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UNIT 3
Introduction to the Internet
and Web

Internet
? It is the largest network in the world that connects
hundreds of thousands of individual networks all
over the world.
? The popular term for the Internet is the
“information highway”.
? Rather than moving through geographical space, it
moves your ideas and information through
cyberspace – the space of electronic movement of
ideas and information.

Internet
? No one owns it
? It has no formal management organization.
? As it was originally developed by the Department
of defense, this lack of centralization made it less
vulnerable to wartime or terrorist attacks.
? 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) .

The uses of the Internet
? Send e-mail messages.
? Send (upload) or receive (down load) files
between computers.
? Participate in discussion groups, such as
mailing lists and newsgroups.
? Surfing the web.

What is Web?
? The Web (World Wide Web) consists of information
organized into Web pages containing text and graphic
images.
? It contains hypertext links, or highlighted keywords
and images that lead to related information.
? A collection of linked Web pages that has a common
theme or focus is called a Web site.
? The main page that all of the pages on a particular
Web site are organized around and link back to is
called the site’s home page.

How to access the Internet?
? Many schools and businesses have direct
access to the Internet using special high-
speed communication lines and equipment.
? Students and employees can access through
the organization’s local area networks
(LAN) or through their own personal
computers.
? Another way to access the Internet is
through Internet Service Provider (ISP).

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.

Internet Service Provider (ISP)
? A commercial organization with permanent
connection to the Internet that sells
temporary connections to subscribers.
? Examples:
? Prodigy, America Online, Microsoft
network, AT&T Networks.

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.

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.

Hypertext Markup Language
(HTML)
? The public files on the web servers are ordinary
text files, much like the files used by word-
processing software.
? To allow Web browser software to read them,
the text must be formatted according to a
generally accepted standard.
? The standard used on the web is Hypertext
markup language (HTML).

Hypertext Markup Language (HTML)
? HTML uses codes, or tags, to tell the Web browser
software how to display the text contained in the
document.
? For example, a Web browser reading the following line of
text:
 A Review of the BookWind Instruments of
the 18th Century
? recognizes the and tags as instructions to
display the entire line of text in bold and the and 
tags as instructions to display the text enclosed by those
tags in italics.

Addresses on the Web:IP Addressing
? Each computer on the internet does have a
unique identification number, called an IP
(Internet Protocol) address.
? The IP addressing system currently in use on
the Internet uses a four-part number.
? Each part of the address is a number ranging
from 0 to 255, and each part is separated from
the previous part by period,
? For example, 106.29.242.17

IP Addressing
? 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.

Domain Name Addressing
? 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.

Domain Name Addressing
? 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.

Uniform Resource Locators
? The IP address and the domain name each identify a particular
computer on the Internet.
? However, they do not indicate where a Web page’s HTML
document resides on that computer.
? To identify a Web pages exact location, Web browsers rely on
Uniform Resource Locator (URL).
? URL is a four-part addressing scheme that tells the Web
browser:
? What transfer protocol to use for transporting the file
? The domain name of the computer on which the file resides
? The pathname of the folder or directory on the computer on
which the file resides
? The name of the file

Structure of a Uniform Resource Locators
http://www.chicagosymphony.org/civicconcerts/index.htm
protocol
Domain name
pathname
filename
http => Hypertext Transfer Protocol

HTTP
? 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

How to find information on the Web?
? A number of search tools have been developed and
available to you on certain Web sites that provide
search services to help you find information.
? Examples:
? Yahoo ? www.yahoo.com
? Excite ? www.excite.com
? Lycos ? www.lycos.com
? AltaVista ? www/alta-vista.com
? MSN WebSearch ? www.search.msn.com

How to find information on the Web?
? You can find information by two basic means.
? Search by Topic and Search by keywords.
? Some search services offer both methods, others only
one.
? Yahoo offers both.
? Search by Topic
You can navigate through topic lists
? Search by keywords
You can navigate by entering a keyword or phase into
a search text box.

Chat
? Chat is a program that enables you to
communicate with others in real-time
through messages.
? The user can log on to certain websites and
communicate with various other users
online by using Internet chat software.
? Chat software is interactive software that
allows user to type comment in one window
and receive replies in another from someone
who is accessing the same software.

Instant messaging
? (IM) is a form of communication over the Internet
that offers an instantaneous transmission of text-
based messages from sender to receiver.
? IM software is widely used for personal and
commercial use. Some instant messaging software
allows users to view messages received when they
are not logged on. These are called “Offline
Messages”.

Instant Messaging
Features of an instant messaging are as
follows:
? Text Messages can be sent to one or more person (Similar
to SMS)
? Audio calling and conferencing.
? Video calling and conferencing.
? File transfers (Not limited to documents, spread sheets,
audio files, video files, etc.)
? Message history (Save messages for future reference).

