Queueing Theory in Practice

Queueing theory evolved originally out of an investigation of problems dealing with the design of telephone systems. Now, some 70 years later, we are witnessing a tremendous accumulation of theoretical results for “idealized” systems that apparently have not been as effective in dealing with other types of real-life problems. Queueing theory differs from other mathematical techniques of Operations Research in that it does not deal with optimization models. Rather, it utilizes mathematical analysis to determine the system's measures of effectiveness such as the expected waiting time per customer and the facility's percentage of idle time. These measures are then used as data in the context of an optimization (cost) model for determining the system's capacity. The obstacles in applying queueing theory to practical problems occur both in modeling the system mathematically and in determining its optimum design parameters. This paper identifies the areas of application in terms of their amenability to analysis by queueing theory, and provides suggestions that can enhance the applicability of queueing models in real life.