A communication apparatus extracts segment data including information defining the position of a fragment packet before fragmentation and the identification information of the fragment packet from the header information of the fragment packet. If the fragment packet is the last fragment packet, the apparatus extracts packet length information before packet fragmentation from the header information of the last fragment packet. A memory stores a segment database holding segment data and information associating identification information with packet length information. The communication apparatus executes integration processing of the segment data based on information stored in the segment database and determines whether the reception of all the fragment packets constituting the packet before fragmentation is complete.