摘要
A novel closed-loop feedback TCP/AQM(Transfer Control Protocol/Active Queue Management) model is proposed in this paper using a discrete-time Markov chain,and a way to calculate the equilibrium distribution of this model is given.In the model,system time is divided into time slots,the bottleneck router queue model and TCP window size model in each slot are analyzed.Finally,by combining adjacent slots,an integrated TCP/AQM analytical model is developed.By this model,the average values of packets dropping ratio and queue length in the router and TCP sending rate can be estimated,hence,this model could be a useful tool for the analysis of AQMs and support the development of new AQM schemes theoretically.The proposed TCP/AQM model is extended to a TCP-UDP(Control User Datagram Protocol)/AQM model,to analyze the TCP/AQM system performance when UDP flows exist.By implementing this model on Matlab,we compare its solutions to NS2 simulated solutions,then the validity of the model to analyze the closed-loop feedback TCP/RED(Random Early Detection) system is verified.
A novel closed-loop feedback TCP/AQM （Transfer Control Protocol/Active Queue Management） model is proposed in this paper using a discrete-time Markov chain, and a way to calculate the equilibrium distribution of this model is given. In the model, system time is divided into time slots, the bottleneck router queue model and TCP window size model in each slot are analyzed. Finally, by combining adjacent slots, an integrated TCP/AQM analytical model is developed. By this model, the average values of packets dropping ratio and queue length in the router and TCP sending rate can be estimated, hence, this model could be a useful tool for the analysis of AQMs and support the development of new AQM schemes theoretically. The proposed TCP/AQM model is extended to a TCP- UDP （Control User Datagram Protocol）/AQM model, to analyze the TCP/AQM system performance when UDP flows exist. By implementing this model on Matlab, we compare its solutions to NS2 simulated solutions, then the validity of the model to analyze the closed-loop feedback TCP/RED （Random Early Detection） system is verified.
基金
Supported by the National Natural Science Foundation of China (No.60572093)
Specialized Research Fund for the Doctoral Program of Higher Education (20050004016) of China
