Performance Analysis of an Unreliable M/G/1 Retrial Queue with Coupled Switching

We investigate the stationary characteristics of an M/G/1 retrial queue where the server, subject to active failures, primarily attends incoming calls and directs outgoing calls only when idle. On finding the server unavailable (busy or failed), inbound calls join the orbit and reattempt for service at exponentiallydistributed time intervals. The system stability condition and probability generating functions of the number of calls in orbit and system are derived and evaluated numerically in the context of mean system size, server availability, failure frequency, and orbit waiting time.