Computer Networks: Types of networks – Network Topologies – Introduction to Internet - Internet Concepts - E-Mail - WWW Concepts - Web Browser- Search Engine - Finding websites for Recipes - How to applying for job using job web sites. 

1. SUBJECT : COMPUTER APPLICATION IN ECONOMICS
UNIT - II
NETWORK AND INTERNET
DR.M.MADHAVAN
ASSISTANT PROFESSOR OF ECONOMICS

2. UNIT - II
Computer Networks:
Types of networks – Network Topologies –
Introduction to Internet
- Internet Concepts - E-Mail - WWW Concepts - Web Browser- Search
Engine - Finding websites for Recipes - How to applying for job using job
web sites.
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 2

3. NETWORK
 The network is two or more connected
computer which can share resource like a
printer, an internet connection, application, etc.
 It is a collection of computer systems and
devices which are linked together using a
wireless network or via communication devices
and transmission media.
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 3

4. INTERNET
The internet is a global system which use TCP/IP protocol
suite to link various types of electric devices worldwide.
The internet is a collection of interconnected devices which
are spread across the globe.
It is a network of networks that consist of public, private,
sales, finance, academic, business and government networks.
The internet is a type of network and called as network of
networks.
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 4

5. COMPUTER NETWORK
A computer network is a set of connected computers.
Computers on a network are called nodes.
Computers can be connected via cabling, most
commonly the Ethernet cable or fibre optic cable.
Connections can also be wireless; you’ll hear the term
wi-fi to describe information sent via radio waves.
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 5

6. TYPES OF NETWORKS
LAN (LOCAL AREA NETWORK) MAN (METROPOLITAN AREA
NETWORK)
WAN (WIDE AREA NETWORK)
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 6

7. LAN (LOCAL AREA NETWORK)
 LAN is a network that connects a small number
of the system in a relatively close geographical
area. E.g., a floor or nearby surrounding of a
building.
This Photo by Unknown Author is licensed under CC BY-SA
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 7

8. MAN
(METROPOLITAN
AREA NETWORK)
IT IS A COMMUNICATION
INFRASTRUCTURE THAT HAS
BEEN DEVELOPED IN AND
AROUND LARGE CITIES.
This Photo by Unknown Author is licensed under CC BY-SA-NC
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 8

9. WAN (WIDE AREA NETWORK)
 It is a network that connects two or more local-
area networks over a large geographic
distance. A WAN spans across a large
geographic area, such as a state, province or
country.
This Photo by Unknown Author is licensed under CC BY-SA
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 9

10. TYPES OF NETWORK CONNECTIONS
a. Star Topology b. Bus Topology c. Ring Topology
 Computer networks can be broken down
historically into topologies, which is a technique
of connecting computers.
 The most common topology today is a star
topology.
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 10

11. TYPES OF
NETWORK
CONNECTIONS
(CONTD … …)
This Photo by Unknown Author is licensed under CC BY-SA
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 11

12. THE
INTERNET
This Photo by Unknown Author is licensed under CC BY-SA
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 12

13. THE INTERNET
 The Internet is a worldwide network of computer networks
that connects universities, government, commercial, and
other computers in over 150 countries.
 There are thousands of networks, tens of thousands of
computers, and millions of users on the Internet, with the
numbers expanding daily.
 Using the Internet, you can send electronic mail, chat with
colleagues worldwide, and obtain information on a wide
variety of subjects.
This Photo by Unknown Author is licensed under CC BY-SA
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 13

14. PRINCIPLE USE OF INTERNET
 Electronic mail.
 USENET newsgroups
 Information files.
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 14

15. ELECTRONIC MAIL
 Electronic mail, or e-mail, lets you electronically "mail" messages to users who have
Internet E-mail addresses. Delivery time varies, but it's possible to send mail across the
globe and get a response in minutes. LISTSERVs are special interest mailing lists which
allow for the exchange of information between large numbers of people.
 Short for electronic mail, e-mail or email is information stored on a computer
that is exchanged between two users over telecommunications.
 More plainly, e-mail is a message that may contain text, files, images, or
other attachments sent through a network to a specified individual or group of
individuals.
 The first e-mail was sent by Ray Tomlinson in 1971.
 Tomlinson sent the e-mail to himself as a test e-mail message, containing the
text "something like QWERTYUIOP." However, despite sending the e-mail to
himself, the e-mail message was still transmitted through ARPANET.
 By 1996, more electronic mail was being sent than postal mail.
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 15

16. USENET NEWSGROUPS
 USENET is a system of special interest discussion groups,
called newsgroups, to which readers can send, or "post" messages
which are then distributed to other computers in the network. (Think of
it as a giant set of electronic bulletin boards.)
 Newsgroups are organized around specific topics, for example,
alt.education.research, alt.education.distance, and
misc.education.science.
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 16

17. INFORMATION FILES
 Government agencies, schools, and universities, commercial
firms, interest groups, and private individuals place a variety of
information on-line.
 The files were originally text only, but increasingly contain pictures and
sound.
This Photo by Unknown Author is licensed under CC BY-SA
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 17

18. CLIENTS AND SERVERS
 Internet resources -- information and services -- are provided through
host computers, known as servers. The server is the computer system
that contains information such as electronic mail, database information,
or text files.
 As a customer, or client, you access those resources via client programs
(applications) which use TCP/IP to deliver the information to your
screen in the appropriate format for your computer.
 One important kind of client program is called a browser, which is
used to search through information provided by a specific type of
server. A browser helps you view and navigate through information on
the Internet.
 Today's most popular browsers, including Google Chrome, Mosaic(R),
Netscape(TM) Navigator, and the Microsoft Internet Explorer offer a
graphical interface to the World Wide Web.
This Photo by Unknown Author is licensed under CC BY-NC-ND
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 18

19. WEB BROWSER
 A web browser (commonly referred to as a browser) is a
software application for accessing information on the
World Wide Web.
 When a user requests a web page from a particular
website, the web browser retrieves the necessary content
from a webserver and then displays the page on the user's
device.
 Web - Browser Types
 Internet Explorer.
 Google Chrome.
 Mozilla Firefox.
 Safari.
 Opera.
 Konqueror
 Lynx
This Photo by Unknown Author is licensed under CC BY-SA-NC
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 19

20. SEARCH ENGINE
 A search engine is a web-based tool that enables users to locate information on the
World Wide Web.
 Popular examples of search engines are Google, Yahoo!, and MSNSearch. ...
The information gathered by the spiders is used to create a searchable index of the
Web.
 Top 10 Search Engines in the World in 2020
 The Best Search Engine in The World: Google.
 #2. Bing.
 #3. Baidu.
 #4.Yahoo!
 #5. Yandex.
 #6. Ask.
 #7. DuckDuckGo.
 #8. Naver.
 #9. AOL
 #10. Seznam
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 20

21. APPLYING JOBS USING JOB SITES
 To apply for a job online and to
complete online job applications,
you'll need Internet access, an email
address to use for job searching,
an up-to-date resume which
includes your employment history,
and your availability to work if
you're applying for a part-time job.
Whenever you apply for a job
you need to have proper covering
letter along with the application.
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 21

22. manimadhavan@gmail.co
m
This Photo by Unknown Author is licensed under CC BY-NC-ND
DR.M.MADHAVAN, DEPARTMENT OF ECONOMICS, ARIGNAR ANNA GOVERNMENT ARTS COLLEGE, NAMAKKAL 22