Research will investigate scheduling control problems of queueing networks that arise in production systems, and computer and communication networks. Despite much attention, a systematic approach to the scheduling control of general structured networks is not available. The investigator should solve the scheduling control problems by using a simple and highly aggregated model, namely, a fluid model. The viewpoint taken is that the simple model often provides the insight to the complicated problem, the solution to practical problems, and the basis for studying more complicated models. Recent work has shown that the fluid model approach can reduce a scheduling control problem to solving a set of linear programming problems, and in some cases the solution when properly interpreted can be optimal for the queueing system. Research will be performed in four steps: (1) modeling queueing system by fluid model, (2) solving the scheduling control problem of the fluid model, (3) interpreting the solution into the control rule for the original queueing system, and (4) testing the solution by simulation.