What is World Wide Web?

The World Wide Web is a huge repository of information that can be accessed through linked documents spread over thousands of machines spanning the Internet. It is logically an interconnected web of documents called Web Pages.

What is the technology that drives the WWW?

• A Client-server system.
• Web pages can be viewed using a Web browser.
• A Web browser is a universal client.
• Web browsers are available for most platforms, thus making the access to the WWW platform independent.
• The WWW operates in a stateless environment.
• The Web Server and the Web Browser interact using HTTP and port no. 80

What is HTTP?

HTTP, short for hyper text transfer protocol, is the front-end protocol used by the World Wide Web. HTTP specifies how messages are formatted and transmitted, and what actions Web Servers and Browsers should take in response to various commands. For example: When you enter a URL in your browser, this actually sends an HTTP command to the Web Server directing it to fetch and transmit the requested Web page.

What is a URL?

URL, short for Uniform Resource Locator, is a means of specifying the location of a web page that we wish to browse. URL also helps in specifying different protocols for different services that we want to access.

A URL has three components:

• the access protocol.
• the Domain Name of the machine on which the page or information resides.
• local path name to identify the file.

Example URLs:

Intranet

An important constituent of the internet are the numerous intranets that form a part of the internet. Intranets generally consist of internal corporate web servers made available to employees across a local network. Through links to corporate databases, file servers, and document archives, web servers bring diverse kinds of information to employees via a single front end - the web browser. Web browsers are available for all platforms - this makes the information access platform independent.

Intranets are relatively inexpensive to install and administer. Web browsers are available free. Web servers come pre-packaged with most operating systems. A large number of useful application programs and tools have been developed for the Internet which can be used on the intranet as well - the use of these technologies is not restricted to the Internet alone. Most of these applications are either free or quite inexpensive.

Some of the powerful technologies that have resulted are:

• Web Browsers such as IE, Firefox.
• Web Servers such as Apache, IIS, Tomcat.
• HTML & HTTP
• Javascript, Java, CGI, ASP, JSP, PHP

These technologies have made it easy for diverse internet/intranet sites to share all kinds of information.

All of these Internet technologies can be replicated in a corporate network, thereby enabling the organization to create a powerful corporate information system, called the Intranet.

Intranet implementation can help organizations to:

• Speed up the internal communication.
• Reduce paper.
• Display information of common interest to employees.
• Collect feedback and suggestions from employees

What is Internet?

It is not another category of network. It is a Network of Networks. The Internet is a collection of Packet-switched networks interconnected by routers and gateways, and using the common language TCP/IP � thus functioning logically as a single, large, virtual network. The glue that binds the Internet is TCP/IP. It connects various networks in a seamless manner.

History & Evolution of Internet

The internet evolved during the cold war days when US and USSR were in constant race for technological supremacy. The US Department of Defense�s ARPA started developing a network which could withstand war situations. Packet-switching and TCP/IP were innovated by ARPA in the early 1980�s. Soon, as the usage became easier and acceptable, contractors of the US government were also included in the network. This network was called the ARPAnet.

In 1983 ARPANET was split into � (a) Milnet (Military network) for defense establishments, and (b) ARPAnet for the scientific and other user community.