| 摘要 |
<p>In a relay device which relays between two TCP communication items of a LAN side and a WAN side, even in a case where 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 value of a 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. Further, when rwnd decreases so as to be less than a predefined threshold value and then exceeds the threshold value again, an ACK packet in which a value of the reception window size (rwnd) is described is immediately transmitted to a transmission terminal of the LAN side.</p> |
