Comparison of Two Operation Modes of Finite-Source Retrial Queueing Systems with Collisions and a Non-Reliable Server by Using Simulation

Abstract

In this paper a finite-source retrial queuing system with collision of the customers is investigated by means of computer simulation. The server is not reliable; it is subjected to breakdowns, and the repairs depend on whether the state of the server is idle. The random variables used in the model are jointly independent and are exponential and gamma distributed. Two operation modes are considered in the case of busy breakdown. The novelty of the investigation is a comparison of the performance measures of these modes, and estimations obtained by the simulation are graphically illustrated showing the influence of the difference of the working modes on the performance measures such as mean and variance of the response time, mean and variance of the number of customers in the system, mean and variance of the sojourn time in the orbit, mean and variance of time time a customer spent in service.