What is a Network?
A network consists of two or more computers that are
linked in order to share resources (such as printers and CD-ROMs), exchange files,
or allow electronic communications. The computers on a network may be linked
through cables, telephone lines, radio waves, satellites, or infrared light
beams.
The three basic types of networks include:
Local Area Network
A Local Area Network (LAN) is a network that is
confined to a relatively small area. It is generally limited to a geographic
area such as a writing lab, school, or building. Rarely are LAN computers more
than a mile apart.
In a typical LAN configuration, one computer is
designated as the file server. It stores all of the software that controls the
network, as well as the software that can be shared by the computers attached
to the network. Computers connected to the file server are called workstations.
The workstations can be less powerful than the file server, and they may have
additional software on their hard drives. On most LANs, cables are used to
connect the network interface cards in each computer. See the Topology, Cabling, and Hardware sections of
this tutorial for more information on the configuration of a LAN.
Metropolitan Area Network
A Metropolitan Area Network (MAN) covers larger
geographic areas, such as cities or school districts. By interconnecting
smaller networks within a large geographic area, information is easily
disseminated throughout the network. Local libraries and government agencies
often use a MAN to connect to citizens and private industries.
One example of a MAN is the MIND Network located in
Pasco County, Florida. It connects all of Pasco's media centers to a
centralized mainframe at the district office by using dedicated phone lines,
coaxial cabling, and wireless communications providers.
Wide Area Network
Wide Area Networks (WANs) connect larger geographic
areas, such as Florida, the United States, or the world. Dedicated transoceanic
cabling or satellite uplinks may be used to connect this type of network.
Using a WAN, schools in Florida can communicate with
places like Tokyo in a matter of minutes, without paying enormous phone bills.
A WAN is complicated. It uses multiplexers to
connect local and metropolitan networks to global communications networks like
the Internet. To users, however, a WAN will not appear to be much different
than a LAN or a MAN.
