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A Kind Of ODE Model For TCP/AQM In Network Traffic

Posted on:2022-02-21Degree:MasterType:Thesis
Country:ChinaCandidate:YASIR AKHTARFull Text:PDF
GTID:2518306728969189Subject:Applied Mathematics
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The primary purpose of the Active queue management(AQM)router is to control the network congestion by packets of marking/dropping,that are used as congestion input in the traffic sources in order to balance their flow rate.However,in media-dominated networks,the key control goals have been considered to be stabilizing queuing delay and optimizing connection utilization.Most AQM algorithms are designed with a nominal operating point in mind,and the time-varying existence of network parameters.However,these algorithms often cause them to deviate from their robustness limits.To fix the time variation in the existence of network conditions induced by parameter variations and unresponsive connections,a self-tuning compensated proportionalintegral-derivative(PID)controller is planned in my work.Most congestion control algorithms,like TCP,rely on a reactive control system that detects congestion,and then marches carefully towards a desired operating point(e.g.by modifying the window size or adjusting a rate).We propose two algorithms,in which algorithm 1 CUSUM NLMS filter is used for the estimation of Traffic Road,while algorithm 2 CUSUM NLMS filter is used for the estimation of Link Capacity.In an effort to balance stability and convergence speed,the algorithms often take hundreds of RTTs to converge;an increasing problem as networks get faster,with less time to react.Active queue management schemes are used to reduce the number of dropped packets at the routers.Random early detection uses dropping probability is calculated based on the average queue size.Further it is modified according to the value of the count indicating that the number of unmarked packets that have arrived after a marked packet.The impact of random variable i.e.number of packets arrived after a marked packet over the dropping pattern is investigated.The proposed model achieves smooth dropping pattern which results in the improvement of quality of service parameters.A new model for dropping probability is proposed with different dropping function.The effect of new dropping probability results in the increase of the throughput and reduction of the expected end-to-end delay.An important finding is that the choice of modified dropping function significantly affected the performance measures of networks.A self-tuning AQM and network parameter estimation are part of the proposed scheme.The controller gains adaptation should compensate for the variation effects of traffic load,network latency,and bottleneck connection power,which are all time-varying network parameters.As the controller gains are simply and directly obtained from the dynamic model,the obtained self-tuning controller can reasonably adopt itself in different operating conditions,while protecting the easiness of the PI controllers.Intensely or edge switches signal the rate of blockage through the dynamic line in the executives(AQM)to the sources.The time-shifting nature of the organization elements and the mind boggling interaction of retuning the current AQM algorithm for various working focuses required the improvement of new AQM algorithm.Since the non-least stage attributes of the organization elements restrict the direct utilization of the relative proportional-integral-derivative(PID)regulator,we proposed a repaid PID regulator dependent on another control methodology tending to the stage slack and limitations brought about by the deferral.In view of the unsound interior elements brought about by the non-least stage qualities,a dynamic compensator is planned and a PID regulator is then permitted to meet the ideal exhibition targets by determining fitting elements for the following blunder.Since the regulator gains are acquired straight forwardly from the unique model,the planned regulator doesn't need to be tuned over the framework working wrap.Besides,recreation results utilizing ns2 show upgrades over past works particularly when the scope of variety of deferral and model boundaries are extraordinary.Effortlessness,low computational expense,self-tuning structure but extensive improvements in the execution are the selected elements of the proposed AQM for the edge or center switches.
Keywords/Search Tags:TCP networks, Congestion control, Queuing delay, Active queue management(AQM), Proportional-integral-derivative(PID), Random early detection, Modified dropping probability, End-to-end delay, Throughput, Loss-rate, Traffic load, Buffer size
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