The Research Of Congestion Control Algorithm Based On TCP Protocol

With the continuous development of the Internet and computer technologies,the Internet has long been an indispensable part of people's production and life,and has profoundly affected the development and progress of human society.Especially in recent years,under the rapid development of e-commerce(mainly online shopping)and mobile internet,the requirements for network performance have become higher and higher.With the advent of big data and cloud computing era,the transmission of data will increase network congestion.It can cause problems such as increased transmission delay,increased packet loss rate,and reduced throughput in the link.Severely can also cause the network to crash.Therefore,the problem of network congestion has become a hot topic in current network communication protocols.The problem of network congestion not only concerns the people's yearning for high quality of life,but also reflects the current state of development in society and has far-reaching practical significance.This paper first briefly introduces the current research status of the current congestion protocol algorithm,and leads to significant improvements in the congestion control mechanism.Details the three-way handshake and four-way breakup of the TCP protocol when creating and disconnecting connections.While introducing the concept of TCP congestion control,it discusses the specific causes of congestion.Several execution processes of the traditional congestion control algorithm are analyzed,including: slow start,congestion avoidance,fast retransmission,fast recovery and so on.Explained the data in the network transmission process,which stages are prone to network congestion,what measures should be taken to deal with.In addition,Description of the data transfer process of the Sliding Window Protocol.Then the congestion control algorithm based on delay and packet loss is described and analyzed,and the defects of these two algorithms are explained in detail.This article summarizes the measurement scheme and correlation estimation algorithm based on RTT,and proposes a specific research direction based on related background.Firstly,the advantages and disadvantages of the TCPW algorithm are studied and analyzed.Based on this,the improved algorithm NEWTCPW is proposed.The algorithm effectively improves the evaluation scheme of RTT,and predicts the round-trip RTT value through weighted average expression and timeout retransmission mechanism.Then,according to the calculated value,the congestion level is divided in detail to distinguish between congestion loss and wireless loss.After briefly introducing the construction of the NS2 simulation platform and the detailed simulation flow,the implementation of the improved algorithm is explained in detail.Then the improved algorithm and other algorithms were simulated and the simulation results were compared and analyzed.After comprehensive analysis of the Vegas and Vegas-A algorithms,I discovered that they have some problems in the slow start and congestion avoidance phases.Aiming at various defects in the algorithm,this paper presents an improved algorithm NewVegas.In the slow start phase,the congestion window is mainly improved,and the cwnd is increased by a rate between the linear increase and the exponential increase method,which is called the stability increase of the congestion window.In the congestion avoidance phase,the congestion window is determined by analyzing the correlation between the expected throughput and the actual throughput difference and the two constant values ? and ? of Vegas.Finally,simulation experiments are conducted to analyze the performance of the improved algorithm and other algorithms in high and low bandwidth networks.