Application-transparent Realization Of TCP Performance Optimization

The applications nowadays are more and more distributed and are mostly carried by IP network. The IP network always has some impairment, such as delay, jitter and packet loss, due to its best effort characteristic. Those network impairments will affect the performance of those distributed applications badly.The aim of this paper is to improve the capability of distributed applications when faced with network impairments by the application-transparent realization of TCP performance optimization and then hence to improve the performance of those applications. The paper studies TCP and its congestion control mechanism, the shortages TCP congestion control mechanism at protocol level still has nowdays, the necessity and possibility of application-transparent realization of TCP performance optimization. Then the paper discusses the techniques to achieve such optimization, including congestion window re-sizing, selective acknowledgement, data compression, packets coalescing and FEC (Forward Error Correction) at packets level. Besides, the paper also discusses how to deal with packets in Windows.The paper achieves packets capture, modification and forwarding by NDIS in Windows2003 Server environment. Based on the above, the paper accomplishes the application-transparent TCP performance optimization techniques and verfies the optimization result by testing. The paper further discusses the deficiency of the optimization work has been done, based on the testing results and the latest technology, and then points out those aspects to be improved in the next stage, which include processing capability improvement, data reduction based on data recognition, QoS, improvement at data compression and UDP support.The paper has comprehensively discussed the way and the mothods to achieve application-transparant TCP performance optimization and also how to capture, modify and transfer packets in Windows environment. These are referential. The testing results show that the work of the paper has achieved what has been expected at network delay and packet loss mitigation and can improve the application and response time remarkably.