Abstract
This paper deals with the steady-state behavior of an MX/G/1 retrial queue with an additional second phase of optional service and service interruption where breakdowns occur randomly at any instant while the server is serving the customers. Further, the concept of delay time is also introduced in the model. This model generalizes both the classical MX/G/1 retrial queue with service interruption as well as the MX/G/1 queue with second optional service and service interruption. We carry out an extensive analysis of this model.