TCP/Active Queue Management Model and Simulation for Bottleneck Networks
Caixia Chi · 2009
A novel delayed closed-loop feedback TCP/AQM analytical model was proposed by using discrete-time Markov chain, and the calculation method for equilibrium distribution was given. The system time was divided to time slots with the cycle of RTT (Round Trip Time) with different lengths. In each slot, the bottleneck router queue model and TCP window size model were analyzed. By combining adjacent slots, an integrated TCP/AQM analytical model was developed. The expectation values of packets dropping ratio and queue length in the bottleneck router and TCP senders’ window size could be estimated, hence, it is a useful tool for the analysis of AQMs and supporting the development of new AQM schemes theoretically. By implementing this model on Matlab, its solutions were compared to NS2 simulated solutions, and the validity of the model to analyze the closed-loop feedback TCP/RED system was verified.