World Wide Web | Working of WWW | WWW Architecture

Introduction of World Wide Web (WWW)

World wide web is collection of millions of files stored on thousands of servers all over the world. These files represent documents, pictures, video, sounds, programs, interactive environments.

A webpage is an HTML document that is stored on a web server. A website is a collection of web pages belonging to a particular organization. URL of these pages share a common prefix, which is the address of the home page. Home page is the front door of a website. For example, any organization website is “www.facebook.com”, the URL to which they refer is the URL of the site’s home page. The homepage introduces the rest of the web site and provides links that leads to other pages on the site.

Web Browsers

A web browser is a software(application). Web browser is used to communicate with web servers on the internet, which enables it to download and display the Webpages. IE, Chrome, Firefox are most popular browser in market. Browser interact with web as well as computer operating system and with other programs.

IE is the default browser in newly installed OS. Some of the basic elements of browser are- Menu bar, Tool bar, Address or location window, Viewing window, Status bar. The purpose of web browser is to display web pages, which may either arrive over the Internet. Web browser can be used to view files of any common web format that are stored on the user system. Web clients, called web browsers, interpret Hyper Text Markup Language documents delivered from the web server.

 

Web Servers

The server provides the copy of the page along with the additional information. The additional information a www server returns tell the browser two important things: 1. It describes how to display the information 2. It gives a URL for each selectable item on the page. Each URL uniquely identifies a page of information by giving the name of a remote computer, how the URL encodes the information. It is multimedia because the information it holds can be in the form of text, graphics, sound and video. The information being retrieved can be information located anywhere in the world. The normal way to provide information on the world wide web is by writing documents in HTML.

Working of WWW

Figure: Working of WWW

Step -1:

User enter an URL in Browser. Ex., www.facebook.com. The browser asks DNS for the IP address of URL. (Client Side)

Step-2:

DNS replies with IP Address ex.,172.16.16.1 (DNS Server)

Step-3:

The browser makes a TCP connection to port 443 on 172.16.16.1 and sends a request to server for Webpage. (Client Side)

Accept a TCP connection from a client browser. Get the name of the file required. (Server Side)

Step-4:

Search the requested file from stored files. Get the requested file from directory. Return the file to the client. Release the TCP connection. (Server Side)

Step-5:

Sends a request to server for Webpage. Client receive the requested file. TCP connection is released. The browser fetched and displays all images in this file. (Client Side)

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