Numerical analysis of a retrial system with unreliable servers based on Laplace transform description

In this paper, we consider a retrial queuing system with unreliable servers and analyse the distribution of the stationary generalized service time which includes also the unavailable periods (setup times) occurring during service of the customer. We consider three service interruptions disciplines: preemptive resume (PRS), preemptive repeat different (PRD) and preemptive repeat identical (PRI); and provide the stationary distribution of the generalized service time and the remaining generalized service time with these disciplines in Laplace transform (LT). The main focus of the paper is on the numerical analysis based on LST domain descriptions, which we evaluate for various numerical examples.