Patent ID: 7180896

Claim:
A packet retransmission system which includes a transmission apparatus for transmitting a packet with an added sequence number, a reception apparatus connected to the transmission apparatus through a network, and a request application unit connected to the reception apparatus, for retransmitting the packet with the added sequence number between the transmission apparatus and the reception apparatus in response to a loss of the packet in packet transmission, the transmission apparatus comprising: a retransmission buffer for storing one or more packets, which have been transmitted to the reception apparatus; retransmission-request receiving means for identifying the sequence number and a latest sequence number provided to the request application unit, in a retransmission-request packet received from the reception apparatus, and notifying the sequence number and the latest sequence number; retransmission packet detecting means for detecting whether a notified sequence number exists in the retransmission buffer, retransmission buffer deleting means for comparing the sequence numbers of the packets stored in the retransmission buffer to the latest sequence number notified by the retransmission-request receiving means, and deleting packets from the retransmission buffer based on the comparison; and retransmission means for retransmitting all packets detected by the retransmission packet detecting means to the reception apparatus.