Communication device

摘要

A relay device relays between two TCP communication items of a LAN side and a WAN side. When a line bandwidth of the WAN side is smaller than a line bandwidth of the LAN side, buffer overflow in a LAN side reception buffer and a WAN side transmission buffer of the relay device is prevented, and a connection is prevented from being forced to be canceled. A value of a reception window size (rwnd) described in an ACK packet returned to a transmission terminal of the LAN side is controlled based on a transmission throughput, a discarding rate, and an RTT measured in TCP communication of the WAN side, and a total size of unarranged data and a size of arranged data in a reception buffer of the LAN side and a size of untransmitted data and ACK awaiting data in a transmission buffer of the WAN side.

主权项

1. A communication device which relays TCP communication of a first network and a second network, comprising:
a buffer that temporarily accumulates relay data which is received from the first network and is relayed to the second network; a reception unit that calculates a size of the relay data accumulated in the buffer; and a transmission bandwidth control unit that measures a practical transmission throughput to the second network, wherein the reception unit calculates a value of a reception window size which is described in an ACK packet transmitted in the TCP communication of the first network side on the basis of the size of the relay data and the transmission throughput.