基于正向时延的卫星网络拥塞控制算法研究  

Research on Congestion Control Algorithm of Satellite Network Based on Forword Direction Delay

作　　者：关世杰[1] 姜月秋[1] 关启学[1] 郭秦超 GUAN Shi-jie;JIANG Yue-qiu;GUAN Qi-xue;GUO Qin-chao(College of Information Science and Engineering, Shenyang Ligong University, Shenyang 110159, Liaoning, China)

机构地区：[1]沈阳理工大学信息科学与工程学院,辽宁沈阳110159

出　　处：《兵工学报》2018年第5期945-951,共7页Acta Armamentarii

基　　金：国家自然科学基金项目(61501307;61471247);辽宁特聘教授资助项目(2016年);辽宁省高等学校优秀人才支持计划项目(LR2015057);辽宁省"百千万人才工程"培养经费资助项目(2014921044);辽宁省教育厅科学研究一般项目(L2015380);沈阳理工大学重点学科开放基金项目(4771004kfx24);沈阳理工大学博士后科研启动基金项目(2016年)

摘　　要：在具有带宽不对称特点的卫星网络中,反向(地对空)链路带宽较小,更容易发生拥塞。当反向链路发生拥塞时,可以通过减小发送端的发送窗口来降低拥塞,但是这也降低了网络正向(空对地)链路的吞吐率。针对以上问题,提出了基于正向时延的TCP Vegas正向拥塞控制(Vegas_FD)算法。该算法通过测量数据分组的正向延迟时间,判定通信链路是否发生拥塞,并根据通信链路不同的拥塞类型采取不同的控制策略,使拥塞控制算法在反向链路发生拥塞时仍保持较高的吞吐率,适应了卫星网络带宽不对称特性。基于网络仿真软件Opnet进行了实验,结果表明,在卫星网络中Vegas_FD算法比Vegas算法、Westwood算法吞吐率性能明显提高,验证了该算法的有效性。In satellite networks featuring asymmetric bandwidth, the bandwidth of reverse （earth-to-satel- lite） links is narrow, and congestion is more likely to occur in these links. Congestion occurring in a re- verse link is alleviated by decreasing the send window at the sending end, during which, however, the throughput of forward （satellite-to-earth） links in the network is also lowered. Vegas_FD, a TCP Vegas forward congestion control algorithm based on forward direction delay, is proposed so as to tackle the fore- going problems. The proposed algorithm judges whether a communication link is congested or not by measuring the forward direction delay time of data packets, and adopts different control strategies as per different congestion types of the communication link, so as to ensure that the congestion control algorithm could keep a high throughput when the reverse link is congested. With these functions, the algorithm is adapted to the asymmetry of the satellite network＇ s bandwidth. The simulated results based on Opnet software show that Vegas_FD algorithm is used to improve remarkably the throughput in satellite networks compared to Vegas and Westwood algorithms.

关 键 词：卫星网络 拥塞控制 空间通信协议规范传输协议 TCP Vegas算法 

分 类 号：TN927.21[电子电信—通信与信息系统]