Data communications system, data sender, data receiver, data communications method, and computer program

A data sender for sending streaming data, comprising:

• a packet sending processor for sending data packets containing data to be sent;
• a network status monitoring unit for monitoring the network status;
• a data-sender-side controller for controlling, on the basis of the network status monitored by the network status monitoring unit, an error control mode for the transmitted packets;
• and
• a retransmission controller for extracting a data packet to be retransmitted in accordance with a retransmission request message packet received from a data receiver.

A data receiver for receiving streaming data, comprising:

• a packet reception processor for receiving data packets from a data sender;
• a network status monitoring unit for monitoring the network status;
• an error correction controller for detecting an error or packet loss in the data packets received from the data sender and performing error-compliant processing;
• a retransmission request controller for determining, on the basis of the detection of the error or packet loss in the data packets received from the data sender, whether to send a retransmission request message packet serving as a data packet retransmission request to the data sender;
• and
• a layer selection controller for selecting the data to be processed on the basis of a monitoring result by the network status monitoring unit.

A data communications method for performing streaming data transmission between a data sender and a data receiver, comprising:

• a packet sending step of sending data packets containing data to be sent;
• a network status monitoring step of monitoring the network status;
• a data-sender-side controlling step of controlling, on the basis of the network status monitored in the network status monitoring step, an error control mode for the transmitted packets;
• and
• a retransmission controlling step of extracting a data packet to be retransmitted in accordance with a retransmission request message packet received from the data receiver;
• and
• a packet receiving step of receiving the data packets from the data sender;
• an error correction controlling step of detecting an error or packet loss in the data packets received from the data sender and performing error-compliant processing;
• and
• a retransmission request controlling step of determining, on the basis of the detection of the error or packet loss in the data packets received from the data sender, whether to send the retransmission request message packet serving as a data packet retransmission request to the data sender.

A computer program for sending streaming data, comprising:

• a packet sending step of sending data packets containing data to be sent;
• a network status monitoring step of monitoring the network status;
• a control step of controlling, on the basis of the network status monitored in the network status monitoring step, an error control mode for the transmitted packets;
• and
• a retransmission controlling step of extracting a data packet to be retransmitted in accordance with a retransmission request message packet received from a data receiver.

A computer program for receiving streaming data, comprising:

• a packet receiving step of receiving data packets from a data sender;
• an error correction controlling step of detecting an error or packet loss in the data packets received from the data sender and performing error-compliant processing;
• a retransmission request controlling step of determining, on the basis of the detection of the error or packet loss in the data packets received from the data sender, whether to send a retransmission request message packet serving as a data packet retransmission request to the data sender;
• and
• a layer selection controlling step of selecting data to be processed on the basis of the monitoring result in the network status monitoring unit.