Reliability Analysis of Finite-Source Retrial Queueing Systems With Two-Way Communications to the Orbit and Blocking Using Simulation

A two-way communication retrial queueing system is considered with a single server which from time to time is subject to random breakdowns. The investigated model is an $M/M/1//N$ type system where the number of sources is finite. Once the service unit becomes idle it can call in customers residing in the orbit (outgoing call or secondary customers). Distribution of the service time of primary and secondary customers is exponential with rates μ1 and μ2, respectively. In the model construction, all random variables are assumed to be totally independent of each other. When the server is failed the operation of the system is blocked resulting that throughout this period customers can not enter the system. The novelty of this analysis is to study the effect of blocking in such a system on the main performance measures using a different distribution of failure time. Results are illustrated graphically with the help of a simulation program developed by the authors.