Admission control policy of a two heterogeneous server finite capacity retrial queueing system with maintenance activity

This paper investigates the concept of admission control policy of a two heterogeneous server finite capacity retrial queueing system with maintenance activity. An arriving customer can receive service immediately if any one of the servers is found to be available. If the servers are busy, the customer may await its turn in the orbit. After a random amount of time, the orbital customers may check for the availability of servers and retry requesting service on a first come first serve basis. The concept of admission control policy is adopted to ensure a smooth utilization of the orbit space. In this policy, when the system size reaches the maximum capacity, the arriving customers are restricted from joining the orbit until the system size reduces to a threshold level. When a server becomes idle with no customer waiting to be served, it is subject to maintenance. The Chapman-Kolmogorov equations of the governing model are derived to study their queueing characteristics. Recursive technique is used to analyse the system size distributions in steady state. This enables us to acquire the various performance measures of the model under study. The effects induced by the system parameters on the performance metrics are numerically and graphically analysed.