Instant Messaging
? Application based and Web based.
Application based instant messaging software is
downloaded and installed on user’s computer.
Some of the popular instant messaging software are:
? Google Talk
? Yahoo! Messenger
? Skype
? Windows Live Messenger
? Rediff Bol, etc.

Instant Messaging
? Web based instant messaging software is accessed
using browsers such as Internet Explorer, Mozilla
Firefox, Google Chrome, etc.
Some of the popular web based instant messaging
software are:
? Meebo
? Yahoo! Messenger for the Web
? MSN Web Messenger
? IMO
? Facebook

Advantages
1. Photos can be sent using an instant messaging.
2. Emotions can be expressed easily when
communicating with a person.
3. It is almost same as talking to someone face-to-
face.
4. You can also chat in a group.
5. It makes it possible for user to keep in contact and
chat to each other even if, they are in different
countries without having to pay a lot of money.

Disadvantage
1.Viruses can be easily spread via texting.
2.Children tend to spend more time in
chatting with friends instead of bonding
with their family and studies.

Email
? It is an electronic version of sending and
receiving letters.
? The E-mail is transmitted between computer
systems, which exchange messages or pass
them onto other sites according to certain
Internet protocols or rules for exchanging E-
mail

Email
? . You can send E-mail from your computer
at anytime to any address around the world
and your electronic letter or E-mail will
arrive at its destination in seconds after you
send it, even if the receiver is not online.

Email
? or sending and receiving an E-mail, you
must have an E-mail account, which is
either a Web based online E-mail account or
an E-mail account on your ISP server.
? Web based online E-mail account can be
created through many sites like Gmail,
Yahoo mail, Rediffmail etc.

Elements of E-mail Account
? Some important elements or folders that are used
to organise your E-mail messages are as follows:
Inbox It contains all incoming messages.
Outbox The message is stored in the outbox
until, it is successfully sent to the recipient.
Sent mail It contains all sent messages.
Draft It contains the draft messages, which
are ready to be sent.
Trash It contains deleted messages.
Spam It contains junk E-mails.

Email
? Formats of an E-mail Message
There are two formats of an E-mail message,
which are as follows:
1. Plain text (txt) E-mail It can be read by anyone
type of E-mail application. It does not support text
formatting options Such as bold, italic, colored
fonts etc. It can have attached pictures or graphics,
but they can not be inserted.
2. Rich text (rtf) E-mail It cannot be read by any
type of E-mail application. It supports text
formatting options such as bold, italic, colored
fonts etc. Pictures or graphics can be inserted.

Email
Components Description
To This field contains the E-mail address of recipient.
Cc
Cc stands for Carbon copy. This contains the address of recipients to whom
you want to send a copy of an E-mail message. .
Bcc
Bcc stands for Blind carbon copy. This field also contains the list of
recipients. Bcc recipients can see the To and Cc addresses but Bcc
recipients name is not visible to others.
Subject This field contains the title of a message.
Body It includes text of an E-mail message.
Attachments You can attach any document with E-mail message.
Formatting Using the formatting tab, you can edit the message.
Other options
Other options like emoticons, bold, italic, hyperlinks etc, are used to make
message more interactive.
Send button You have to click the send button to send the mail.

Email
An example of the structure of an

Email
? Advantages of an E-mail
1. E-mail speeds up the workflow process,
documents can be sent for comments, corrections
can be made quickly.
2. E-mailing saves papers and printing costs.
3. Multiple copies of a message can be sent to a
group of people.
4. Messages can be prepared in advance and save
until you are ready to send them.
5. File and images can be attached to an E-mail.

Email
? Disadvantages of an E-mail
1.E-mail attachments can carry viruses.
2.Limited size of data file can be sent.
3.Hasty medium to convey emotions.
4.No guarantee that the mail will be read until
the user logs on and check E-mail.

VoIP
? Voice over Internet Protocol (VoIP), also called IP
telephony, is a method and group of technologies for the
delivery of voice communications and multimedia sessions
over Internet Protocol (IP) networks, such as the Internet.
? The terms Internet telephony, broadband telephony, and
broadband phone service specifically refer to the
provisioning of communications services (voice, fax, SMS,
voice-messaging) over the public Internet, rather than via
the public switched telephone network (PSTN), also
known as plain old telephone service (POTS).

VoIP
? A VoIP phone is necessary to connect to a VoIP
service provider. This can be implemented in
several ways:
? Dedicated VoIP phones connect directly to the IP
network using technologies such as wired Ethernet
or Wi-Fi. These are typically designed in the style
of traditional digital business telephones.

VoIP
? An analog telephone adapter connects to the network and
implements the electronics and firmware to operate a
conventional analog telephone attached through a modular
phone jack. Some residential Internet gateways and
cablemodems have this function built in.
? Softphone application software installed on a networked
computer that is equipped with a microphone and speaker,
or headset. The application typically presents a dial pad
and display field to the user to operate the application by
mouse clicks or keyboard input

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UNIT3- Internet(2).ppt

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