PURPOSE: To perform the data transfer processing with the optimum efficiency according to the environmental condition at the time, in a communication control system to be connected with plural kinds of LAN.
CONSTITUTION: In a communication control system which is connected with plural kinds of LAN and performs the data transfer processing by a transmission confirmation protocol (TCP/IP, etc.,), a buffer control part 1014 and a transmission/reception buffer size table 1015 are provided. In the transmission/ reception buffer size table 1015, the value of the corresponding transmission/ reception buffer size for each of various kinds of environmental conditions (maximum transfer amount of the transmission medium of the LAN, the classification and transmission rate of the LAN and the classification of the user application accompanying a data transfer and a transmission data size, etc.) in a data transfer processing is preliminarily defined. The buffer control part 1014 discriminates the environmental condition when a data transfer processing is started and sets the transmission/reception size corresponding to the environmental condition based on the buffer size table 1015.
YASUE RIICHI
GOTOU NORIHIRO
