This is an introduction to the Internet for freshers in middle school and college.

1. L J Haravu

2. What are networks?
What is the Internet and how does it work?
What is the Worldwide Web (WWW)? How is it
different from the Internet?
What is needed to access the Web?
Important Web concepts
Content and services on the Internet

3. Whether we know it or not, we all belong to one or
more networks
Family – Friends – Professional – Bank – Telephone - TV -
Hobby – Religious, etc., etc.,
Network paradigms
Share and exchange data, information and knowledge
Share, exchange resources
Collaborate on common projects/interests
Inform, entertain
Computer networks are the infrastructure of the
Internet

4. A local area network or LAN
A collection of computers within a building or office
so that they can inter-communicate/share data,
information

5. Wide Area Network (WAN)
Connect computers across a wide geographical
area, e.g., between different branches of a
company in different parts of the country

6. It is a Network of Networks. Millions of networks –
LANs, WANs, individual devices using diverse telecom
networks connect to each other.
All the networks agree to use common rules to connect
to each other. These rules are called protocols
Protocols are based on a worldwide agreement of how to
represent/exchange/transmit information. TCP/IP
(Transmission Control Protocol/Internet Protocol) is a suite of
protocols fundamental to the Web
Internet software of all kinds conforms to the TCP/IP
Let’s see a Video of how the Internet works

7. The Internet is the medium or container or carrier
The Worldwide Web (WWW or Web) has the content
The Web provides the means to store, access,
communicate, retrieve information stored in millions of
networks all over the world in different languages
The Web is therefore also known as the Information
Superhighway
The Web is the intelligence behind the hardware of the
Internet. The intelligence behind the Web is from
human beings
It is not only an information network but also a
knowledge network

8. Depending on the need for speed of a connection (also
called Bandwidth) the options are:
Dial-up
Slowest. Must dial-up to a phone line to connect
Internet and phone cannot be used simultaneously
DSL or Digital Subscriber Line
Faster than Dial-up. Always on. Higher speeds of access.
Telephone and Internet can be used simultaneously
Cable
Uses the Cable TV connection. Can be as fast as DSL, but
security can be a problem
Wireless

9. Server
Client
Client Client
The Smart Class Facility at AVK will also be run as a Client-Server Facility

10. All networks including the Web are based on an
architecture of Servers and Clients
A Server is a special type of computer on the
network that provides one or more services to
clients computers on the network
A Client is also a computer which users have
access to on the network. The Client seeks
services from the Server and the Server
provides the services.

11. File Server
Database
Server
Email Server
Web Server
Internet
Remote Client

12. There are dedicated servers that are generally owned
by a web service provider, e.g., AVKs web site is
located on a web server in the US provided by a
company called GoDaddy
Web Servers are up and running 24 x 7 x 365 days
The Web Service Provider also called Hosting provider
provides the space, the software and maintenance of
the site, security of data
There are different types of servers: file, database,
application, e-mail, etc.

13. Every site belongs to a domain, e.g., the schools
domain name is acharyavidyakula.org. The
School pays to own this domain name
A page on the web site has an address called
the URL (Universal Resource Locator)
e.g., the URL for the Schools web site is
http://www.acharyavidyakula.org)
Once you know the URL of web sites/pages, these
can be accessed with software known as a web
browser, e.g., Internet Explorer, Firefox

14. The fundamental constituent of the Web is a
page
Pages that you see on a site are represented
using a language called HTML (hypertext markup
language)
An HTML page can have text, symbols, images,
video in it, e.g.,
http://www.acharyavidyakula.org/web/home
Not all pages of a site are static. Some of them
are created dynamically

15. The Process
A client machine connects to the Internet
Once connected, it requests a web site/page by
entering the URL in a browser
The request passes through a maze of routers,
switches, cables, satellite, cell phone towers, etc., and
until it reaches the Web server
The Web Server which is always ‘listening’ to requests,
receives the request. It knows the address from where
the request was received
The Web Server returns the page requested to the
client by its address
Software on the client computer displays the page

16. An important element of most web pages is
hypertext. This is specially formatted text.
The hypertext is meant to connect the user to
another page in the same site or to a page in some
other site. The link is called a hyperlink. Let’s see an
example
Hyperlinks can link to text, images, videos on one or
more web sites/pages
Some web pages have forms that can be filled
Many web pages have a search box, e.g., Google

17. The Web is undoubtedly a veritable mine or
repository of information. The following are a
few of the types of sites/content available:
Simple textual pages
Pages with more than just textual content
Database sites on various subjects
Email providers, e.g., gmail, yahoo, rediffmail
Sites of companies, banks, institutions, schools,
governments, international organizations,
universities, charitable organizations, etc., etc.
Library sites, e.g., SDM-IMD, Mysore

18. Digital libraries, e.g., The Hathi Trust, Google Books
Search engine sites, e.g., Google, Bing, Yahoo
Sellers, resellers of goods and services, e.g.
Amazon, Ebay – these are interactive sites
Travel Services such as travel agents, airline and
railway reservations, e.g., the reservation site for
Indian Railways
Reference Materials such as Encyclopedia’s,
dictionaries, directories
Learning resources
Courseware sites, e.g., MIT Open Courseware

19. Scholarly subject portals, e.g., University of
California
Tutorial Sites on different subjects, e.g., Health
Blogs
Wikis of different kinds
The best example of a WIKI is Wikipedia
Music sites to listen/download music, e.g.,
MusicIndiaonline
Photo publishing/sharing/downloading sites
Videos/Movies publishing/sharing/downloading
sites, e.g., Youtube
Social networking sites, e.g., Facebook

20. Exchange electronic mail (E-mail) with friends and colleagues
with accounts on the Internet
Post information for others to access, and update it
frequently
Search many types of general and specialized databases
Access and use many services online, e.g., railway
reservations, e-banking
Access/exchange multimedia information: audio,
photographic images and video, and
Be part of an online social network, e.g., Facebook, etc., etc.,
As a source of Infotainment
As a source of knowledge (experience exchange)
access diverse perspectives from around the world.

21. The Web is a bad influence on children
Prevent children from using the Internet
Workers waste time during office hours with
the Internet
The Web has made us stupid. We only copy and
paste and feel very great about it.