Design And Implementation Of The TCP Transparent Proxy With Data Compressing In WAN

Currently,the widely used proxy server is lacking in the characteristics of special use,easy operation and application applicability. Proxy server tends to play a role in packets filtering or network isolation. Users need to command the knowledge of how to configure their PC in order to get benefit from the use of a proxy server which functions as a firewall, which raises the threshold of using it. Additionally, the proxy server is working at session layer based on ISO , so it has a big limitation in diverse applications transplant. Most proxy servers, nowadays, are used to provide Web service proxy.Due to the deficiencies formulated above and the increasing demand of high quality network service, the article introduce the concept and design of TCP transparent proxy in TCP overlay network, combined with DRE(Data Redundency Elimination), a method of data compressing in WAN. Maitainning the normal fuction of firewall, the TCP transparent proxy with DRE can further handle the TCP network packets in order to shorten the transmission delay and relieve the pressure of network congestion. The article researches on the function of TCP transparent proxy based on three back-to-back TCP connections, memory management and flow control. In details, the article formulates how to design the key modules in the form of thread and the prossesing flow of these modules. The key techniques used in the design of TCP transparent proxy are also detailed. The method of TCP transparent proxy is tested in laboratory that provides a virtual environment of WAN. Three parameters, which is tansmission rate, compressing rate and remained space of buffer pool, are observed during the test.The result of test comes to conclusion that TCP transparent proxy with DRE can reconcile the contradiction between processing time and transmission delay and tansmission rate is raised with the update of data dictionary.