DATA TRANSMISSION SYSTEM, TRANSMISSION RATE CONTROLLING METHOD, RECEIVING TERMINAL AND TRANSMITTING TERMINAL

摘要

Provided is a data transmission system (100) wherein: a transmitting terminal (2) and a receiving terminal (1) are connected to each other by a network (3); the transmitting terminal (2) transmits data packets to the receiving terminal (1) via the network (3); and the receiving terminal (1) transmits back a control packet to the transmitting terminal (2) upon receiving the data packets from the transmitting terminal (2). A network data measuring unit (11) of the receiving terminal (1) measures network data on the basis of which the congestion level of the network can be predicted. A control packet transmission rate determining means predicts, in each period having a predetermined length, the congestion level of the network by using the network data that has been measured over the period by the network data measuring unit (11), and determines, in accordance with the congestion level thus predicted, the transmission rate of a control packet to be transmitted from the receiving terminal (1). This configuration makes it possible to reliably follow the congestion level of the network.