The Testing Method Research Of IEC60870-5-104Communication Protocol Based On Network Monitoring Mode

Communication protocols are the soul of the computer networks andcommunication systems. The protocol testing plays a vital role in ensuring thecorrectness of the implementation of protocols. As computer network andcommunication technologies are developing rapidly, the network scale iscontinually expanding and the possibility of problems is also on the increase.The kinds and quantity of communication protocols are more and more, andthen the protocol design, development and implementation is becoming morecomplex.Therefore, the protocol testing technology presents a great challenge.The traditional active testing method completes protocol testing by simulatingcommunication, that generally needs to be separated from the actual networkand can not reflect the real working condition of the protocols. The emergingpassive testing method using another test idea, collects data through networkmonitoring, and then analyzes the data to discover the existing problems anderrors in the implementation of protocols. Monitoring test does not disturb thenormal communication process, that is of real-time nature and especiallysuitable for the testing and analysis of running network protocols.In this paper, we research the testing methods of IEC60870-5-104 communication protocol based on TCP/IP through network monitoring andcomplete simulation experiment to verify the feasibility of testing methods bymonitoring tool Winpcap and Visual C++. The main tasks in this paper are asfollows.1. First, we solve network raw packet capture and master programmingmethods and API functions of monitoring tool Winpcap.2. We study the contents and methods of TCP/IP protocol raw packetprocessing，propose a simple and fast algorithm of TCP session user datareassembly and compare this algorithm with some other ones.3. We research IEC60870-5-104communication protocol based onTCP/IP protocols and then present the monitoring test methods of thisprotocol, mainly including APDU packet parsing, link timeout and slidingwindow error detection, IEC60870-5-104application process error detection.Finally, compare the listening methods with those of some other protocols.4. On the basis of the above research and testing methods, we completethe simulation of monitoring testing IEC60870-5-104protocol by Winpcapand analyze the results achieved.The testing results achieved prove that the proposed testing methods ofIEC60870-5-104communication protocol based on network monitoring modeare feasible, and basically meet testing requirements.