Design And Implementation Of High BDP Network Acceleration Gateway

With the development of the Internet, networks with high bandwidth and delay(Bandwidthdelay Product) such as wireless network, high speed network and satel ite network are gradually becoming the mainstream networks. TCP/IP protocol no longer behaves excel ently in high bandwidth delay network as it does in conventional WAN in performance due to the intrinsic characteristics of the high bandwidth delay network. Thus basic data transmission and upper layer services are severely affected. Concerning this issue, an acceleration gateway system for high bandwidth delay network is designed and implemented to improve network transmission efficiency. Besides the support of transparent deployment, easier configurability and scalability, the obvious accelerating effect of this system is achieved.First, this thesis analyzes the specific performance problems faced with the high bandwidth delay networks, introduces WEB caching briefly and discusses the functional and performance requirements for the typical application scenario. Then this thesis utilizes TCP splitting to implement TCP transparent proxy, tests and compares different congestion avoidance algorithms, gives a method to tune the parameters of TCP protocol and implements data deduplication and compression for TCP stream. Next, this thesis discusses how to deploy the WEB cache proxy transparently as well as the cache and access control rules configuration for the proxy, and gives a layered deployment of the proxy to achieve connections reusing. Finally, this accelerating system is deployed in a particular high bandwidth delay network to test its accelerating effect.Utilizing protocol spoofing technique, the acceleration system deployed at the both sides of the high bandwidth delay link splits the TCP connections passed by into three sections, corresponding to three separated TCP connections. Connections between two accelerating gateways are ful y controlled, and to optimize those connections is to optimize the high bandwidth delay network. The tuning of the parameters and congestion avoidance algorithm of TCP protocol could accelerate the TCP transmission in double directions. Both the data deduplication and compression for TCP stream and caching mechanism for HTTP could reduce the amount of data transferred over the bottleneck link.The test results show that the transmission efficiency of high bandwidth delay network is significantly improved. The acceleration ratio of TCP can reach more than 1.5 times and HTTP access response time ratio can reach 10 times with the help of cache hit. Based on this thesis, many improvements for this system can be done and lots of optimization methods for other network protocols can be extended.