A computer network allows multiple computers to connect and share resources. It usually uses physical wires or cables to connect computers. There are different types of networks including local area networks (LANs), personal area networks (PANs), metropolitan area networks (MANs), wide area networks (WANs), wireless local area networks (WLANs), and campus area networks. LANs connect computers within a building while WANs connect LANs over longer distances.

1. COMPUTER
NETWORKS
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2. What is a ComputerNetwork?
A computer network is a system in which multiple computers
are connected to each other to share information and
resources.
Usually, the connections between computers in a network are
made using physical wires or cables
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3. • Characteristics
1. Share Resources from one computer to another
2. Create files and store them in one computer, access those
files from the other computer(s) connected over the network
3. Connect a printer, scanner or a fax machine to one computer
within the network and let other computers of the network use
the machines available over network.
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6. • Types of ComputerNetworks
There are different types of computernetworks. Some of the
common ones include.
1. Local Area Network LAN
2. Personal Area Network (PAN)
3. Metropolitan Area Network MAN
4. Wide Area Network WAN
5. Wireless Local Area Network WLAN
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7. LOCAL AREA NETWORK
(LAN)
A LAN is a network that is used for communicating among
computer devices, usually within an office building or home.
LAN’s enable the sharing of resources such as files or
hardware devices that may be needed by multiple users •
Is limited in size, typically spanning a few hundred meters,
and no more than a mile
Is fast, with speeds from 10 Mbps to 10 Gbps
Requires little wiring, typically a single cable connecting to
each device
 Has lower cost compared to MAN’s or WAN’s
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8. LAN’s can be either wired or wireless. Twisted pair, coax or
fibre optic cable can be used in wired LAN’s.
Every LAN uses a protocol – a set of rules that governs how
packets are configured and transmitted.
Nodes in a LAN are linked together with a certain topology.
These topologies include: – Bus – Ring – Star
LANs are capable of very high transmission rates (100s Mb/s
to G b/s).
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10. ADVANTAGES OF LAN
1. Files can be stored on a central computer (the file server)
allowing data to be shared throughout an organisation.
2. Files can be backed up more easily when they are all on a
central fileserver rather than when they are scattered
across a number of independent workstations.
3. Networks also allow security to be established, ensuring
that the network users may only have access to certain
files and applications.
4. Software and resources can be centrally managed.
5. Network versions of software often allow for their speedy
installation on workstations from the file server.
6. Expensive devices such as laser printers or scanners can
be shared.
7. Users can access their files from any workstation
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11. DISADVANTAGES OF LAN
1. Power - a good LAN is required to be on all the times.
2. Security - each computer and device become another point
of entry for undesirables.
3. Upkeep - when things go wrong or the software gets
updated.
4. Frustration if having a problem setting up.
5. A lot of times a network shares one Internet connection - if all
computers running at once, can reduce speed for each.
6. Area covered is limited.
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12. PERSONAL AREA NETWORK
 A PAN is a network that is used for communicating among
computers and computer devices (including telephones) in
close proximity of around a few meters within a room
 It can be used for communicating between the devices
themselves, or for connecting to a larger network such as the
internet.
 PAN’s can be wired or wireless
A personal area network (PAN) is a computer network used
for communication among computer devices, including
telephones and personal digital assistants, in proximity to an
individual's body.
The devices may or may not belong to the person in
question. The reach of a PAN is typically a few meters.
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14. METROPOLITAN AREA
NETWORK (MAN)
A metropolitan area network (MAN) is a large computer
network that usually spans a city or a large campus.
A MAN is optimized for a larger geographical area than a
LAN, ranging from several blocks of buildings to entire cities.
 A MAN might be owned and operated by a single
organization, but it usually will be used by many individuals
and organizations.
A MAN often acts as a high speed network to allow sharing of
regional resources.
A MAN typically covers an area of between 5 and 50 km
diameter.
Examples of MAN: Telephone company network that
provides a high speed DSL to customers and cable TV
network.
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16. ADVANTAGES OF MAN
MAN can cover a wider area than a LAN. MAN networks are
usually operated at airports, or a combination of several pieces
at a local school.
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17. DISADVANTAGES OF MANs
The key disadvantage of MANs is the cost of the cutting-edge
technology employed. Also, this equipment generally has to be
installed for the first time, as the copper traditionally used for
the phone network is generally considered to be too slow to be
annexed for this purpose.
The cost is what inhibits the geographical reach of MANs,
which is also another drawback.
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18. WIDE AREA NETWORK
WAN covers a large geographic area such as country,
continent or even whole of the world.
A WAN is two or more LANs connected together. The LANs
can be many miles apart.
To cover great distances, WANs may transmit data over
leased high-speed phone lines or wireless links such as
satellites.
Multiple LANs can be connected together using devices such
as bridges, routers, or gateways, which enable them to share
data.
 The world's most popular WAN is the Internet.
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20. CAMPUS AREA NETWORK
•A campus network is a proprietary local area network (LAN) or
set of interconnected LANs serving a corporation, government
agency, university, or similar organization.
•The end users in a campus network may be dispersed more
widely (in a geographical sense) than in a single LAN, but they
are usually not as scattered as they would be in a wide area
network (WAN).
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21. College and university campus networks interconnect
administrative buildings, residence halls, academic halls,
libraries, student centers, athletic facilities, and other buildings
associated with the institution in a specific town or
neighborhood. Corporate campus networks interconnect
buildings that house key departments and staff members. The
corporate campus network forms the user-facing aspect of the
larger corporate network within a limited geographic area.
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