Simulation of a Retrial Queueing System with Two-Way Communication and an Unreliable Server in Different Scenarios

This paper seeks to explore a finite-source retrial queueing system featuring two-way communication and an unreliable server. Customers originate from a limited pool (primary customers) following an exponential distribution. Service for these customers begins if the service unit is available; if not, they are redirected to the orbit, attempting to connect with the server after a variable delay. A key characteristic of this system is that, upon the server becoming idle, it initiates an outgoing call (secondary customer) to both the orbit and the source, each governed by distinct parameters. Because the service unit is not reliable, the service of the customers may be interrupted which is also an exponential random variable. The unique aspect of this study lies in conducting a sensitivity analysis by applying various failure time distributions to assess their impact on key performance metrics across two distinct scenarios. The comparisons and findings are illustrated through graphical representations.