Internet, Intranet &
Extranet
Rashedul Hasan
Internet-What is it……
► Network
of the Networks.
► Network of Computers linking many
different types of computer all over the
world.
► The Internet is a global system of
interconnected computer networks that
interchange data by using the standardized
Internet Protocol (TCP/IP).
Networks And Data Communications
Visualization of the various routes through a portion of
the Internet.
History
► The
Internet has its root in the ARPANET system
of the Advanced Research Project Agency of the
U.S department of Defense.
► ARPANET was the first WAN and had only 4 sites
in 1969.
► Internet evolved from basic ideas of ARPANET.
► In 1989 the U.S. Govt. lifted restriction on use of
the Internet and allowed it to be used for
commercial purposes as well.
Now……
It has interconnects more
than 30,000 networks.
► Allowing more than 10
million computers
► More than 50 million users
► In more than 150
countries around the globe
to communicate each
other.
► It continues to grow up at
a rapid pace.
►
The Server
Growth of the Internet
100000000
10000000
1000000
100000
10000
1000
Aug-01
Aug-99
Aug-97
Aug-95
Aug-93
Aug-91
Aug-89
Aug-87
Aug-85
Aug-83
100
Aug-81
Number of Hosts on the Internet
1000000000
Source: Internet Software Consortium
Users….
► By
region, 40% of the world's Internet users
are based in Asia,
► 26% in Europe,
► 17% in North America,
► 10% in Latin America and the Caribbean,
4% in Africa,
► 3% in the Middle East
► and 1% in Australia.
Language….
► The
prevalent language for communication on the
Internet is English.
► After English (30% of Web visitors) the most
requested languages on the World Wide Web are
Chinese (17%),
► Spanish (9%),
► Japanese (7%),
► French (5%)
► and German (5%).
Governing Bodies…
► Because
the Internet is a distributed network
comprising many voluntarily interconnected
networks, the Internet has no governing body.
► ICANN's role in coordinating the assignment of
unique identifiers distinguishes it as perhaps the
only central coordinating body on the global
Internet, but the scope of its authority extends
only to the Internet's systems of domain names,
IP addresses, protocol ports and parameter
numbers.
Governing Bodies…
►
The Internet
Corporation for
Assigned Names and
Numbers (ICANN) is the
authority that coordinates
the assignment of unique
identifiers on the Internet,
including domain names,
Internet Protocol (IP)
addresses, and protocol
port and parameter
numbers
ICANN headquarters in
Marina Del Rey, California,
United States
Common uses
► The
Internet carries various information resources
and services, such as
► electronic mail,
► online chat,
► file transfer and file sharing,
► online gaming,
► and the inter-linked hypertext documents and
other resources of the World Wide Web (WWW).
► Social Networking
Current Uses of Internet
Electronic Mail
► With
an Internet email account, users can
communicate with anyone else on-line, any
place in the world, with no long distance
fees. Email can also be used to join mailing
lists, bulletin boards, or discussion groups
that cover a huge variety of subjects.
Current Uses of Internet
World Wide Web.
► The
World Wide Web is not a physical place,
not a set of files, nor even a network of
computers. The heart of the WEB lies in the
protocols (common communication rules
and languages) that define its use. The
WWW uses hypertext transfer protocols
(http) to transport files from one place to
another.
World Wide Web.
► "By
using standardized software, today
users can navigate through most features of
the Internet, including text data such as
email, photo-image files, and video and
audio clips.”
World Wide Web.
► HTML
(HyperTextMarkup Language), the written
code that creates Web pages and links, is a
language that all computers can read, so
computers with varying operating systems (such
as Windows and Macintosh) can communicate
easily.
► JAVA, a HTML compatible language developed by
Sun Microsystems in the mid 1990s, is also
universally readable by computers and allows
small interactive programs to run on Web pages,
creating moving graphic elements such as threedimensional animations
Current Uses of Internet
Internet chat, Social networking
►
►
Internet chat and instant messaging systems allow
people to stay in touch in a convenient way while
working at their computers. Messages can be sent
and received instantly. In addition, these systems
also allow file transfer, as well as voice and video
contact.
