The Development Of The Special Purpose Network Isolation Device Based On Embedded Technology

Network isolation technology is the key technology of data secure exchanging between the internal trusted network and the external untrusted network. Not only can it avoid the internal trusted network data leakage, but also resist the harmful attacks from the external untrusted network. Logical isolation technology makes the internal and external data exchange on condition, by making a special communication protocol and other security policies. The network isolation device we studied realized by the combination of dedicated isolation hardware and special communication protocol.The target of this thesis is to develop a network isolation device exclusively used in railway information system. This thesis has studied network isolation technology including embedded system, embedded GUI technology, embedded hardware principles, communication protocol design, and so on. Especially, the special network protocol of this topic is designed and implemented based on Linux network protocol stack and analysis of the process of formulating network protocol.This main work is listed as follows: 1. Analysing the environment where the special network isolation device is applied. And then get the functional requirements. 2. Comparing many kinds of embedded hardware and embedded system, then choose ARM+Linux based solution. 3. Designing the special communication protocol in a hierarchical thought based on Linux network protocol stack. 4. Implementing the network isolation device. 5. Developing a tool with a graphical interface for the users. 6. Building a test system and making a number of function testing and performance testing.