Networks occur when computer systems are connected together.
There are local area networks that connect computer systems that are close together, such as in a room or on a floor of a building. For example, the computer lab in your school may be a local area network because it connects all the personal computers in the lab. There are also enterprise-wide networks that connect the computer systems in a company or organization together. For example, the computer systems at a university, government agency, or business may be connected together. Then there are wide area networks that connect computer systems together across large distances.