Bandwidth variable communication method, bandwidth variable communication apparatus, transmission bandwidth determination apparatus, transmission bandwidth determination method, node apparatus, communication path setting system, communication path setting

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.