A communication control system and a method of implementing a high-speed data transmitting and receiving process uses a communication protocol program, a protocol buffer which is managed by the communication protocol program, a communication controller for controlling a transmission line and a network buffer managed by the communication controller. Further, there is provided a shared-buffer which is shared by the protocol buffer and a communication buffer. Frame data from a transmission line is shared by the shared-buffer, so that the frame data is directly written to and read from the shared-buffer by means of a shared-buffer control. Since the buffer is shared between the transmission line and the protocol, no excessive movement of data is required, thereby improving the throughput of the communication system as a whole.