Available bandwidth search range control method and available bandwidth search range control system

An available bandwidth search range control system comprising a first terminal and a second terminal that are connected to a network,

• wherein the first terminal comprises:
• a local terminal transmission rate acquisition unit which acquires a transmission rate of an application in the first terminal;
• a search range control unit which decides an upper limit of a search range of an available bandwidth of a communication line, using the transmission rate;
• and
• a probe packet transmission unit which transmits a probe packet to the second terminal in a bandwidth less than or equal to the upper limit, and
• wherein the second terminal comprises:
• a probe packet receiving unit which receives the probe packet;
• and
• an available bandwidth estimation unit which estimates the available bandwidth based on the received probe packet;
• wherein the first terminal further comprises:
• a local terminal reception rate acquisition unit which acquires a reception rate of the application and a link speed in the first terminate;
• and
• a full-duplex/half-duplex determination unit which determines whether communication in a section of an access line of the first terminal is full-duplex communication or half-duplex communication, and
• wherein in the case where the communication in the section of the access line of the first terminal is determined as half-duplex communication, the search range control unit sets a value obtained by subtracting the transmission rate of the application in the first terminal and the reception rate of the application in the first terminal form a link speed of the first terminal, as the upper limit of the search range of the available bandwidth.