| 摘要 |
PURPOSE:To improve efficiency for transferring a packet by providing two packet transfer means in a mode to execute the retransmission control of a packet level and a mode not to execute the retransmission control and a means to measure the state of losing the packet during packet transfer in each mode at a picture communication terminal. CONSTITUTION:At a picture communication terminal 1, when the number of times for demand refresh per unit time is more than a threshold value at the number of times of a demand refresh counting part 11 while transferring the packet by using a packet transfer means 9, the control is executed to transfer the packet in the mode for executing the switch retransmission control at the packet transfer means 8 to execute the retransmission control. On the other hand, when the number of times for retransmitting the packet per unit time is made less than the threshold value at the number of times of retransmission counting part 10 while transferring the packet by using the packet transfer means 8 to execute retransmission, the control is execute to switch the operation to a packet transfer means 9, which does not execute the retransmission control, and to transfer the packet in the mode not to execute the retransmission control. Thus, the high transfer efficiency is realized regardless of the rate of losing the packet.
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