Communication device and communication method

A communication device comprising:

• data processing circuitry including a plurality of data processors configured to process data;
• communication circuitry configured to receive, from another communication device, a plurality of packets, each of which includes a first header, a second header and a piece of the data, the first header including a first sequence number, the second header including an identifier that is used to identify one of the plurality of data processors and a second sequence number that is assigned to the piece of the data, the second sequence number being assigned independently for each data processor to which the piece of the data is to be provided;
• and
• processing circuitry configured to process packets received by the communication circuitry, the packets including a first packet, a second packet received after the first packet and a third packet received after the first packet,
• the first sequence number in the second packet is higher than the first sequence number in the first packet,
• the identifier included in the second packet is different from the identifier included in the first packet,
• the first sequence number included in the third packet is higher than the first sequence number included in the first packet, and
• the identifier included in the third packet is the same as the identifier included in the first packet, wherein
• the communication circuitry unsuccessfully receives the first packet and successfully receives the second packet and the third packet,
• the processing circuitry is configured to:
• detect a loss of the first packet based on the first sequence number,
• detect a loss of the piece of the data included in the first packet and specify the second sequence number of the piece of the data included in the first packet based on the second sequence number included in the third packet,
• the communication circuitry is configured to transmit a retransmission request for the piece of the data included in the first packet based on the second sequence number of the piece of the data included in the first packet, to the another communication device, and
• even when a retransmitted packet including a piece of retransmission requested data is not yet received in the communication circuitry, the processing circuitry provides the piece of the data in the second packet to the data processor corresponding to the data processor identified by the identifier in the second packet, and does not provide the piece of the data in the third packet to the data processor corresponding to the data processor identified by the identifier in the third packet before the retransmitted packet is received in the communication circuitry.

A communication method that is executed by a communication device, comprising:

• independently determining, for a piece of data acquired by each of a plurality of data acquirers, a second sequence number, and
• generating a plurality of first packets, each of which including a first header, a second header and the piece of the data, the first header including one of first sequence numbers assigned to the plurality of first packets, the second header including the second sequence number assigned to the piece of the data and an identifier that identifies at least one of a data acquirer having acquired the piece of the data or an application corresponding to the piece of the data;
• transmitting the plurality of first packets;
• receiving a retransmission request for the piece of the data to which the second sequence number is assigned;
• generating, in response to the retransmission request, a second packet and a third packet,
• the second packet including a first header, two second headers, a piece of retransmission requested data and a piece of first data different from the piece of retransmission requested data,
• the first header in the second packet including a first sequence number different from the first sequence number included in a first packet including the piece of retransmission requested data,
• one of the two second headers in the second packet including (i) a second sequence number which is the same as the second sequence number included in the first packet including the piece of retransmission requested data, and (ii) an identifier which is the same as the identifier included in the first packet including the piece of retransmission requested data, and
• the other of the two second headers in the second packet including (i) a second sequence number which is assigned to the piece of the first data and is different from the second sequence number included in the first packet including the piece of retransmission requested data and (ii) a first identifier different from the identifier included in the first packet including the piece of retransmission requested data, and
• the third packet including a first header, two second headers, the piece of retransmission requested data and a piece of second data different from the piece of retransmission requested data,
• the first header in the third packet including a first sequence number different from the first sequence number included in the first packet including the piece of retransmission requested data,
• one of the two second headers in the third packet including (i) a second sequence number which is the same as the second sequence number included in the first packet including the piece of retransmission requested data and (ii) an identifier which is the same as the identifier included in the first packet including the piece of retransmission requested data, and
• the other of the two second headers in the third packet including (i) a second sequence number which is assigned to the piece of the second data and is different from the second sequence number included in the first packet including the piece of retransmission requested data (ii) a second identifier which is different from the identifier included in the first packet including the piece of retransmission requested data and is also different from the first identifier, and
• transmitting the second packet and the third packet in parallel, thereby making transmission of the piece of retransmission requested data redundant.