ABSTRACT
This chapter aims to avoid discussion of the mathematical means of arriving at solutions to particular cases and to give a general appreciation of some of the principal features arising from the theory. The original work concerning the theory of queues was undertaken around 1908 for the Copenhagen Telephone Company Limited by A. K. Erlang when investigating the problem of customer queueing for telephone calls. The average time to pass through each stage is usually taken to be the same, although solutions are available based on other assumptions. Solutions to queueing situations when a steady state has been reached are generally easier to obtain mathematically than otherwise, although even then the mathematics can become very complicated. Sometimes a server will postpone service until a certain number of customers are available and then process in bulk. Other interesting cases arise when there are a limited number of customers to serve, as, for example, when one operator services a number of machines.
