Congestion control network relay device and method

A congestion control network relay program for relaying data between a plurality of transmission paths, wherein the congestion control network relay program causes a computer to function as:

• acknowledgment packet detector means for detecting, from among packets transferred via the transmission paths, an acknowledgment packet by means of which a receiving-side device returns an identification number of a data packet received thereby to a transmitting-side device;
• receive packet manager means for registering, in acknowledgment information memory means, the identification number of the data packet whose reception has been acknowledged by the receiving-side device, based on the acknowledgment packet detected by the acknowledgment packet detector means;
• packet reception determination means for comparing an identification number of a data packet transmitted from the transmitting-side device with the identification number stored in the acknowledgment information memory means, to determine whether or not the data packet transmitted from the transmitting-side device has already been received by the receiving-side device;
• and
• packet transfer means for discarding the data packet transmitted from the transmitting-side device if it is judged by the packet reception determination means that the data packet has already been received by the receiving-side device, and transferring the data packet transmitted from the transmitting-side device to the receiving-side device if it is judged by the packet reception determination means that the data packet has not yet been received by the receiving-side device.

A congestion control network relay method for relaying data between a plurality of transmission paths, comprising the steps of:

• causing acknowledgment packet detector means to detect, from among packets transferred via the transmission paths, an acknowledgment packet by means of which a receiving-side device returns an identification number of a data packet received thereby to a transmitting-side device;
• causing receive packet manager means to register, in acknowledgment information memory means, the identification number of the data packet whose reception has been acknowledged by the receiving-side device, based on the acknowledgment packet detected by the acknowledgment packet detector means;
• causing packet reception determination means to compare an identification number of a data packet transmitted from the transmitting-side device with the identification number stored in the acknowledgment information memory means, and thereby determine whether or not the data packet transmitted from the transmitting-side device has already been received by the receiving-side device;
• and
• causing packet transfer means to discard the data packet transmitted from the transmitting-side device if it is judged by the packet reception determination means that the data packet has already been received by the receiving-side device, and to transfer the data packet transmitted from the transmitting-side device to the receiving-side device if it is judged by the packet reception determination means that the data packet has not yet been received by the receiving-side device.