| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a receiving state notifying method, etc., capable of contributing to the relaxation of transmission line congestion due to a retransmission request and also surely supplying information showing the receiving state of a receiver being in a worst receiving state to a transmitter. SOLUTION: A NAK (negative acknowledge character) detecting part 23 detects a NAK supplied to a buffer 22. A deciding part 24 decides whether or not to be the first NAK for a multicast packet having a sequence number in response to the sequence number in the extracted NAK, makes a NAK transmitting part 26 generate a NAK obtained by replacing the receiving state in the NAK with the worst receiver information held by a NAK holding part 25 for the first NAK, and discards the NAK if the NAK is not the first NAK.</p> |
