Transcript HCI Lecture 31 Internet and WWW.ppt

Introduction to
Internet and World
Wide Web
Lecture 31
By
Prof. Dr. Sajjad Mohsin
Today’s Outline

We will discuss today
 Basic
Networking Interfaces
 Internet
 World Wide Web
 Applications and Usage
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Terms & Definitions
Client
A client is the requesting program in a
client/server relationship, e.g, the user of a
Web browser is effectively making client
requests for pages from servers all over
the Web.
Terms & Definitions
Server
In general, a server is a computer
program that provides services to other
computer programs in the same or other
computers.
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Terms & Definitions
Web browser:
The web client, called a browser, is the
software that allows you to interact with
information available on the Internet. e.g
Netscape Navigator, Microsoft Internet
Explorer, MOSAIC.
Terms & Definitions
HTML (Hypertext Markup Language):
HTML is a tagging language used to compose
documents that will be viewed by a web browser.
It is a standard adopted so that no matter what
computer platform someone is using, the web browser
knows how to display the web document.
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Web Page:
A mixture of text, graphics, sound and animation in
the HTML format, to make information accessible in
a easy to understand format using the Internet.
Web Site:
A collection of web pages connected (linked) by
Hypertext clickable links.
Web Site Storage/Hosting:
After a web site is designed it must be stored on a
computer that can be accessed through the Internet
and the World-Wide Web .
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PROTOCOL:
It is a set of conventions governing the processing
and especially the data in an electronic
communications system.
TCP/IP (Transmission Control Protocol/Internet
Protocol ):
TCP/IP is a set of protocols developed to
allow cooperating computers to share
resources across a network. They provide a
few basic services that everyone needs (file
transfer, electronic mail, remote logon, etc…)
across a very large number of client and
server systems.
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URL (Uniform Resource Locator):
The URL is a "standard" way of easily
expressing the location and data type of
a resource. URLs in general take the
form "protocol://address" where protocol
is something like HTTP, FTP, telnet,
and so on, and the address is merely the
server name of a given resource or
page.
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DNS (Domain Name Services):
DNS refers to a network service that associates
host names (alphanumeric) with their equivalent
TCP/IP address. This is done by the means of a
standard look-up table.
Example:
Translation from domain names:
http://www.comsats.edu.pk into correct TCP/IP
addresses, e.g. 203.124.43.105.
Telnet :
Telnet is the way you can access someone else's
computer, assuming they have given you
permission.
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SMTP (Simple Mail Transfer Protocol):
SMTP is the standard protocol used to
exchange Internet mail between TCP/IP
hosts. “Message Handling Systems”
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Domain (s)


On the Internet, a domain is basically a registration
category identifying geographic or purpose
commonality.
There are seven top-level domains currently in use:

com - A commercial organization. The
largest domain extension currently used.
 edu - An educational establishment such as
a school or university.
 gov - A branch of the government that is
strictly reserved for that purpose.
 int - An international organization such as
the United Nations.
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Domain (s) (Cont.)




net - A network organization.
org - A non-profit organization.
mil - A branch of the military that is strictly
reserved for that purpose.
In other parts of the world the final part
of the domain name represents the
country in which the server is located
like pk for Pakistan, bb for Barbados, ca
for Canada and uk for Great Britain.
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Internet:



At its most basic level, the Internet is an utility
connecting localized computer networks (that might
exist in a lab, in a building, in a department, or on a
campus) with computer networks that extend across
a wider area, like a region or a continent.
Technically, what distinguishes the Internet is its
use of a set of protocols called TCP/IP. Two recent
adaptations of the Internet technology are the
Intranet and the Extranet.
The term 'Internet' comes out of the concept of
'internetworking'
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World-Wide Web:
The World-Wide Web (WWW) is a pair
of software applications, which allow
both distribution of and access to
information on the Internet. The web is
not the Internet but a means of
distributing
and
accessing
the
information that is on it.
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3D Map of WWW
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E-COMMERCE / E-BUSINESS:

"E-Commerce" (Electronic Commerce or
EC) is the buying and selling of goods
and services on the Internet, especially on
the World-Wide Web.

Example of E-Commerce Website:
Amazon.com
(http://www.amazon.com)
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FIRE WALL:


A firewall is a program, usually an Internet gateway
server, that protects the resources of one network
from users from other networks. Any enterprise will
want a firewall to prevent outsiders from accessing its
own private data resources.
There are a number of firewall screening methods. A
simple one is to screen requests to make sure they
come from acceptable domain names and IP
addresses. Another is to not allow Telnet access into
your network except for your own users.
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Firewall
INTERNET
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HTTP:
The Hypertext Transfer Protocol is the set
of rules for exchanging files (text, graphic
images, sound, video, and other
multimedia files) on the World Wide Web.
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HTTP (HyperText Transfer Protocol):
User request document from browser.
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1
BROWSER
Display web page.
USER
5
Send request.
Send response.
3
Open connection of web server.
2
WEB SERVER
4
Searching for the document.
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Web Server:


Stores and transmits web documents (files). It uses
the HTTP protocol to connect to other computers and
distribute information.
Example: IIS, Apache, Sun Java System Web Server
FTP (File Transfer Protocol):



FTP is the standard used to transfer files over the
Internet.
FTP allows you to copy any kind of computer file (text,
software, images, sounds, fonts, etc...) from one
computer to another via a network using the Internet.
FTP is not platform-specific, so as long as you have a
computer (DOS, Macintosh, Unix, etc.) that is
connected to the Internet, you can copy files.
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COMSATS Web Server
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ISP (Internet Service Provider):

An ISP is a company that provides individuals
and other companies access to the Internet
and other related services such as Web site
development and hosting (web site storage).

