Based On Weighted Sampling Choke Fairness Congestion Control Mechanism Research Of The Algorithm

With the continuous expansion of the network scale and the emergence of a variety of new web services, Internet data traffic is increasing. Network congestion control has become an important mechanism for ensuring network performance and improving service quality. According to the characteristics of current network data flow, and considering the compatibility on the basis of the existing TCP stream, studying a congestion control method with scalability which is adapted to the development of integrated business from the network, has important application value and theoretical significance.This article firstly analyzes the causes of network congestion, and gives several ways to solve the congestion in the network. On this basis, it analyzes the current window flow control mechanisms from the main TCP protocol of transmission layer and the common queue management mechanisms. To counter that the original queue management algorithm can not achieve better network fairness, an improved algorithm for active queue management is proposed. Through some feedback standard, the paper points out that the current TCP control mechanism and queue management mechanism could not adapt to the increasing tendency of the current Internet media stream, and realize the fairness between UDP stream and TCP streamTo address the issue that non-adaptive flows, Including streaming media and multicast flow, squeeze too much network bandwidth, an active queue management algorithm based on weighted sample is made. Which partitions the queue from router, samples periodically, and composes candidate table for data flow, then matches the coming data packets in the candidate table, and punishes the hitted data flows according to the level of greed. The greed degree of data stream in the candidate table updates in real time based on the arrival data packets. The simulation results show that the active queue management mechanism can be used to punish the greedy flow well. In order to match the weighted sampling active queue management mechanism, a new congestion option is joined in the original transport-layer header, and congestion level is filled by intermediate routers and returned to the data sending source through ACK. The data sending source adjusts sending rate according to the congestion level, based on the regulating principle which tries to make TCP stream access to the same drop-rate with UDP flow of the same congestion levels after a penalty, and avoid excessive back-off. Simulation results indicate that the mechanism can enable TCP flow and UDP flow fair to enjoy bandwidth, besides, it provides compatibility with the traditional TCP stream, and dose not generate a new greedy flow.Finally, the paper summarizes the work that have done, and gives the prospect of the next study.