In general, queueing systems may be characterized by complex input process, service time distribution,
number of servers (or channels), buffer size (or waiting room) and queue disciplines.
In practice, such queueing processes and disciplines are often not amenable to analysis. Nevertheless,
insight can be often gained using simpler queueing models. Modelling simplification is
often made when the aim is to analyze a complex queueing system or network, such as the Internet,
where packets on their ways to their destinations arrive at a router where they are stored
and then forwarded according to addresses in their headers. One of the most fundamental elements
in this process is the single-server queue. One of the aims of telecommunications research
is to explain traffic and management processes and their effect on queueing performance. In
this section, we briefly cover basic queueing theory concepts. We shall bypass mathematically
rigorous proofs and rely instead on simpler intuitive explanations.