There
are so many different types of computer networks in existence; it can be hard
to understand the differences between them, particularly the ones with very
similar-sounding names. This lesson explains the structures and functions of
some of the most popular computer networks.
Types of Networks
There are several
different types of computer networks. Computer networks can be characterized by
their size as well as their purpose.
The size of a network
can be expressed by the geographic area they occupy and the number of computers
that are part of the network. Networks can cover anything from a handful of
devices within a single room to millions of devices spread across the entire globe.
Some of the different
networks based on size are:
- Personal area
network, or PAN
- Local area network,
or LAN
- Metropolitan area
network, or MAN
- Wide area network,
or WAN
In terms of purpose,
many networks can be considered general purpose, which means they are used for
everything from sending files to a printer to accessing the Internet. Some
types of networks, however, serve a very particular purpose. Some of the
different networks based on their main purpose are:
- Storage area
network, or SAN
- Enterprise private
network, or EPN
- Virtual private
network, or VPN
Let's look at each of
these in a bit more detail.
Personal Area Network
A personal area
network, or PAN, is a computer network organized around an individual
person within a single building. This could be inside a small office or
residence. A typical PAN would include one or more computers, telephones,
peripheral devices, video game consoles and other personal entertainment
devices.
If multiple individuals
use the same network within a residence, the network is sometimes referred to
as a home area network, or HAN. In a very typical setup, a residence will have
a single wired Internet connection connected to a modem. This modem then
provides both wired and wireless connections for multiple devices. The network
is typically managed from a single computer but can be accessed from any
device.
This type of network
provides great flexibility. For example, it allows you to:
- Send a document to
the printer in the office upstairs while you are sitting on the couch with
your laptop.
- Upload a photo from
your cell phone to your desktop computer.
- Watch movies from
an online streaming service to your TV.
If this sounds familiar
to you, you likely have a PAN in your house without having called it by its
name.
Local Area Network
A local area
network, or LAN, consists of a computer network at a single site,
typically an individual office building. A LAN is very useful for sharing
resources, such as data storage and printers. LANs can be built with relatively
inexpensive hardware, such as hubs, network adapters and Ethernet cables.
The smallest LAN may
only use two computers, while larger LANs can accommodate thousands of
computers. A LAN typically relies mostly on wired connections for increased
speed and security, but wireless connections can also be part of a LAN. High
speed and relatively low cost are the defining characteristics of LANs.
LANs are typically used
for single sites where people need to share resources among themselves but not
with the rest of the outside world. Think of an office building where everybody
should be able to access files on a central server or be able to print a
document to one or more central printers. Those tasks should be easy for
everybody working in the same office, but you would not want somebody just
walking outside to be able to send a document to the printer from their cell
phone! If a local area network, or LAN, is entirely wireless, it is referred to
as a wireless local area network, or WLAN.
Metropolitan Area Network
A metropolitan area
network, or MAN, consists of a computer network across an entire city,
college campus or small region. A MAN is larger than a LAN, which is typically
limited to a single building or site. Depending on the configuration, this type
of network can cover an area from several miles to tens of miles. A MAN is
often used to connect several LANs together to form a bigger network. When this
type of network is specifically designed for a college campus, it is sometimes
referred to as a campus area network, or CAN.
Wide Area Network
A wide area network,
or WAN, occupies a very large area, such as an entire country or the
entire world. A WAN can contain multiple smaller networks, such as LANs or
MANs. The Internet is the best-known example of a public WAN.
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