Research And Implimentation Of VPN Client Based On WinCE

While wireless access has experienced a rapid growth in recently years, people no longer satisfied with just the Internet through cable lines, but hope to wirelessly access The handheld mobile devices such as PDA has a rapid growth in volume,more and more people use them in their daily life.For enterprise users,access to corporate resources through handheld devices is not safe.VPN based on embedded system could fundamentally solve the security issues.Windows CE is an embedded real-time operating system, and is a version of Windows operating system in the embedded device. Because its easy-to-use, powerful, it widely used in smart phone PDA ect. So we using WinCE operating system to achieve VPN client.This paper deeply analyses the popular VPN system on Windows, which based on the middle layer technology to deal with packets. Because of the limitations of embedded devices, such as limited resources, a slow speed of CPU, we can not achieve the VPN client in this way in embedded systems.Aim at embedded device's characteristic, Design and Implement one kind new based on virtual Network card technology. Through virtual network card data packets are submitted to the application layer for IPSec processing, And it can improve the encryption processing speed by calling SD card.This paper deeply analyses the architecture and message processing of the VPN client.It also foucus on the achievement of the virtual card and IPSec module.Through test, the results show that the latency and throughput have been affected, but it can meet the basic application requirements of embedded devices.