Abstract: A communication control processor at a transmission side add a path control information area to a TCP data area of data acquired from an application, saves the destination address, and selects a pair of addresses of the transmission communication adapter and the reception communication adapter in consideration of the condition of the path and the number of connections to send the data. A communication control processor at the reception side stores the destination IP address stored in the path control information into the destination IP storing area, deletes the path control information area added to the TCP data area by the transmission side, and passes the data to an application when the address of the own communication adapter is set in the destination IP storing area in the received data.