Basics of computer network

1. COMPUTER
NETWORKS

2. What is a network?
 The term network is familiar to us, for example railway
network, airways network, television network, sales network
etc.
 A railway network connects numerous location with one
another and fulfills a common requirement of “Travelling”.

3. Networking
 The concept of networking was introduced by the IT industry. Here
computers are connected to each other, in order to exchange information
with one another.
 Networking refers to creating networks. A network is a group of devices
connected with one another.
 A computer network is a collection of computers and peripheral devices
such as printers, connected by a communication links.
 These links allow the network components to work together. These
components may be located at a remote location or in the same building.

4. Creating a computer network
 A network can be of any size. For
example, a small network can be created
by connecting as few as two computers
for sharing files.
 A network can also connect millions of
computers to exchange information all
over the world. The world’s largest
network is the Internet.
 Your computer is a workstation on the
network.

5. Components of a Network
1. Workstation:
Stand-alone computers or computers which
are connected to the network are referred to as
workstation.
2. Peripherals:
These are other devices like printers, plotters
and modems that are connected to the
network. These are expensive resources that
can be shared by all the computers in a
network.

6. Components of a Network
3. Servers:
A network is a multi-user system because more than
one person can send request to a machine at a time.
A server is powerful computer that handles requests
and distributes the network resources such as files
and printers.
4. Transmission Media:
A network cannot be formed without media.
Communication channel is the medium through
which data is exchanged between the computer in a
network. Transmission media can be classified as
cables or wireless.

7. Types of Cable
Twisted Pair Cable Coaxial Cable Fiber-optic Cable

8. Types of Network
LAN
WAN
MAN

9. Local Area Network
 A Local Area Network (LAN) is the
most common type of network.
 A local area network connects
computers and devices located close to
one another, such as in one building.
 Usually, LAN has no more than 100
computers. For example: school
computer lab and home networks.

10. Metropolitan Area Network
 A Metropolitan Area Network
(LAN) is collection of local area
networks.
 Metropolitan Area Network
connects computers located in
the same geographical area such
as a city or a town.

11. Wide Area Network
 A Wide Area Network (WAN)
connects local and metropolitan
area networks together.
 The networks that make up a
wide area network may be
located throughout a country or
even around the world.

12. Wireless LANS
 More and more networks are operating
nowadays without cables, they are called
wireless mode.
 Wireless LANs use high frequency radio
signals, infrared light beams or lasers to
communicate between the workstations and
the file server.
 Wireless networks are great for allowing laptop
computers or remote computers to connect to
LAN. It is also beneficial in older buildings
where it may be difficult or impossible to install
cables.

13. Advantages of Networks
 Ease of Access
 The network stores most of the information in a central computer.
Storing information in a central computer makes it easy for people to
work with and manage the files.
 Work from Home
 The network has dedicated computers that allow people to connect to
the company’s network using a modem. Once users are connected to
the network, they can work with any data stored on the network.
Network makes it easy for people to access office information from
their homes.

14.  Sharing information
 You can use network to share information with other people. Information can
be of any form such as documents or databases.
 Sharing Resources
 Computers connected to a network can share equipment and devices which
are called resources. The ability to share resources reduces the cost of buying
computer hardware.
 Productivity
 Using computer connected to a network people can exchange information
with each other and hence they can work more efficiently thereby increasing
the productivity.

15.  Cost
 Network allows computers to share many types of resources such as printers and
hard drives thereby reducing the cost.
 Administration
 Networks make it easier to monitor and control your company’s computers.
 Security
 Networks has built-in security programs which can monitor and report any
abnormal activity on a network to administrator.
 Programs
 With network all the computers can use the same program which is installed on
only one computer which is called the central computer.

16. Disadvantages of Installing a Network:
 Expensive to install
Although a network will generally save money over time, the initial costs of installing a network is
high.
 Requires administrative time
Proper maintenance of a network requires considerable time and expertise.
 File server may fail
If the file server “goes down” or does not work the entire network may stop working.
 Cables may break
A broken cable can stop any exchange of information in the network.
 Security issues
Security can be an issue with wireless networks i.e., hacking and installing viruses.

17.  What is a Protocol?
A protocol is a set of rules that manages the
communication between computers on a network.
 What is a Network Operating System?
Unlike Windows that are used for single computer
Networking Operating System (NOS) coordinate the
activities of multiple computers across the network.