This document provides an overview of different types of computer networks: 1) A simple network connects two devices like computers directly via a wire or cable for communication. 2) A local area network (LAN) connects a group of computers in a home, school, or office building. It features a switch to control traffic to a local server and a firewall to protect the LAN from internet threats. 3) Larger wired networks connect LANs to the internet via phone or cable lines from an Internet Service Provider, which then connects to the global fiber optic internet backbone.