LEO卫星环境下的SNACKTCP性能分析

An Experimental Study on the Performances of SNACKTCP in the LEO Satellite Networks

由于空间LEO(LowEarthOrbit)卫星通信网络受环境、通信链路、能源等诸多方面的制约,已经非常成熟的地面计算机网络协议在空间LEO卫星通信环境下是无法直接应用的.SNACKTCP(SelectiveNegativeAcknowl-edgmentTCP)是解决原有TCP不能适用于空间LEO卫星通信的改进方案,然而是否完全能在LEO卫星通信网络下应用还有待于进一步研究.作者在研究该改进协议的基础上进行NS2环境下的仿真模拟实验,比较分析了SNACKTCP和传统TCP的性能,还有针对性地进行了线路非对称模拟实验结果分析和链路误码率变化实验结果分析.证实了SNACKTCP在LEO卫星通信环境下的优良性能,并发现了其仍存在的问题,进而指出了实验的下一步研究方向.

LEO（Low Earth Orbit） satellite communication networks are of many constrictions, and generally, territorial communication protocols that have been consummated cannot be directly applied. Selective Negative Acknowledgment （SNACK） TCP is considered as the improved version of TCP to overcome these constraints. However, in the literature, there is no strong evi dence to show the applicability of SNACKTCP in such an exceptive environment. This paper presents intensive experiment results in NS2 to study the performances of SNACKTCP in the LEO satellite. In all tests, the authors compared the performance of SNACKTCP to that of conventional TCP. Two typical circumstances in LEO satellite networks, i. e. , asymmetric channels and the change about error-prone links are specifically observed and analyzed. While validating its excellent performance, a few problems existed in SNACKTCP are also found out in this paper.