COMMUNICATION DEVICE, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD

摘要

PROBLEM TO BE SOLVED: To make efficient use of a network band even if TCP communication is used for communication between end users in data transfer in a bandwidth-guaranteed network.SOLUTION: A communication device comprises a priority addition unit that adds priority to a transmission packet in order to measure a reference RTT corresponding to distance delay and performs reference RTT measurement by a packet to which high priority is added by the priority addition unit. The communication device measures queueing delay in a network per TCP flow, and determines that it is a congestion state if the measured queueing delay is equal to or more than a preset threshold value. The communication device performs dynamic transmission band control on the basis of a preset guaranteed bandwidth and the congestion state, and thereby makes efficient use of a network band.