Queueing theory and modeling provide us with “closed-form” analytical solutions to problems involving, reasonably enough, queues. Indeed, this type of performance-focused modeling is central to properly planning and sizing infrastructure and facilities of many types, from a new hospital building with interconnected services to servers, bridges, and routers on a distributed communications network, checkout registers at a retailer, toll booths (and lanes) on an interstate, conveyor belts at an airport, or teller and drive-through windows at a bank. Complex models can be joined to form queueing networks.
No, it does not in either case. Simulation provides a platform for the development of models. Simulation can be contrasted with “closed-form” mathematical solutions to problems, which give an exact answer — think queueing models. Because closed-form models can be very unwieldy and complex to develop and explain to non-mathematicians, we increasingly rely on software that allows us to model ideas via a graphical user interface (GUI) and then run and test our model using the underlying simulation engine.