Research On C Oupled Multi-Flow Congestion Control Technology Based On Delay Guarantee

With the development of the network,the unprecedented growth of network traffic has greatly increased the load of the current network,resulting in a series of problems,such as link congestion and even packet loss.At the same time,business requirements for service quality are more diverse.For example,many real-time services require not only high throughput,but also low latency.However,simply increasing the link capacity cannot fundamentally solve the above problems and satisfy the service requirements.Therefore,it is necessary to design a new congestion control method to meet the diverse requirements of different services for service quality on the basis of reducing network congestion or packet loss.Aiming at the performance index of delay,this paper proposes a coupled multi-flow congestion control mechanism based on delay guarantee.The main work includes: 1)An available bandwidth detection algorithm on bottleneck links is proposed to reduce the queuing delay.First locate the bottleneck link in the network,and couple the shared bottleneck flow on the bottleneck link as a shared bottleneck flow group;then gradually increase the congestion control window of the shared bottleneck flow group,so that make the total transmission rate on the bottleneck link approach the bottleneck link bandwidth.The bottleneck link bandwidth that does not generate queues,and the available bandwidth of the shared bottleneck flow group is measured and calculated according to the bottleneck link bandwidth;2)By studying the existing link resource allocation algorithms,an algorithm of available bandwidth allocation with guaranteed transmission delay is proposed.The algorithm preferentially allocates link bandwidth for real-time services with time delay requirements,which satisfies the basic communication requirements of these services,and then allocates the remaining bandwidth to other services based on utility function fairness,realizing the fairness of bandwidth allocation,then adjust the congestion control window of each shared bottleneck flow based on the bandwidth allocation result.In addition,the redundant bandwidth is calculated and re-allocated according to the duty cycle of each service flow to further improve the bandwidth utilization rate;3)In order to realize the above algorithm,a coupled multi-flow congestion control system is designed.The system divides the above algorithm into two modules: data transmission and network control.The two modules cooperate with each other to realize the coupled multi-flow congestion control mechanism based on delay guarantee.Finally,this paper uses the above method to design the corresponding functional modules on the NS3 simulation platform,simulates the improved coupled multi-flow congestion control mechanism based on delay guarantee.The analysis the simulation results verifies the feasibility of the scheme.