This presentation is about computer networks and topologies. (Basic)

1. COMPUTER NETWORKS
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2. Introduction
Primarily computer networking means connecting
different devices.
As the technology improved, it became possible to link
together several computers in such a way that users on
one system could use the facilities of other systems in
the network.
The area covered by a network can range from a
university campus to many continents.
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3. Computer network
A computer network can be defined as two or more computers
connected together in such a way that they can share resources.
It means when computers or their associated devices are
connected through a medium is known as a computer network.
The medium through which computer systems are connected
may be wired or wireless.
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4. Advantages of computer network
 Easy communication: Using a network, people can communicate efficiently and easily via email, instant
messaging, chat rooms, telephone, video telephone calls, and video conferencing.
 Resource sharing: using network-connected peripheral devices like printers, scanners and copiers, or
sharing software between multiple users, saves money.
Well security system: Sensitive files and programs on a network can be password protected Then those
files can only be accessed by the authorized users.
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5. Disadvantages of computer network
 Expensive to build and manage: Building a network is a serious business, especially for large scale
organizations. Cables and other hardware are costly to buy and replace. Also Managing a large network is
complicated, requires training and a network manager usually needs to be employed.
 Security threats: There are hackers who are trying to steal valuable data of large companies for their
own benefit. So it is necessary to take utmost care to facilitate the required security measures. Also if any
computer system in a network gets affected by a computer virus, there is a possible threat of other
systems getting affected
Dependency on the file server: In case the File Server of a computer network breaks down, the whole
network is unable to operate
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6. Classification of networks
We can classify networks in different ways-
Transmission media: Wired (Twisted-Pair cables, coaxial cables, fiber-optic cables) and Wireless
(radio wave, microwave, infrared signal, sound)
Network size
Management method: Peer-to-peer and Client/Server.
Topology: Point to Point, Bus, Star, Ring, Mesh, Hybrid
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7. Computer networks based on size
1. Personal Area Network (PAN)
2. Local Area Network (LAN)
3. Metropolitan Area Network (MAN)
4. Wide Area Network (WAN)
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8. Computer networks based on size
Difference between different computer networks
SL PAN LAN MAN WAN
1 Smallest Network Single
administrative system
Network within single
large city.
Large network of information
that is not tied to a single
location
2 Personal to a user. Covers an organization’s
offices, schools, college/
universities
Spans a
metropolitan area or
campus.
Used to connect cities, states,
or even countries
3 Connectivity range up to
10 meters.
Number of systems may vary
from as least as two to as
much as 16 million.
Larger the city, the
bigger the MAN, the
smaller a metro city,
smaller the MAN.
Covers a broad area
which may span across
provinces and even a whole
country.
Example Bluetooth Office network Cable TV network Internet
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9. Intranet vs Extranet
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Intranet Extranet
Intranet is owned by a single organization Extranet is owned by either a single or a many
organization
type of Internet that is used privately tool for sharing information between the
internal members and external members
Intranet is highly secure and has a small
number of visitors
Extranet is used to check status, access data,
send mail, place order etc.

10. Some Networking terms
IP address: An Internet Protocol address (IP address) is a unique string of numbers
separated by full stops that identifies each computer using the Internet Protocol to
communicate over a network.
Ethernet: A system for connecting a number of computer systems to form a local
area network, with protocols to control the passing of information and to avoid
simultaneous transmission by two or more systems.
Fiber-optic: Fiber-optic communication is a method of transmitting information from
one place to another by sending pulses of light through an optical fiber. It is normally
used in WAN communication.
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