Research And Realization For Ethernet Physical Isolating Machine

The paper introduces some related knowledge on Ethernet physical isolating system and its Eight-channel design based on the embedded Ethernet technology, which adopts Ethernet switch to isolate two networks, supports 10BASE-T and 100BASE-TX, has good consideration of the system extensibility. Compared with physical isolating system based on the relay network switching, it has been greatly improved.The system is made up with one physical isolating controller and eight Ethernet terminals which be fitted in the user's computer. The controller is used to switch each channel's network, and the terminal is used to recognize the user's IC card, select one of two hard discs and send the user's information to the controller. And then the controller can make the choice of switching networks according to the identity.Physical isolating controller, which supports 10/100 Mbps, uses MCF5271 to be the processor, selects the corresponding channel via EPF10K30A, and controls eight KS8995MA chips to select network. The user's terminal uses C8051F226 as the controller, indentifies user's ID and rights in the SLE4442 card, selects one of two hard discs via EPM7064, and communicates with isolating controller via network interface chip RTL8019AS with the speed of 10Mbps.The system is used to isolate local network and public network, which needn't exchange data between two networks. As a experimental platform, the design scheme can be proved by software programming with it. It is important on the research of physical isolation technology and safe imformation exchange.The paper gives details on the background of the task, system scheme, system design, system test and so on, and the debug of its basic function has been fininshed.