Dynamics and the periodic solutions of the delayed non-smooth Internet TCP-RED congestion control system via HB–AFT

Abstract

This paper has attended to obtain the approximate analytical expressions of periodic solutions in the delayed non-smooth Internet TCP-RED congestion control system employing the semi-analytical method named as the harmonic balance method with alternating frequency/time (HB-AFT) domain technique. For the first time, the methodology presented herein provides the accurate approximate analytical expressions of periodic solutions, including the non-impacting periodic solutions and impacting periodic solutions, in the non-smooth dynamical system with time-delays. They agree very well with the results of numerical simulations by MATLAB. It implies that the proposed method in this paper is accurate and effective. Furthermore, rich dynamics of this delayed non-smooth system is discovered in the present paper. Three kinds of bi-stability, i.e. coexistence of asymptotically stable equilibrium and equilibrium, equilibrium and periodic solution, periodic solution and periodic solution, have been found in the system with the variation of the delay. And the grazing solution, the impacting solution traversing both the lower threshold Tmin and the larger threshold Tmax, and a route to chaos, i.e., intermittent to chaos, have been also obtained by varying the delay employing numerical method.