In principle there is an infinite number of possibilities for service disciplines, since it is an arbitrary function to select an element from sets. Service dis

In principle there is an infinite number of possibilities for service disciplines, since it is an arbitrary function to select an element from sets. Service disciplines can also include randomness. I only know the basics of the mathematics of queue theory, but my introduction to it gave me the impression that almost anything but the most basic of disciplines didn't have closed form solutions to most questions. Like many models, you can introduce some things as approximations to get close enough answers. I personally prefer simulation, but that has its own problems.