TWO-CLASS M/PH,G/1 QUEUE WITH IMPATIENCE OF HIGH-PRIORITY CUSTOMERS

We consider the M/PH,G/1 queue with two classes of customers in which class-1 customers have deterministic impatience time and have preemptive priority over class-2 customers who are assumed to be infinitely patient. The service times of class-1 and class-2 customers have a phase-type distribution and a general distribution, respectively. We obtain performance measures of class-2 customers such as the queue length distribution,the waiting time distribution and the sojourn time distribution,by analyzing the busy period of class-1 customers. We also compute the moments of the queue length and the waiting and sojourn times.