Self-oscillation modes in control systems of data transmission networks negatively affect the characteristics of these networks. To investigate the self-oscillation mode for systems with a control module, the analytical model of the active queue management module was developed. The problem of verification of the obtained theoretical results arises in the study. Previously, a software system was developed for software emulation of the router. However, its use has caused some difficulties. Alternatively, the simulation model of network with active queue management module was developed. The paper describes a software package for verifying theoretical calculations based on the NS-2 simulation system. For illustration, a numerical example is given.

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In this paper we consider the dynamics of large-scale queueing systems with an infinite number of servers. We assume that there is a Poisson input flow of requests with intensity . We suppose that each incoming request selects two any servers randomly and at the next step of an algorithm is sending this request to the server with the shorter queue instantly. A share ( ) of the servers that have the queues lengths with not less than can be described using a system of ordinary differential equations of infinite order. We investigate this system of ordinary differential equations of infinite order with a small real parameter. A small real parameter allows us to describe the processes of rapid changes in large-scale queueing systems. We use the simulation methods for this large-scale queueing systems analysis. The numerical simulation show that the solution of the singularly perturbed systems of differential equations have an area of rapid change of the solutions, which is usually located in the initial point of the problem. This area of rapid function change is called the area of the mathematical boundary layer. The thickness of the boundary layer depends on the value of a small parameter, and when the small parameter decreases, the thickness of the boundary layer decreases. The paper presents the numerical examples of the existence of steady state conditions for evolutions ( ) and quasi-periodic conditions with boundary layers for evolutions ( ).Key words and phrases: countable Markov chains, large-scale queueing systems, singular perturbed systems of differential equations, differential equations of infinite order, small parameter