An M/G/1 retrial queueing system with two phases of service subject to the server breakdown and repair

This paper deals with the steady state behaviour of an M/G/1 retrial queue with an additional second phase of optional service subject to breakdowns occurring randomly at any instant while serving the customers. This model generalizes both the classical MIGI I retrial queue Subject to random breakdown as well as M/G/1 queue with second optional service and server breakdowns. We carry out an extensive analysis of this model. (C) 2008 Elsevier B.V. All rights reserved.