BAND-VARIABLE COMMUNICATION METHOD, BAND-VARIABLE COMMUNICATION APPARATUS, TRANSMISSION BAND DECIDING APPARATUS, TRANSMISSION BAND DECIDING METHOD, NODE APPARATUS, COMMUNICATION PATH SETTING SYSTEM, AND COMMUNICATION PATH SETTING METHOD

摘要

A band-variable communication method is provided wherein the bit rate is constant in all optical paths and further the frequency bands can be effectively used. According to the band-variable communication method, when a network managing apparatus sets or changes an optical path passing through a plurality of communication apparatuses, an optical signal quality degradation amount along the optical path is measured or calculated; out of modulation formats with which transmission can be performed on the conditions of the optical signal quality degradation amount and a desired bit rate B (bit/s), a modulation format using the narrowest spectrum band is selected; and control information is exchanged, based on a result of modulation format selection, between the network managing apparatus and the control means of each of the communication apparatuses on the optical path. A band-variable communication apparatus receives the control information and changes, based on the received control information, the passband.