高速网络中TCP拥塞控制研究
发布时间：2018-08-05 19:21
【摘要】：作为一种非常重要的传输层协议以及网络中端到端拥塞控制的主要组成部分,TCP在各种网络环境中的性能一直以来都受到广泛关注。TCP的性能主要是由其拥塞控制算法决定的。与此同时如今具有大的时延带宽积的高速网络正在随着技术的进步而逐渐出现并被应用于实际的生产和生活环境中。近些年来,针对这样的网络,有很多的拥塞控制算法被提出来用以改进TCP的性能。本文研究了高速网络上TCP拥塞控制算法,主要包括以下的三部分工作：提出一种新的TCP拥塞控制算法、利用NS-2仿真平台验证算法性能以及在Linux系统上实现并在实际的网络中测试。 现如今的网络中有很多不同类型的高速TCP拥塞控制算法,可以大致分成基于丢包、基于延迟以及前两者的混合这三种类型。但是其中基于丢包的这些高速的TCP协议存在潜在的对于已经在网络中广泛应用的Reno的不公平性,这会严重的损害在同一条瓶颈链路上Reno的吞吐量。另一方面,纯粹的基于延迟的流在和基于丢包的流的竞争中没有优势。在本文中,我们提出了一种基于控制论的新的混合的TCP拥塞控制算法：Hybrid High Speed-TCP(HHS-TCP)。它是一种基于丢包和基于延迟思想的协同方法。HHS-TCP的发送速度由两种不同的机制共同决定。新算法能够在当链路的带宽没有得到充分利用时快速增长发送速度,当瓶颈链路排队延迟增大则减小发送速率。HHS-TCP提供了良好的带宽利用率的扩展性,同时也能提供较好友好性。 为了验证我们提出的新算法的性能,作者使用了NS-2仿真平台做了较为全面的测试。通过对随机丢包链路单个流的吞吐量以及分别在Drop-tail和RED两种不同的路由策略下多个流的吞吐量的测量,可以看出HHS-TCP的带宽利用率更高；同时通过比较不同类型的高速TCP协议与Reno之间在同一条瓶颈链路共同竞争时的吞吐量的比例,看出混合型的HHS-TCP能够取得较好的公平性。此外为了能够在实际的网络中测试新算法的性能以及应用到实际的网络业务中,在分析了Linux中TCP协议栈结构的基础上,我们将新算法在Linux系统中以模块化的形式实现,方便加载和删除。在实际的局域网中使用新的模块进行文件传输的测量,结果显示新算法能够比之前的协议提高10%-15%左右。 本文的主要贡献和创新有：本文通过研究网络中的拥塞问题以及TCP中的拥塞控制算法,分析了拥塞产生的原因以及对拥塞控制算法的评价方法,提出了一种新的基于混合机制的拥塞控制算法,该算法能在高速网络中获取高的带宽利用率的同时保持对传统TCP协议的公平性。同时我们将新算法通过模块化的方式在Linux系统中加以实现,实际测试显示新算法具有一定的实用价值。
[Abstract]:As a very important transport layer protocol and the main component of end-to-end congestion control in the network, the performance of TCP in various network environments has been widely concerned. The performance of TCP is mainly determined by its congestion control algorithm. At the same time, the high speed network with large delay bandwidth product is emerging gradually with the development of technology and applied to the actual production and living environment. In recent years, many congestion control algorithms have been proposed to improve the performance of TCP. In this paper, the TCP congestion control algorithm in high-speed networks is studied, which includes the following three parts: a new TCP congestion control algorithm is proposed. The NS-2 simulation platform is used to verify the performance of the algorithm, and the algorithm is implemented on the Linux system and tested in the actual network. Nowadays, there are many different types of high-speed TCP congestion control algorithms in networks, which can be divided into three types: loss of packet, delay and mixing of the first two. However, these high-speed TCP protocols based on packet loss have potential unfairness to the Reno which has been widely used in the network, which will seriously damage the throughput of Reno on the same bottleneck link. On the other hand, pure delay-based flows have no advantage over packet-based flows. In this paper, we propose a new hybrid TCP congestion control algorithm named: hybrid High Speed-TCP (HHS-TCP) based on cybernetics. It is a cooperative method based on packet loss and delay. The transmission speed of HHS-TCP is determined by two different mechanisms. The new algorithm can rapidly increase the transmission speed when the bandwidth of the link is not fully utilized, and reduce the transmission rate. HHS-TCP provides a good scalability of bandwidth utilization and good friendliness when the bottleneck link queue delay increases. In order to verify the performance of the proposed new algorithm, the author has made a more comprehensive test using the NS-2 simulation platform. By measuring the throughput of a single stream in a random packet loss link and the throughput of multiple streams under two different routing strategies of Drop-tail and RED, we can see that the bandwidth utilization of HHS-TCP is higher. At the same time, by comparing the ratio of throughput between different types of high-speed TCP protocols and Reno in the same bottleneck link competition, we can see that hybrid HHS-TCP can achieve better fairness. In addition, in order to test the performance of the new algorithm in the actual network and to apply it to the actual network service, on the basis of analyzing the TCP protocol stack structure in Linux, we implement the new algorithm in the Linux system in the form of modularization. Easy to load and delete. In the actual LAN, the new module is used to measure the file transfer. The results show that the new algorithm can increase the accuracy by about 10% to 15% compared with the previous protocol. The main contributions and innovations of this paper are as follows: by studying the congestion problem in the network and the congestion control algorithm in TCP, the causes of congestion and the evaluation method of congestion control algorithm are analyzed. A new congestion control algorithm based on hybrid mechanism is proposed, which can achieve high bandwidth utilization in high-speed networks while maintaining fairness to traditional TCP protocols. At the same time, we implement the new algorithm in Linux system by modularization. The practical test shows that the new algorithm has some practical value.
