Design And Implementation Of Simplex Communication Isolation System Based On Digital Voice Board

With rapid development of modern information technology, various information systems have becoming indispensable for our daily life. There are more and more data be exchanged between Intranet and Internet, and at the same time, network security is becoming even more important for building an information system. Some security risks have emerged since the traditional network security technology could only provide limited safeguard for the data exchange.Therefore, to realize the technology which can provide a safe, reliable, quick and real-time data exchange in the condition of information isolation is becoming one of hot subjects both at home and abroad. This article will introduce a simplex communication isolation system based on digital voice board which was designed according to the requirements both of communication isolation and security data-exchange. The system realizes data flow from low-class internet to high-class intranet and at the same time, prohibits data flow from high-class intranet to low-class internet. Through this system, internet gateway server will realize real time data collection and transmit data to intranet quicker and more accurate, which not only improve the work efficiency of intranet but also guarantee it's security.Here are the summaries:1) Introduce the status of today's Internet security and safeguard technology, analyze the essential and development of Internet isolation technology and study the characteristics and requirements of simplex communication.2) Design a system structure of simplex communication system to meet the requirements of system function. In this part, I will describe its hardware and software structure, and more, I will give an introduction to the functions of its simplex isolation, communication control, configuration management, security certification and log audit modules.3) Based on the HSD-240D digital voice board used in this system, this part will introduce the data-exchange process in simplex isolation module, data frame and the way of communication. In addition, size of data cache, process of DSP data-exchange, definition of transmission line and port line will also be introduced.The system is designed to ensure the security and reliability of the simplex communication from the sides of both hardware and software.4) Introduction of communication protocol in each layer of transmission control module like link layer, network layer, transmission layer and application layer with reference to TCP/IP protocol. In this part, programs regarding data sending and receiving in transmission ends will be introduced. Examples of key program which provide the transmission strategies and retransmission control technologies to solve security problems will be given.5) Build a test system to test the functionality, reliability and unidirection of original system. Test result shows that the test system meet the requirement of"flowing in without flowing out"by the simplex isolation system.