The problems that arise while developing a real-time distributed information-processing software system are studied. And based on the TCP/IP protocols and socket, for its facility in client/server (C/S) model networking programming, a prototype is designed for data transmission between the server and clients and it is applied on an on-line products automatic detection system. The probability analysis on network congestion was also made. A proper mechanism based on the ARCC (adapted RTT congestion control) algorithm is employed for detecting and resolving congestion, the purpose of which is mainly to achieve congestion avoidance under the particular conditions in this network-based system and reach the desired performance. Furthermore, a method is proposed for a client to diagnose automatically the connection status between the server and the client and to re-connect to the server when the disconnection is detected.