Performance analysis of preemptive priority retrial queue with immediate Bernoulli feedback under working vacations and vacation interruption

The present investigation deals with performance analysis of single server preemptive priority retrial queue with immediate Bernoulli feedback. There are two types of customers are considered, which are priority customers and ordinary customers. The priority customers do not form any queue and have an exclusive preemptive priority to receive their services over ordinary customers. After completion of regular service for ordinary customer, the customer is allowed to make an immediate feedback with probability r. When the orbit becomes empty at service completion instant for a priority customer or ordinary customer; the server goes for multiple working vacations. By using the supplementary variable technique, we obtained the steady state probability generating functions for the system/orbit. Some important system performance measures, the mean busy period and the mean busy cycle are discussed. Finally, some numerical examples are presented.