Abstract: In a packet transfer system, a transmission-side relay device extracts and integrates data included in a packet transmitted from a transmission device to obtain a packet data stream, extracts data from the packet data stream to obtain a data block, encodes the data block with an error correction code to generate redundant data as a redundant block, generates an error correction data stream obtained by integrating the data block and the redundant block, and packetizes the error correction data stream and transmits the packetized error correction data stream. A reception-side relay device restores missing data using redundant data included in the received data in a case in which there is missing data. The system enables packet transmission and reception to be efficiently performed even in a high loss rate environment.

Abstract: To provide a packet processing device that prevents a reduction in the efficiency of data communication. A packet processing device 100 estimates a time, which is taken until an acknowledgement corresponding to a packet is received after transmitting the packet to a client 30, as the round-trip delay time of the packet, determines the size of data that is divided into packets and is continuously transmitted to the client 30, and updates the transmission rate of packets transmitted to the client 30 according to the data size and the round-trip delay time.