A computer network is a set of two or more computers connected together in order to share information and resources like printer and scanner etc. A computer network can be classified into three types according to their size: LAN, MAN and WAN. LAN stands for Local Area Network. It covers a small area. LANs are used to connect computers in a single building or group of buildings. MAN is short for Metropolitan Area Network. It covers a metropolitan area. They are good for businesses and organizations that have multiple locations around a city. WAN is short for Wide Area Network. It refers to a network that covers a large area. It connects computers in different cities, countries and continents.
A network is classified into two types: peer-to-peer and client server. In peer to peer network, computers act as both workstations and servers. Each machine can have resources that are shared with any other machine. In client server network, the server controls the network access of the other computers which are referred to as the 'client' computers.