A New TCP Congestion Control for Ultra High Speed Data Transfer Applications

为了在占用整个网络带宽的Gbps级Internet骨干网上实现高速的TCP通信，本研究项目研究了一种新的拥塞控制方案。它在一个TCP连接中引入多个子连接，并使用拥塞窗口进行拥塞控制，而不是将拥塞窗口作为一个整体来执行。在这两年中，我们做了以下研究工作：1.设计了一种新的TCP拥塞控制算法基于上述考虑，研究了一种新的算法。2.算法的评估在网络模拟器ns-2上开发了算法的评估仿真软件，并进行了性能评估。3.算法的改进及其评估性能不佳的原因似乎是算法在重传过程中过于急切。因此，对算法进行了修改和重新评估。但是，虽然拥塞程度得到了改善，但吞吐量与第一种算法相似。4.第三种算法的设计为了解决这两个问题，设计了第三种算法。

For realizing high speed TCP communication over Gbps class Internet backbone, which occupies the whole bandwidth of the network by itself, this research project studied a new congestion control scheme. It introduces multiple subconnections in a TCP connection and the congestion control using congestion window is performed by individual subconnections instead of TCP connection as a whole. As a result, it is expected that there are a number of conventional TCP connections even in the situation where there are only a small number of high speed TCP connections.The following research activities are done in these two years.1.Design of a new TCP congestion control algorithmBased on the consideration mentioned above, a new algorithm was studied.2.Evaluation of designed algorithmThe evaluation simulation software for the algorithm was developed on the network simulator ns-2,and the performance evaluation was done. But, a good result was not obtained.3.Modification of the algorithm and its evaluationThe reason of the bad performance seemed to be the algorithm was too eager in the retransmission. So, the algorithm was modified and re-evaluated. But, although the level of congestion was improved, the throughput was similar to the first algorithm.4.Design of the third algorithmIn order to resolve those two problems, the third algorithm was designed.