面向卫星网络的TCP代理

当传统TCP协议用于卫星网络时面临各种问题,原因包括:卫星信道的高传输延迟、较大的误码率、带宽不对称、信号衰减等.为了提高卫星网络环境下TCP的性能,在不破坏TCP端到端特性的前提下,提出了一种新的主动代理方案.拥塞控制算法通过具有不同优先级的双报文对实施主动监测,能够根据网络带宽的变化自适应地调整TCP窗口.并且,对代理控制系统进行了稳定性分析.针对卫星网络下的TCP丢包恢复,提出了一种不依赖时钟同步的选择性否定应答算法.模拟实验表明,提出的TCP代理能够充分利用卫星网络的带宽,从而达到获得最佳有效吞吐率的目的.

TCP Proxy for Satellite Network

When used with satellite links, traditional TCP suffers from a number of performance problems, especially for higher propagation delay, bit error rate, asymmetrical bandwidth and signal attenuation due to rain. A new active proxy without breaking TCP semantic is proposed to improve TCP performance of satellite network. The congestion control algorithm in the proxy sets the window size according to the measurement information on bandwidth changes from the two probe packet pairs with different priorities. A stability analysis of the hybrid proxy system is performed. The loss recovery based on selective negative acknowledgement (SNACK) can work even if the clocks is not synchronized. The results demonstrate that proxy in combination with SNACK allows TCP to fully exploit the possible throughput of the satellite network.