What should we expect queueing models to do for us, and what should we expect them not to be able to do?

Question

What are queueing models used for in networking, why, how accurate are they etc. What should we be able to expect queueing models to do for us, and what should we expect them not to be able to do?

Answer 1

Another homework question...?

A queuing model is a theoretical abstraction that has no practical bearing in the real network world. Input traffic is never as nicely behaved as whatever distribution you care to assume. The practical queuing mechanisms that are implementable in a cost-effective mechanism inevitably do not match what theory assumes. As a result, the theoretical results are not at what is seen in practice.

As a result, queuing theory, at best, gives us some upper bound on what's achievable and gives us some intuitive understanding of some of the fundamental mistakes that be made in trying to achieve a particular queuing behavior.

Note that submitting this answer is likely to get you a 'D', but it's the truth of the matter.