Introduction to Internet and World Wide WebLecture 31

By

Prof. Dr. Sajjad Mohsin

Today’s Outline We will discuss today

Basic Networking Interfaces InternetWorld Wide WebApplications 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 & DefinitionsWeb 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

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INTERNET

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):

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USER

WEB SERVER

BROWSER

User request document from browser.

Searching for the document.

Open connection of web server.

Send request. Send response.

Display web page.

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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REGIONAL

LOCAL

1. You request a Web page.

2. Your request goes to your ISP’s point of presence (POP).

3. Your request goes to a network access point (NAP).

4. Your request goes to a national backbone network.

5. Your request reaches the Web site’s server and the Web page is sent back to you in packets.

YOU ARE HERE

NATIONALClick to view animation. Click once only.

ISPs and Backbone Service Providers

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 thisweekend!</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.

1962

1969

1972

1983

1989 1994

1995

J.C.R. Lickliter conceives of the idea of a “galactic network”.

Ray Tomlinson invents e-mail.

The World Wide Web is developed.

The first graphical Web browser is developed.

ARPANET goes online, connecting four computers.

Internet protocols begin.

Barriers to commercial activity are lifted.

Click on the dates for more information.

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 computer-

stored 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: 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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• DomainsInternet registration category identification for geographic and Common purposes, e.g. .com, .com.my, others like .ac.uk, .co.uk

• Intranets What is an Intranet?

Intranets are private corporate information and collaboration systems that use Internet software and standards.

Why an IntranetThe 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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• 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 ConferencingPutting 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

• ExtranetsWhat 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): 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.