Research On TCP Incast In Data Center Network

With cloud computing technology continues to be mature, the Data Center is also developing well. Data Center Network has its own unique workload,speed and size,when using the TCP protocol in data center environments,TCP Incast problem comes out,it is a congestion problem.Due to the congestion problem,the performance of the data center network is greatly affected.Therefore,how to effectively solve the problem is an important topic that has practical application value.This thesis briefly introduces the TCP Incast, and analyzes the causing reasons of this problem.The researchers at home and abroad have put forward a variety of solutions,these solutions are introduced in detail in this thesis.All these solutions in certain cases, can effectively solve the congestion problem, but have not fundamentally solve the problem.Then this thesis analyses the present two TCP Incast model in detail, namely TCP Incast model for pipe and TCP Incast model for data block, this thesis expounds the advantages and disadvantages of the two models,from the TCP version, realization method and experiment, and many other aspects. Through learning these models can further understanding the problem.This thesis researches the solution of reducing the minimum retransmission counter,based on retransmission timeout optimization algorithm can be more reasonable to alleviate TCP Incast problem, and this thesis verified the optimization algorithm.Removing the delay ACK can influence this solution, and then verified by experiment in our own environment. When the minimum retransmission counter is reduced to less than the time of delay confirmation, there will be a timeout redundant phenomenon, In this case closing the delay ACK mechanism can improve throughput.This thesis researches TCP congestion control algorithm, and puts forward the improved TCP protocol based on the data center network environment.The improved protocol adopts showed congestion, and 2 bits identify four congestion level, this protocol uses congestion control method to adjust the sending rate.Then this thesis verified the effectiveness of the algorithm of the transport layer in our environment,it can effectively alleviate the TCP Incast problem.