Basics of Internet and WWW

1. Internet and WWW
By:- Sagar Rai P
II Msc Computer Science
St Philomena PG Centre, Puttur

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History of Internet
1972 Telnet developed as a way to connect
to remote computer
1973 Email introduced, ARPANET goes
international and File Transfer
Protocol (FTP) established.
1984 Domain Name Server introduced
which allows naming of hosts, no
longer numeric
1986 NSFNET created
1991 Tim Berners-Lee releases World
Wide Web
1993 Mosaic (becomes Netscape) designed
by graduate students at University of
Illinois

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The Internet
Internet is an massive network of networks. It is essentially an
interconnection between millions of smaller computer
networks scattered around the globe. These networks are
connected with each other by the means of over ground
cables, underground cables, satellite links and sub-oceanic
cables etc.,
The word “ Internet” actually refers to all the hardware
infrastructure present in the network. Such hardware include
computer systems, routers, cables, bridges, servers, cellular
towers, satellites and other pieces.
All these pieces of hardware operated under the Internet
Protocol(IP).

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5. Vinton Cerf
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Father of Internet
Co-designer of the TCP/IP
networking protocol.

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WWW( World Wide Web)
The WWW is the collection of all the information that is
available in the Internet. So all the text, images, audio, videos
online- all this forms the WWW.
Most of these information is accessed through websites and we
identify websites by their domain names.
There is huge amount of information available in the WWW.
Only a tiny part of this information is searchable through
popular search engines like Google.
WWW uses htttp protocol to access the information from
various servers.

