This document discusses different types of computer networks. It defines a computer network as a group of connected computers that share resources and communicate. There are four main types of networks: local area networks (LANs) which connect computers in a small area like a building; personal area networks (PANs) which connect devices within 10 meters of a person; metropolitan area networks (MANs) which connect computers in a city; and wide area networks (WANs) which connect computers over a large geographic area. LANs use technologies like Ethernet cables to connect computers in an office at high speeds and provide security. PANs connect personal devices within 30 feet, like phones and laptops.