TCP在移动环境下的性能及其改善

The TCP's Capability and It's Improvement at the Environment of Moving

TCP(传输控制协议)是在有线环境下设计并调整改善的第四层协议。但在移动环境中它的端到端性能有所下降。近年来,有很多新的协议提出用以提高移动环境下TCP 的性能。其中大多数协议需要一个中间节点来参与TCP连接,这一点影响了TCP的端到端性能。TCP HACK和 Freeze TCP是最近提出的两种真正的端到端协议。本文分析了将来TCP的发展方向并比较了现在已有解决方案的优缺点。

Transmission control protocol (TCP) has been designed and tuned as a reliable transfer protocol forwired links. However, it incurs end-to-end performance degradation in mobileenvironments. Recentyears, many protocols have been proposed to enhance the performance of TCP in mobile environments. Although these methods simulate better than original TCP, but they either need an intermediary (such as the base station) to modify TCP or cannot perform well in the situations where both high bit errorrates and disconnections happen. In this article, we propose a protocol named adaptive TCP, which is a combination of TCP HACK (Header Checksum Option) and Freeze-TCP mechanisms but both have been modified to make them work more efficiently. By using the adaptive TCP, we can get a true end-to- end TCP and offer quality of service for the performance of TCP in mobile environments where both high bit error rates and disconnections occur.