Explaining the Internet

Posted July 11th, 2011 by Jason N

Billions of people around the world are using the Internet, and whether they know it or not, there are lots of things happening under the hood letting them browse the web, play online games, stream video, etc. This article hopes to give a little insight into how the Internet actually works.

Firstly, the Internet is different from the World Wide Web, and it is a common misconception to think that websites and the like ‘are’ the Internet. The Internet is a system of networks that communicate using the TCP/IP standards, allowing for data to be sent and received from around the world. Let’s first look into how the average computer connects to the Internet.

Computers connect to the Internet from their local network, to the global network that is often known as the ‘cloud’. And according to the TCP/IP protocols, your network is given what’s called an IP address. This is what’s used to identify your network and set it apart from the millions of others connected to the Internet. This is called the external IP address, and yours happens to be 136.243.106.139.

As I said, it’s your ‘network’ that connects to the internet, which means your network gets a single IP address. But what if you have several computers in your network? Well the individual devices in the network get an IP address too, which is called an internal IP address, and this is administered by the router, network switch, or even network admin of your home, company or other organisation.

But how do we ‘surf the net’? The answer is the Hypertext Transfer Protocol. HTTP is yet another protocol used on the Internet, and it allows you to connect to websites and transfer files and web pages. When you connect to a website, you send a ‘request’ to the websites server. This request asks for a certain web page, image, or other piece of information, and sends some other details like cookies, the browser name, etc, that may be needed by the server. The server then sends a ‘response’ back to your computer, which tells the browser what to display, or where to go. This response ‘should’ be what you asked for, which is usually the HTML of the web page you’re after. But if there’s an error, it may send a 404 not found status code, or send a redirect code, or forbid access to what you’re trying to view.

HTTP is one of many protocols used on the Internet. FTP, the File Transfer Protocol is optimised for file systems and transferring files over the Internet. There are others, such as streaming protocols like RTSP, or RTP.

This article has only scratched the surface of the net, so look out for part 2, which will cover the more complex principles of the Internet.