The larger ISPs have their own high-speed
leased lines so that they are less dependent
on the telecommunication providers and can
provide better service to their customers.
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ISPs and Backbone Service Providers
Click to view
animation. Click
once only.
3. Your request
goes to a network
access point
(NAP).
NATIONAL
4. Your request goes
to a national
backbone network.
1. You request a
Web page.
YOU ARE
HERE
R
E
G
I
O
N
A
L
2. Your request
goes to your ISP’s
point of presence
(POP).
5. Your request reaches
the Web site’s server
and the Web page is
sent back to you in
packets.
Java Applet:
 An applet is a small program run on the
Web, using Java, the object-oriented
programming language.
 It can be can be sent along with a Web
page to a user.
 It can perform interactive animations,
immediate calculations without having to
send a user’s request back to the server.
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XML (eXtensible Markup Language):
 XML
is a flexible way to create
information formats and shared on the
World Wide Web, intranets, and
elsewhere,
 Example, computer makers might agree
on a standard or common way to describe
the information about a computer product
(processor speed, memory size, …) and
then describe the product information
format with XML.
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XML (eXtensible Markup Language):
 Such a standard way of describing data
would enable a user to send an intelligent
agent (a program) to each computer
maker's Web site, gather data, and then
make a valid comparison.
 XML can be used by any individual or
group of individuals or companies that
wants to share information in a consistent
way.
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XML (eXtensible Markup Language):


XML is currently a formal recommendation from the
World-Wide Web Consortium (W3C) as a way to
make the Web a more versatile tool.
XML is similar to the language of today's Web pages,
HTML in that both contain markup symbols to
describe the contents of a page or file. HTML,
however, describes the content of a Web page
(mainly text and graphic images) only in terms of how
it is to be displayed and interacted with. Example: a
<P> starts a new paragraph.
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XML (eXtensible Markup Language):
 XML describes the content in terms of
what data is being described. e.g., a
<PHONENUM> could indicate that the
data that followed it was a phone number.
 This means that an XML file can be
processed purely as data by a program or
it can be stored with similar data on
another computer or, like an HTML file,
that it can be displayed.
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How XML codes look like
<note> <to>Employee</to>
<from>Supervisor</from>
<heading>Reminder</heading>
<body>Don't forget me this
weekend!</body> </note>
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History of the Internet:
•
•
•
•
The Internet grew out of many developments in
computer networking and telecommunications
research.
Early projects undertaken in early 1960’s by the
US military (known as DARPAnet).
Started with a dozen of Networked computer
systems of universities and institutions, allowing
computers to be shared.
Allowing fast communication between researchers
through Emails.
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History of the Internet (Cont.)
•
•
•
Only people in the government, military and
academic had access to the network.
In 1991, the National Science Foundation (NFS)
gradually started backing off from its subsidy of the
backbone network, then allowed commercial access
to the internet.
With commercial access to the Internet, businesses
and all kinds of agencies began to use the Internet to
communicate, exchange data and distribute
information;
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History of the Internet (Cont.)
•
A host of businesses called Internet
Service Providers (ISPs) sprang up. ISPs
provide dialup access to the Internet; an
individual or a business opens an
account with the ISP, dials into the ISP's
computer and via the ISP's computer
connects to the Internet.
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History of the Internet (Cont.)
•
Internet traffic grew,



Many businesses spent heavily to improve
the internet, therefore to better service their
customers.
Big competition among communication
carriers, hardware and software suppliers.
As a result, Internet’s bandwidth climbed
high, & cost went down!
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The Internet’s History

Significant events in the history of the Internet.
J.C.R.
Lickliter
conceives
of the idea
of a
“galactic
network”.
Click on the dates for more information.
Ray Tomlinson
invents e-mail.
1962
The World Wide
Web is
developed.
1972
1969
ARPANET goes
online, connecting
four computers.
1989
1983
Internet
protocols
begin.
The first
graphical
Web
browser is
developed.
1994
1995
Barriers to
commercial
activity are lifted.
The Future of the Internet
Key changes in the Internet need to take
place to handle the growing number of
users and the speed of the connections.
 Future changes include:

 More bandwidth
 Internet 2 (I2) is being developed and tested to
establish gigabits per second Points of Presence
(gigaPOP).
History of the World-Wide Web
•
WWW allows computer users to locate and
display multimedia-based documents,
•
Introduced in 1990 by Tim Berners-Lee of
CERN (Geneva).
•
Today’s Internet mixes computing and
communications technologies.
•
It makes our work easier.
•
It is changing the nature of the way business is
done.
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History of the World-Wide Web (Cont.)
•
•
•
It
makes
information
instantly
and
conveniently available to anyone with a
connection
Communities can stay in touch with one
another.
Researchers can learn of scientific and
academic breakthroughs worldwide.
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The Internet and Web: What’s the
Difference?
The Internet is the physical connection of
millions of networks.
 The Web uses the Internet for its
existence.
 The Web consists of hypertext embedded
on Web pages that are hosted on Web
sites.

