Research Of Fairness Of TCP-BBR Algorithm In Wireless Network

With the development,popularization and application of the Internet of Things,wireless networks and Vehicular Ad-hoc Network(VANET),massive and multi-type data are generated in the network,and the information in the network is exploding.In the emerging field of vehicle-mounted self-organizing networks,there is a high demand for network service quality.When the link in the network is congested,the number of data packages in a certain part of the link will be excessive,which will cause the performance of some part or even the entire network to degrade.In severe cases,it may even cause the network to collapse.Therefore,an effective congestion control algorithm must be designed to ensure the normal operation of the network.Google has proposed TCP-BBR(Bottleneck Bandwidth and Round-trip Propagation Time).In terms of link awareness and response time,the performance of the TCP-BBR algorithm on the long fat pipe is superior to the traditional TCP protocol.However,the BBR algorithm also has certain problems.The BBR algorithm cannot achieve fairness with other congestion control algorithms.When the BBR algorithm flows compete with other congestion control algorithm flows for bottleneck bandwidth,BBR flows occupy more bandwidth resources.When the data flows of the long round-trip delay of the BBR algorithm competes with the data flows of the BBR short round-trip delay,the data flows of the long round-trip delay occupie more bandwidth resources.Therefore,the fairness of the BBR algorithm in the wireless network is the focus of the work.The BBR algorithm cannot achieve a fair allocation of channel resources.In order to improve the fairness between the TCP-BBR congestion control algorithm and the delay-based congestion control algorithm,a TCP-BBR-based congestion control algorithm(MFBBR)with moderate fairness is proposed.In order to improve the internal fairness of the BBR algorithm,a fairness improved BBR congestion control algorithm(RFBBR)is proposed.This paper verified the fairness performance between the TCP-BBR congestion control algorithm and the TCP-Westwood algorithm and the fairness performance of BBR algorithm between different RTT data flows through the simulation experiments on the Mininet emulator in the 4.9 kernel of the Ubuntu system,and proposed MFBBR algorithm and RFBBR algorithm.Simulation results show that the improved algorithm can ensure higher throughput in avoiding channel congestion while ensuring the fairness of the algorithm,and meet the fairness requirements of the congestion control algorithm.