7. Tim Berners-Lee
Father of W W W.
The inventor of HTML.
Invented WWW while
working at CERN, the
European Particle Physics
Laboratory.
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8. Difference between Internet and WWW.
Internet WWW
Internet originated sometimes in late
1960’s
English scientist Tim Berners-Lee
invented the WWW in 1989
Nature of Internet is hardware Nature of WWW is software
Internet consists of Computers, Routers,
Cables, Bridges, Servers, Cellular towers.
WWW consist of information like text,
image, audio, video.
The first version of Internet was known as
ARPANET
In the beginning the WWW was know as
NSFNET
Internet works on basis of Internet
Protocol(IP).
WWW works on basis of Hyper Text
Transfer Protocol(HTTP).
Internet is independent of WWW. WWW requires internet to exist.
Internet is superset of WWW. WWW is subset of the Internet. Apart
from supporting WWW, the Internet
infrastructure is used for other things as
well(eg. FTP, SMTP).
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9. Internet Map
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10. How to access the Internet?
To access the Internet, an existing network need to pay a
small registration fee and agree to certain standards
based on the TCP/IP (Transmission Control
Protocol/Internet Protocol) reference model.
Each organization pays for its own networks and its own
telephone bills, but those costs usually exist independent
of the internet.
The regional Internet companies route and forward all
traffic, and the cost is still only that of a local telephone
call.
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11. How to access the Web?
Once you have your Internet connection, then you need special
software called a browser to access the Web.
Web browsers are used to connect you to remote computers,
open and transfer files, display text and images.
Web browsers are specialized programs.
Examples of Web browser: Netscape Navigator (Navigator)
and Internet Explorer.
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12. Client/Server Structure of the Web
Web is a collection of files that reside on computers,
called Web servers, that are located all over the world
and are connected to each other through the Internet.
When you use your Internet connection to become part
of the Web, your computer becomes a Web client in a
worldwide client/server network.
A Web browser is the software that you run on your
computer to make it work as a web client.
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13. Client/Server Structure of the Web
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14. Web Browser
A web browser is a software application used to locate,
retrieve and display content on the world wide web including
web pages, images, video and other files.
As a client/server model the browser is the client run on a
computer that contacts the web server and requests
information,
The Web Server sends the information back to the browser
which displays the results on the computer or other Internet
enabled device that supports a browser.
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15. Commonly used Web Browser
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16. Web Page
A document which can be displayed in a web browser such as
Google Chrome, firefox. These are also called as “Web pages”
or “pages”.
A Web page is accessed by entering a URL address and may
contain text, graphics and hyperlinks to other Web pages and
files.
Once in a browser, you can open a webpage by entering the
URL in the address bar.
For example, typing http://www.computerhope.com/esd.html
opens the Computer hope’s esd page.
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17. Website
A collection of Web pages which are grouped together and
usually connected together in various ways. Often called a
“Web site” or simply a “site”.
A Website is a central location of various web pages that are
all related and can be accessed by visiting the home page using
a browser.
For example, our college website spcputtur.org which contains
number of WebPages.
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18. Web Server
Web servers are software applications running on Web sites
that handle requests from Web browsers.
Servers "serve up" Web pages to a Web browser.
Web server software returns Web pages (including pictures,
audio and possibly video), encoded in HTML, back to their
Web browser clients.
More importantly, Web servers can capture information from
users and start up other server-resident programs. This opens
the door to accessing corporate databases and legacy COBOL
applications from the Web.
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19. Types of Web Server
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20. HTML
In 1980, Physicist Tim Berners-Lee introduced HTML
language.
It is the authoring language used to create documents on the
World Wide Web.
HTML defines the structure and layout of a web document by
using a variety of tags and attributes.
HTML is the standard markup language for creating web
pages and web applications.
HTML elements are the building blocks of HTML pages.
With HTML constructs, images and other objects, such as
interactive form can be embedded into the rendered page.
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21. Structure of HTML code
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22. Example For HTML Code
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24. IP Address
The combination of the four IP address parts provides 4.2
billion possible addresses (256 x 256 x 256 x 256).
This number seemed adequate until 1998.
Members of various Internet task forces are working to
develop an alternate addressing system that will accommodate
the projected growth.
However, all of their working solutions require extensive
hardware and software changes throughout the Internet.
Example for IP address: 192.168.9.1
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25. Domain Name System
Most web browsers do not use the IP address t locate
Web sites and individual pages.
They use domain name addressing.
A domain name is a unique name associated with a
specific IP address by a program that runs on an
Internet host computer.
This program, which coordinates the IP addresses and
domain names for all computers attached to it, is called
DNS (Domain Name System ) software.
The host computer that runs this software is called a
domain name server.
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26. Domain Name System
Domain names can include any number of parts separated by
periods, however most domain names currently in use have only
three or four parts.
Domain names follow hierarchical model that you can follow from
top to bottom if you read the name from the right to the left.
For example, the domain name gsb.uchicago.edu is the computer
connected to the Internet at the Graduate School of Business (gsb),
which is an academic unit of the University of Chicago (uchicago),
which is an educational institution (edu).
No other computer on the Internet has the same domain name.
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27. Structure of a Uniform Resource Locators
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28. Uniform Resource Locator
Is defined as the global address of document and other
resource on the WWW.
URL is an address that sends users to a specific resource
online, such as webpage, video other document or resource.
A URL is one type of Uniform resource identifier (URI); the
generic term for all types of names and addresses that refer to
objects on the WWW.
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30. HTTP
Is an application protocol for distributed, collaborative,
hypermedia information systems.
The transfer protocol is the set of rules that the
computers use to move files from one computer to
another on the Internet.
The most common transfer protocol used on the Internet
is the Hypertext Transfer Protocol (HTTP).
Two other protocols that you can use on the Internet are
the File Transfer Protocol (FTP) and the Telnet Protocol
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31. Difference between HTTP & HTTPs
HTTP HTTPS
1) URL begins with “http://” 1) URL begins with “https://”
2) It uses port 80 for communication 2) It uses port 443 for communication
3) Unsecured 3) Secured
4) Operates at application layer 4) Operates at transport layer
5) No encryption 5) Encryption is present
6) No certificates required 6) Certificate Required.
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