2. Internet Applications
•
Internet Protocols
HTTP (HyperText Transfer Protocol):
which are the basis for information
exchange on the Internet), HTTP is an
application protocol.
HTTPs (“s” stands for security):
is the same way as HTTP but used
securely.
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FTP (File Transfer Protocol)
Telnet
Other alternative in the Market: Terminal
Services, PC Anywhere
•


Email (Electronic Mail)
E-mail is the exchange of computerstored messages by telecommunication.
you can send messages (text, graphic
images and sound files) as attachments.
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•



Email (Electronic Mail) (Cont.)
E-mail was one of the first uses of the
Internet. Probably it is still the most
widely used internet application.
A large percentage of the total traffic
over the Internet is e-mail.
It uses Simple Mail Transfer Protocol or
SMTP.
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Search Engines
Web sites that sort through by keywords
and categories:
•

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
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
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
Google (www.google.com)
Yahoo (www.yahoo.com)
Lycos (www.lycos.com)
Altavista (www.altavista.com)
Store information in databases.
Returns list of sites as hyperlinks.
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Search Engines (Cont.)
Meta-search engines:
•





No Database maintenance.
Combine results from multiple search
engines.
Microsoft MSN: www.msn.com
IE5.5 has a built-in meta-search engine that
is accessed by clicking the search button
on the toolbar.
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3. Internet Architecture & Topologies
•
Internet Service Providers (ISPs)
 To get to the internet we need to pay
“people at access points”, are the ISPs

Because they have high speed
connections to the internet, and
dedicated hardware.
 They sell their services back to users like
Email, web storage, slower internet
access dialup or dedicated line.
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•

Internet Service Providers (Cont.)
Commercial ones out there:
www.aol.com,
join.msn.com,
www.NetZero.com, …
www.Guno.com, …
…..
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•
Domains
Internet registration category identification for
geographic and Common purposes, e.g. .com,
.com.my, others like .ac.uk, .co.uk
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Intranets

What is an Intranet?
Intranets are private corporate information and
collaboration systems that use Internet software and
standards.
Why an Intranet
The Intranet can increase market share, profitability,
and efficiency.

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•
Why Intranet (Cont.)

Ideal place for publishing continuously updated
Corporate information.
Powerful, not expensive communications alternative
that can provide information anywhere at anytime.
Intranet technology can be used across wide area
networks.
Web server software inter-operates well.
Web servers do not need large capital expenditures
in hardware.




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•
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How can Intranet help a company?
Intranets can be relatively easy to install, and
inexpensive to administer. Also eliminate Printing,
and out-of-date information
Procedures Manuals
Company Practices
Company phone book
Catalog and Inventory lists
Employee benefits information (Health-care benefits)
Bulletin boards
Job Postings
In-house newsletters or publications
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•
How can Intranet help a company? (Cont.)

Training
Presentations
Order Processing
Expense Report
Sales Force Automation ( Offsite employees
conducting sales, marketing, … can access all the
companies information remotely easily and in a cost
effective way)
Help-desk and technical support
Company suppliers information (What each supplier is
quoting at each specific location)






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•
How can Intranet help a company?
(Cont.)



Access search and sort database records
dynamically by converting databases to
HTML on the fly, in SQL or other formats.
Sort through thousands of documents and
quickly retrieve the information you need
with the proper search engine.
Video Conferencing
Putting such applications on an Intranet
can serve a large group of users at a
substantially low cost.
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EXAMPLE OF CIIT INTRANET
•
Extranets
What is an Extranet?

An Extranet is a collaborative network that uses
Internet technology to link businesses with their
suppliers, customers or other businesses that share
common goals.

An Extranet can be viewed either as part of a
company's Intranet that is made accessible to other
companies or as a collaborative Internet connection
with other companies.

The shared information can be accessible only to the
collaborating parties or can be publicly accessible.
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Extranet applications (some examples):


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

Private newsgroups that cooperating companies use
to share valuable experiences and ideas.
Training programs or other educational material that
companies develop and share.
Shared product catalogs accessible only to
wholesalers or those "in the trade".
Project management and control for companies that
are part of a common work project.
An Extranet usually requires a degree of security and
privacy from competitors.
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Extranet
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Summary
Internet has evolved over the time
 Future challenges of internet includes
transferring high volume of data.
 World Wide Web (www or w3) is a system
of interlinked hypertext documents that are
accessed via the Internet.
 With a web browser, one can view web
pages that may contain text, images,
videos, and other multimedia and navigate
between them via hyperlinks.
