Based upon the geographical distribution of computers connected to a 
  network there are mainly three types of network.
    Local Area Network (LAN)
    Metropolitan Area Network (MAN)
    Wide Area Network (WAN)
              Local Area Network (LAN)
 A Local Area Network (LAN) is a group of interconnected computers, printers and other 
 devices that are situated within a radius of 1 km and normally they belong to a single 
 organisation.
 The following are the salient features of a LAN:-
 1) LAN is limited by distance.
 2) The rate at which data is transferred between two computers in the network is very high.
 3) Cables are used as primary medium of data transmission.
 4) The users share hardware as well as software resources through LAN.
            Metropolitan Area Network (MAN)
 A Metropolitan Area Network (MAN) is a data network that interconnects the users with 
 computer resources, usually with a spread of a town or a city, using fiber-optical cable or other 
 digital media.
 The following are the features of MANs:-
 1) The connections between computers are through the local telephone network.
 2) Usually a dedicated leased line is provided by the telephone company to each user, so that, 
 no one else can make unauthorised use of the network.
 3) The network size remains between LAN and MAN.
 4) Unlike LAN, a MAN is not generally owned by a single organisation. It may be owned by 
 either a consortium of users or a single network service provider who sells the services to the 
 users.
              Wide Area Network (WAN)
  Wide Area Network (WAN) is the largest computer network to which the computers, 
  located across all over the world, are connected. The computers connected to WAN are 
  often connected through public network system such as telephone system. The most 
  popular and largest WAN is the internet.
  There are two types of WAN:-
  1) Private WANs and
  2) Public WANs.