Introduction to the queueing theory, Kendall's notation, recursion for waiting times, stability, Little's law, elementary queueing theory including birth–death process and M/M/1, M/M/m as well as M/M/m/m queues, analysis methods and stationary distributions for M/G/1, G/M/1, G/G/1 queues, bounds, heavy traffic approximation, diffusion approximation.