Abstract
We examine the service mechanism of two queueing models with two units
in tandem. In the first model, customers who complete service in Unit 1
must wait in an intermediate buffer until the ongoing service in Unit II
ends. In the second model, jobs can be pre-positioned in an intermediate
buffer to await service in Unit II. Under the assumption of phase-type service times, the steady-state regime of the service system is studied in detail.The models are inspired by the gas pump model of A.B. Clarke and
by phenomena observed in cafeteria lines and certain manufacturing systems. However, their primary interest may lie in the methodology of their
exceptionally tractable analysis. We derive formulas for the throughput
and other quantities by using the familiar