Social networking websites allow people to stay in
touch with friends and family, and knowing their
activities by viewing their profiles. The concept of a
social networking website is to store people’s
profiles and connecting them between one and
another. A personal profile can include pictures and
videos to be shared.
Current Uses of Internet
VoIP
► VoIP
(Voice over Internet Protocol) started from
an optional two-way voice chat provided by some
of the instant messaging systems that started
around the year 2000. The benefit of VoIP is that
it can be free or cost much less than a normal
telephone call, because the Internet carries that
voice traffic.
► VoIP is surely a cheap solution for long distance
call.
Business Use
► Faster
means of communication:
with the help of E-mail business can stay in
touch worldwide with its customer, suppliers
and regularities bodies. It can also help in
making inexpensive phone call through VoIP
and have teleconferencing.
Provide product information
► It
allows customer direct access to
information about company’s products.
Some people prefer to learn about products
on their own. The Internet has an
incomparable ability to make information
about a company's products or services
available to potential customers. It also
provides the information whenever the
customer wants it.
Save on literature costs
► Providing
the information online reduces the
need to print and mail product literature,
thereby resulting in significant cost
reductions
Business Use
► Product
Advertising & Promotion:
Internet become a very effective but cheap
medium of advertisement and promotion.
Web sites can be used to provide
information on new product, recent strategic
alliance, press release and other related
information of potential interest to existing
and prospective customers.
Ex. www.singer.com.bd
Online advertising is booming,
because…
► Reach
a worldwide audience. The Internet is a
worldwide network allowing the advertiser to reach
people even very expensive advertising could not.
► WWW
popularity (graphics, sound, motion). Exciting
graphics, sound and even motion can promote and
display products, representing a huge advance over
the useful but static information available for early
email commerce. The Web’s ease of use and instant
links to related products and ordering instructions
has allowed consumers to respond immediately to
online advertising.
Online advertising is booming,
because…
Encryption (security for credit and bank card). By
the mid 1990s, trustworthy encryption (coding and
decoding) technologies made the online use of
credit and bank card numbers, addresses, social
security numbers and other sensitive information
safer for both seller and buyer. (note: safer, not
necessarily completely safe).
► Global marketers seek an alternative to television.
► Dozens of start ups want to make a splash in online
commerce; their business plans practically force
them to buy Internet ads.
► Online world is accommodating advertisers in ways
that print and broadcast media would find
impossible.
►
Business Use
► Feedback
about Product:
Business also use the internet to gather
information about user satisfaction of
existing product, market opportunity of a
new product etc.
Human Resource Issues:
Business can now accept resume/CV
through online and can even interview
online. Many companies provide current
information about job openings and
attract talented people from places
they could not reach otherwise.
www.bdjobs.com
www.prothom-alojobs.com
Business Use
► Customer
Support Service:
Many businesses use the internet to provide timely
and quick customer services.
► Online Shopping:
internet also facilitate the introduction of a new
market concept consisting of virtual shops. These
shops remain open 24 hours all the year round
and make sales happen through internet.
[WWW.amazon.com]
Let customers try a sample of
your product or service
► Many
new Web tools are becoming available
that will allow consumers to try out a
sample of what the company have to offer
before they buy. Gain a competitive
advantage by offering a "test drive" of your
product or service. For example, Test a
software applications before you buy them.
Internet connection
►
Telephone (Dial-up) Modem:
Dial up networking technology provides PCs and
other network devices access to a LAN or WAN via
standard telephone lines.
low speed but cheap & widely available.
A 6 minute long music video takes 4 hours 45 minutes to
be downloaded from WWW with a 28.8 kbps modem.
Modem Stands for Modulator and Demodulator.
Modulate: Converts digital signals to analog form
Demodulate: Converts analog signals back to digital form.
Internet connection
because telephone lines have traditionally been
analog, we need to use modem if our computer is to
send signals over a telephone line. The modem
converts the computer’s digital signals into
telephone line’s analog signals and analog signals
back into digital signals.
Modem means Modulator demodulator.
Modems are rated by their speed in moving data
from the computer to the telephone line. This
speed is measured in bits per second
(bps). Standard modern modems are rated at
28,800 bps, 33,600 bps and 56,400 bps.
