Patent ID: 8473632

Claim:
A receiving apparatus that receives a plurality of fragmented packets from which a predetermined packet has been divided, comprising: a storage unit that stores a first checksum value corresponding to received data; a determination unit that determines, based on information contained in a header portion of a newly received fragmented packet, an overlap between the received data and data contained in the newly received fragmented packet; a reassembly unit that performs reassembly into the predetermined packet based on the plurality of received fragmented packets; a calculation unit that, before reception of the plurality of fragmented packets required for the reassembly into the predetermined packet by the reassembly unit is completed, calculates a second checksum value corresponding to the overlap and a third checksum value corresponding to the data contained in the newly received fragmented packet; and a control unit that stores, in the storage unit as a new checksum value, a value in which the third checksum value is added to a value in which the second checksum value is subtracted from the first checksum value.