Abstract: A bandwidth variable communication method is provided that enables effective use of frequency bandwidths in which the bit rate is constant in every optical path. The bandwidth variable communication method includes, when a network management apparatus sets or changes an optical path that passes through plural communication apparatuses, measuring or obtaining an optical signal quality deterioration amount in a route of the optical path; selecting a modulation format in which a spectrum bandwidth is the narrowest from among modulation formats by which transmission is available on conditions of the optical signal quality deterioration amount and a desired bit rate B (bit/s); and exchanging control information between the network management apparatus and a control unit of each communication apparatus on the optical path route. A bandwidth variable communication apparatus receives the control information, and changes a passband based on the received control information.

Abstract: A bandwidth variable communication apparatus includes: a route exchange unit including a route exchange function for switching an output port of a stream signal of one or more wavelengths input from an input port based on both or a part of wavelength and time, and including a bandwidth change function for changing passable frequency bandwidth in a section from the input port to the output port through which the stream signal passes; and a control unit including a control information transmit-receive function for transmitting and receiving control information for both or a part of the route exchange function and the bandwidth change function of the route exchange unit, and including a control function for controlling the route exchange unit based on the control information. All or a part of the input ports and the output ports are connected to other communication apparatuses via transmission routes.

Abstract: A bandwidth variable communication method is provided that enables effective use of frequency bandwidths in which the bit rate is constant in every optical path. The bandwidth variable communication method includes, when a network management apparatus sets or changes an optical path that passes through plural communication apparatuses, measuring or obtaining an optical signal quality deterioration amount in a route of the optical path; selecting a modulation format in which a spectrum bandwidth is the narrowest from among modulation formats by which transmission is available on conditions of the optical signal quality deterioration amount and a desired bit rate B (bit/s); and exchanging control information between the network management apparatus and a control unit of each communication apparatus on the optical path route. A bandwidth variable communication apparatus receives the control information, and changes a passband based on the received control information.

Abstract: A bandwidth variable communication apparatus includes: a route exchange unit including a route exchange function for switching an output port of a stream signal of one or more wavelengths input from an input port based on both or a part of wavelength and time, and including a bandwidth change function for changing passable frequency bandwidth in a section from the input port to the output port through which the stream signal passes; and a control unit including a control information transmit-receive function for transmitting and receiving control information for both or a part of the route exchange function and the bandwidth change function of the route exchange unit, and including a control function for controlling the route exchange unit based on the control information. All or a part of the input ports and the output ports are connected to other communication apparatuses via transmission routes.