Reliability analysis of finite-source retrial queues with outgoing calls using simulation

The aim of this paper is to create a simulation program in order to examine systems of two-way communication by the help of retrial queuing systems with finite source. Primary customers arrive from a finite source to the server according to exponential distribution. If an incoming customer discovers the server in an idle state then its service begins right away. Otherwise, if the server is busy or in failed state arriving primary customers move into the orbit and after some random time they try to reach the server. Whenever the server becomes idle it produces an outgoing call after an exponentially distributed time from the infinite source. If no primary customer arrives either from the finite source or from the orbit and the server functions until its arrival then it enters to the system. Otherwise, the outside call is cancelled. Several scenarios are distinguished when the server is in failed state and in this work we concentrate on comparing various distributions of service time of primary customers and failure probability of the server. The novelty of the investigation is to analyze such system with non-reliable server. Various figures illustrate comparison of using different scenarios showing the mean waiting time of primary customers and the utilization of the server obtained by simulation.