基于改进慢启动算法的大文件快速传输

针对传统TCP在当前网络环境下传输大文件性能较低的问题，对TCP传输协议中的慢启动算法部分进行了相应的研究与优化。根据标准慢启动算法存在的问题并结合高速网络以及大文件传输的性能特点，提出了一个具有网络状态感知能力的慢启动改进算法。改进算法主要优化了TCP拥塞窗口的增长策略，它实时地监测文件在传输过程中TCP报文段的往返时间（RTT），并根据RTT的变化情况采用不同的窗口增长方式更新拥塞窗口；将改进算法部署在Linux网络模块中并分别在模拟网络环境和实际网络中进行测试。实验结果显示，改进算法能使发送窗口一直保持在一个较高的水平，实际数据传输速率和吞吐量均有了明显的提高。

Large file transfer based on improved slow start algorithm

In view of the low performance of traditional TCP protocol in transmitting large files in the current network environment, this paper studied and optimized the slow start algorithm of TCP transport protocol. According to the problems of standard slow-start algorithm and the performance characteristics of high-speed network and large file transmission, this paper proposed an improved slow-start algorithm with network state awareness. The improved algorithm mainly optimized the growth strategy of TCP congestion window, which monitored the round-trip time(RTT) of TCP packets in real-time during the transmission process, and updated the congestion window with different window growth methods according to the changes of RTT. It deployed the improved algorithm in the Linux network module and tested it in the simulated network environment and the actual network. Experimental results show that the improved algorithm can keep the sending window at a higher level, and the actual data transmission rate and throughput have been significantly improved.