Networks And Data Communications
High Speed phone line
►:
ISDN
ISDN stands for Integrated Services Digital
Network. It is consists of hardware and software
that allows data to be transmitted over traditional
telephone wire.
A 6 minute long music video takes 1 hour to be
downloaded from WWW.
: DSL
Digital Subscriber line. Incoming data are faster
then outgoing data. A 6 minute long music video
takes 11 minutes to be downloaded from WWW.
Cable Modem
wireless connection
►A
cable modem connects a PC to a cable-TV
system that offers an internet connection.
► Wireless system :
it includes satellite based radio link connection,
Wifi connection etc.
ISP: Internet Service Provider: A company that
connect you through your communication line to
its server, which connect you to the internet via
another company’s network access point.
Simplified Communications
Model - Diagram
How the Internet Works
How the Internet Works
Here's what happens to a piece of data (eg. a Web page)
when it is transferred over the Internet:
►
►
►
It is broken up into a whole lot of same-sized pieces
(called packets).
A header is added to each packet that explains where it
came from, where it should end up and how it fits in with
the rest of the packets.
Each packet is sent from computer to computer until it
finds its way to its destination. Each computer along the
way decides where next to send the packet. This could
depend on things like how busy the other computers are
when the packet was received. The packets may not all
take the same route.
How the Internet Works
► At
the destination, the packets are examined. If
there are any packets missing or damaged, a
message is sent asking for those packets to be
resent. This continues until all the packets have
been received intact.
► The packets are reassembled into their original
form.
► Each computer connected up to the Internet has
software called TCP/IP (Transmission Control
Protocol/Internet Protocol) which is responsible for
receiving, sending and checking packets. TCP/IP is
the 'glue' of the Internet.
E-mail
► www.mail.yahoo.com
► www.gmail.com
► www.hotmail.com
hasan.rashed@gmail.com
hasan.rashed = User ID [identifies who is at the
address]
gmail = domain [a location on the internet]
.com = top level domain.
.bd = identifies the name of the country.
Top level domain
Domain
.biz
.com
.edu
.gov
.info
.int
Mil
.net
.org
Description
Business
Commercial
Educational & Research
institute
Government
Information
International Organization
Military Organization
network
Non-profit & Professional
organization
E-mail
► Electronic
Mail.
► Internet e-mail messages consist of two major
sections:
► Header — includes sender, receiver, and other
information about the e-mail
► Body — The message itself as unstructured text;
sometimes containing a signature block at the end
www.mail.yahoo.com
www.gmail.com
www.hotmail.com
Header fields
► The
message header usually includes at least the
following fields:
► To: The e-mail address [es], and optionally name
[s] of the message's recipient [s]
► CC : Carbon copy, for copying message to others.
► Bcc: Blind Carbon Copy, for copying others without
the primary recipient knowing it.
► Subject: A brief summary of the contents of the
message
► Attachment
Large file, music video or MP3 music can be
attached and send to the destination
address.
Spamming
► Spamming
is unsolicited commercial e-mail.
► Because of the very low cost of sending e-mail,
spammers can send hundreds of millions of e-mail
messages each day over an inexpensive Internet
connection which may results in information
overload for many computer users who receive
huge unsolicited email each day
Email Spoofing
► Email
spoofing is a kind of forgery. Mails
appear to be sent from a known sender but
they are actually not so. Spoofing involves
forging the email headers, by altering the
header information
Email Bombing
► It
refers to transferring a huge amount of
emails to victim, ensuing the victim's email
account crash. An easy way of attaining this
would be to subscribe the victim's email
address to a huge number of mailing lists.[
Online chat
► Online
chat can refer to direct one-on-one
chat or text-based group chat using tools
such as instant messengers, Internet Relay
Chat, talkers etc.
Software
► Windows
Live Messenger
► Yahoo! Messenger
► Google Talk
► Internet Relay Chat (IRC)
► ICQ (OSCAR)
► Pal talk
WWW & Web Browser
WWW: World Wide Web.
► Web Browser: is a software that enables users to view
web pages and to jump from one page to another.
