This document discusses computer networks and their applications. It defines a computer network as a system connecting computers and devices. Communication involves transferring information from a sender to a receiver. Networks can use analog or digital signals, with computers using digital.
There are three main types of networks: local area networks (LANs) covering a small physical area; metropolitan area networks (MANs) connecting devices within a city; and wide area networks (WANs) spanning large distances like countries. Network architectures include client-server models and peer-to-peer networks. Topologies encompass bus, ring, star, tree and mesh configurations. Computer networks enable file sharing, printing, collaboration, remote access, data protection and centralized administration.