Patent ID: 8014287

Claim:
A communications apparatus which notifies a communications counterpart apparatus connected via a network of a data amount in a window size, and receives data as large as the window size, the data being transmitted from the communications counterpart apparatus, said communications apparatus comprising: a storing unit for storing the data transmitted from the communications counterpart apparatus; a size notifying unit configured to notify the communications counterpart apparatus of the window size, the window size being larger than a capacity of said storing unit; a receiving unit configured to (i) sequentially receive a plurality of data packets, the plurality of data packets being the data as large as the window size and being transmitted from the communications counterpart apparatus and (ii) store the received plurality of data packets in said storing unit, the plurality of data packets being transmitted according to the window size notified by said size notifying unit; a processing unit configured to retrieve and process the plurality of data packets stored in said storing unit; a discarding unit configured to secure available space in said storing unit by discarding a data packet included in the plurality of the data packets stored in said storing unit; and a retransmission requesting unit configured to request the communications counterpart apparatus to retransmit the data packet discarded by said discarding unit, and wherein said discarding unit is configured to discard, as the discarded data packet, a data packet other than a last packet so that a last data packet transmitted from the communications counterpart apparatus is stored in said storing unit as the last packet, the last data packet being one of the data packets sequentially transmitted in accordance with the window size notified by said size notifying unit.