ABSTRACT
Telephonic communiques are viable when the customer is served by another person or the server. Also, it may happen while calling via telephone that when the first person calls the second person, the second person is busy on another call with a third person. In that case the first person receives a message that the second person is busy on the other call, the first person enters the virtual retrial orbit and as soon as the server or the second person becomes free the first person gets served. A retrial queueing system with one server subject to starting failures and with working vacations was studied by Yang et al. They applied a matrix geometric method for computing the orbit size after obtaining the system’s stability condition. The purpose was to calculate the optimal service rates during the vacation period and the normal period to minimize the expected cost per unit time.
