included in an access line based on the monitored result. Line terminal devices (200-1 to 200-n) monitor a status of transmission lines (1, 2) connected to the line terminal devices (200-1 to 200-n), and control a communication band used for performing data communication in accordance with the status of the transmission lines (1, 2). A line aggregation device (300) monitors a status of transmission lines (2, 3), and controls a communication band used for performing data communication in accordance with the status of the transmission lines (2, 3).

Abstract: An optical communication system includes a first optical communication apparatus configured to insert a wavelength control signal in a main signal to produce a modified main signal; convert the modified main signal into a first optical signal; and transmit the first optical signal, and a second optical communication apparatus configured to receive the first optical signal; extract the wavelength control signal from the received first optical signal; determine a wavelength of a second optical signal based on the extracted wavelength control signal; and transmit the second optical signal to the first optical communication apparatus.

Abstract: An ATM (Asynchronous Transfer Mode) bridge device is provided which is capable of removing unwanted ATM network traffic transmitted by a loop packet, of avoiding confusion of a layer 2 network caused by occurrence of erroneous learning, of rapidly identifying a point where a loop has been formed, and of preventing simultaneous formation of loops among a plurality of points caused by loop setting in a plurality of interfaces. The ATM bridge device has functions of learning a MAC (Media Access Control) address of a packet transmitted from the ATM bridge device, of filtering and monitoring a MAC address of a packet input from an ATM network and judges, when receiving a packet output from the ATM bridge device, the input packet as a loop-back packet to scrap the packet and to notify an upper network layer of the loop-back packet.