【学位授予单位】：北京邮电大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP393.04
本文编号：2166752
[Abstract]:As a very important transport layer protocol and the main component of end-to-end congestion control in the network, the performance of TCP in various network environments has been widely concerned. The performance of TCP is mainly determined by its congestion control algorithm. At the same time, the high speed network with large delay bandwidth product is emerging gradually with the development of technology and applied to the actual production and living environment. In recent years, many congestion control algorithms have been proposed to improve the performance of TCP. In this paper, the TCP congestion control algorithm in high-speed networks is studied, which includes the following three parts: a new TCP congestion control algorithm is proposed. The NS-2 simulation platform is used to verify the performance of the algorithm, and the algorithm is implemented on the Linux system and tested in the actual network. Nowadays, there are many different types of high-speed TCP congestion control algorithms in networks, which can be divided into three types: loss of packet, delay and mixing of the first two. However, these high-speed TCP protocols based on packet loss have potential unfairness to the Reno which has been widely used in the network, which will seriously damage the throughput of Reno on the same bottleneck link. On the other hand, pure delay-based flows have no advantage over packet-based flows. In this paper, we propose a new hybrid TCP congestion control algorithm named: hybrid High Speed-TCP (HHS-TCP) based on cybernetics. It is a cooperative method based on packet loss and delay. The transmission speed of HHS-TCP is determined by two different mechanisms. The new algorithm can rapidly increase the transmission speed when the bandwidth of the link is not fully utilized, and reduce the transmission rate. HHS-TCP provides a good scalability of bandwidth utilization and good friendliness when the bottleneck link queue delay increases. In order to verify the performance of the proposed new algorithm, the author has made a more comprehensive test using the NS-2 simulation platform. By measuring the throughput of a single stream in a random packet loss link and the throughput of multiple streams under two different routing strategies of Drop-tail and RED, we can see that the bandwidth utilization of HHS-TCP is higher. At the same time, by comparing the ratio of throughput between different types of high-speed TCP protocols and Reno in the same bottleneck link competition, we can see that hybrid HHS-TCP can achieve better fairness. In addition, in order to test the performance of the new algorithm in the actual network and to apply it to the actual network service, on the basis of analyzing the TCP protocol stack structure in Linux, we implement the new algorithm in the Linux system in the form of modularization. Easy to load and delete. In the actual LAN, the new module is used to measure the file transfer. The results show that the new algorithm can increase the accuracy by about 10% to 15% compared with the previous protocol. The main contributions and innovations of this paper are as follows: by studying the congestion problem in the network and the congestion control algorithm in TCP, the causes of congestion and the evaluation method of congestion control algorithm are analyzed. A new congestion control algorithm based on hybrid mechanism is proposed, which can achieve high bandwidth utilization in high-speed networks while maintaining fairness to traditional TCP protocols. At the same time, we implement the new algorithm in Linux system by modularization. The practical test shows that the new algorithm has some practical value.
【学位授予单位】：北京邮电大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP393.04
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2 于梅尔·哈克;;奥巴马团队战斗规则[J];商界(评论);2009年02期
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