Networks . . . such a simple concept . . . . moving data from point A to point B.
But what a powerful concept. By networking computers together, people from remote locations can work together as a team . . . share projects, send messages, access databases, etc.
Remember the old days, where a network consisted of IBM Mainframes surrounded by a bunch of dumb terminals? Thankfully, that era is gone. Even when they replaced the dumb terminal with smart workstations – it was very limiting to have to send everything through the same, central place. In today’s world, we use shared Client-Server and peer-to-peer topologies. Although there are many protocols used to connect the nodes together, and hence many network types – there are three defined sizes of Networks . . . LAN, MAN, and WAN . . .
LAN (Local Area Network) – a computer network confined to a relatively small area, such as a single building or a group of adjacent buildings. A LAN can cover an entire campus, so long as the buildings are directly connected. The nodes (computers, printers, servers, etc.) are connected via bridges and routers. Devices can be connected by twisted-pair wire, coaxial cables, or fiber optic cables.
MAN (Metropolitan Area Network) – a data network designed for a town or city. In terms of geographic breadth, MANs are larger than local-area networks (LANs), but smaller than wide-area networks (WANs). Some MAN networks do without connecting media altogether, communicating instead via radio waves, using dish antenna’s on rooftops.
WAN (Wide Area Network) – a computer network that spans a relatively large geographical area. Typically, a WAN consists of two or more local-area networks (LANs). Computers connected to a wide-area network are often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites. The largest WAN in existence is the Internet.
The definitions can blur a bit. Basically, a LAN becomes a MAN if there are connections between separate LAN’s across a town or city – typically via a LEC (Local Exchange Carrier), such as Bell South or Verizon. A MAN becomes a WAN if there are connections between separate LAN’s across the country – typically via an IXC (InterExchange Carrier) such as AT&T, Sprint, or MCI.
For example, if a company had two sister sites in Philadelphia and New York . . . each with their own LAN, and they decided to connect them together by purchasing a T1 (a 1.544 Mbps data connection) from MCI – then each city still has it’s own LAN, but the two LAN’s connected together is WAN.