This document defines and describes different types of computer networks. It discusses local area networks (LANs) that connect devices within a building using cables or wirelessly, metropolitan area networks (MANs) that span a larger area like a city using technologies like DSL, and wide area networks (WANs) that connect LANs over long distances using technologies like fiber optics or satellites. It also covers personal area networks (PANs) used to connect devices in close proximity, within a few meters of an individual.