Explanation of the Internet and the WWW: How Does it Work?

This resource is designed specifically for Unit 6 of the Edexcel BTEC qualification, 'Business Online'.

Aim

The aim of this section is to generate an understanding of how the Internet works and the difference between the Internet and the Web.

What is the Internet?

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Very simply, the Internet is worldwide collection of computers all connected together to form a huge network. These computers communicate with each other through a set of common software standards known as protocols. These protocols allow the sending and receiving of emails; viewing of Web pages; the transfer of files between one computer and another; instant messaging with other users, etc.

In order for these protocols to work there must be a way of identifying each machine connected to the Internet. Each machine connected to the Internet has an address known as an Internet Protocol address (IP address). The IP address takes the form of a series of four numbers separated by dots, for example: 123.45.67.890

With this in mind, what happens when you type a Web page address into your Web browser?

1. A user types in the address http://www.bized.co.uk into a Web browser (for example: Microsoft Internet Explorer or Mozilla).
2. The Web browser sends this information to a program called a name server. Usually this program is running on a computer operated by the people who provide you with an Internet connection (your Internet Service Provider or ISP). Part of the sign up process with an ISP involves 'telling' your computer the location of the name server - usually the setup software from the ISP does this for you so you are rarely involved with the setup.
3. On receiving the Web address the name server may communicate with other name servers running on computers all over the world. The name servers associate the Web address with an IP address.
4. This IP address is then returned to the Web browser.
5. On receiving the IP address the Web browser now knows the precise address of the computer it needs to connect to in order to receive the appropriate Web page.

In the above description the Web address is an example of a hostname. Name servers turn/resolve these hostnames into IP addresses refering to computers on the Internet. The network of programs and information sources that allow the resolution of hostnames is known as the Domain Name System (DNS). Although the example referred to a Web address the process is the same for establishing where to deliver email or setting up file transfers between different computers.

What is the World Wide Web?

The World Wide Web (WWW, W3 or just Web) was invented by Sir Tim Berners-Lee and is an information system that allows users to view documents (called Web pages) using a piece of software called a Web browser. These Web pages are located on computers all over the world (connected via the Internet); these computers all run software known as a Web server (the most commonly used is called Apache) which waits for requests for Web pages (as outlined above), processes the request and sends the requested page back to the Web browser. These Web pages contain links to other related documents. It is these links between documents that give the Web its name. The links work because every document on the Web is referred to via a Universal Resource Locator or URL (although the more modern/correct practice is to use the phrase: Uniform Resource Identifier or URI instead, the reasoning behind this is out of the scope of this BTEC resource). The URL for this page is:

http://www.bized.co.uk/educators/16-19/business/marketing/lesson/internet1.htm

The specific parts of this URL are:

http:// - stands for HyperText Transfer Protocol. You'll remember that the Internet is made up of computers communicating with each other through standard protocols. HyperText is one such protocol and is the one used to transfer Web pages.

www - the name of the computer/server on which the files you are requesting reside.

bized.co.uk - the domain/host name. The .ac.uk part means this domain name is for an academic organisation in the UK. Other examples include .com = intended for commercial organisation (but not exclusively so), .gov.uk = UK government, etc.

/educators/16-19/business/marketing/lesson/ - directory/folder path on the Web server.

internet1.htm - the filename for this page.

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