► Internet Explorer is the mostly widely used web browser.
► Usage share for Q4 2008
► Internet Explorer: 70.72%
► Firefox: 20.27%
► Safari: 6.77%
► Chrome: 0.78%
► Opera: 0.73%
► Netscape: 0.48%
► Other: 0.24%
►
► URLs:
Uniform Resource Locator.
It is the web site’s address.
http://www.nps.gov/yose/camping.htm
http://= protocol, stands for Hyper Text
Transfer Protocol.
It is a set of communication rules for
exchanging information. It allows brewers
to connect with web server.
► www.nps.gov
= web server name. it is the
particular computer on which this web site
is located.
► Yose/ = the directory name. it is the name
on the server for the directory or folder from
which the browser needs to pull the file.
► Camping.htm = file name. the particular
page or document that you are looking for.
Web Browser
Web Browser
Web Browser
Web Browser
Web Browser
Web Browser
Web Site, Web page & Web
Portals
►
►
►
Web Site is the location of a web domain name in a
computer somewhere on the internet. It is actually a
collection of web pages, images, videos or other digital
assets that is hosted on one or more web servers, usually
accessible via the Internet. On the other hand,
Web page is document on the WWW that can include
text, picture, sound and video. The first page we see at a
website is like the title page of a book. This is the Home
Page, or welcome page, which identifies the web site and
contains links to other pages at the site.
Web Portals is the website that group together in one
convenient location popular features such as search tools,
e-mail, and electronic commerce and discussion group etc.
portal can be customized to fit user’s interest. The most
popular portal are YAHOO, MSN, EXCITE Network etc.
Web portal & Search engines
► Web
portal: www.yahoo.com
► Web sites that group together in one
location.
► Search engine: www.google.com
► It allows us to find specific documents
through keyword search.
From the Internet to intranets
and extranets
‘Intranet’ and ‘extranet’ are two terms that arose in the 1990s
to describe applications of Internet technology with specific
audiences rather than anyone with access to the Internet. Access
to an intranet is limited by username and password to company
staff, while an extranet can only be accessed by authorized third
parties such as registered customers, suppliers and distributors. An
extranet permits access to trusted third parties and the Internet
provides global access. Extranets provide exciting opportunities to
communicate with major customers since tailored information such
as special promotions, electronic catalogues and order histories
can be provided on a web page personalized for each customer. As
well as using the Internet to communicate with customers,
companies find that internal use of an intranet or use of an
extranet facilitates communication and control between staff,
suppliers and distributors. Second, the Internet, intranet and
extranet can be applied at different levels of management within a
company.
From the Internet to intranets
and extranets
►
►
Intranet
A network within a single company that enables access to
company information using the familiar tools of the
Internet such as email and web browsers. Only staff within
the company can access the intranet, which will be
password-protected.
Extranet
Formed by extending the intranet beyond a company to
customers, suppliers, collaborators or even competitors.
This is again password protected to prevent access by
general Internet users.
From the Internet to intranets
and extranets
www.yahoo.com
web portal.
B
A
W
Babel Fish Translations
Account Information
Weather
Bix
Address Book
Web Hosting
Bookmarks
Alerts
Widgets
Buzz
Alibaba
Wireless
Answers
Women
Z
Audio Search
Zimbra
C
Autos
Calendar
Avatars
Chat
Company Info
Y
Creative Commons Search
Yahoo! for Good
Yahoo! Search Blog
Yellow Pages
Search engine
Movies
Pak & Indian MP3 Song
www.avg.com
www.avast.com
www.prothom-alojobs.com
www.monster.com
www.flickr.com
www.youtube.com
► www.facebook.com
► www.hi5.com
► www.myspace.com
www.prothom-alo.com
www.eprothom-alo.com
► www.cellbaazar.com
► www.wikipedia.com
Terminologies
►A
network server is a computer designed
to process requests and deliver data to
other (client) computers over a local
network or the Internet.
► Web servers
► proxy servers
► FTP servers
► online game servers
Terminologies
► Proxy
Servers : A proxy server acts an
intermediate gateway between you and
your Internet connection.