How the internet works

You don’t need to be a mechanic to drive a car but it doesn’t hurt to know a bit about some of the basic principles. It’s much the same with the internet. There’s so much jargon, so many buzzwords and such complexity that it’s tempting to give up. That’s where our Back to Basics guide comes in – we’ll explain how the internet is set up, where your PC fits in, how web browsing works and what happens when you send an email to someone. We’ll also share some handy practical tips that lift the lid on the way the internet works.

A worldwide network
The internet is a worldwide network of computers (including yours, your neighbour’s, Computeractive’s, Google’s and so on). They talk to each other using a shared ‘language’ of standards that define both the physical connections and the way they’re implemented. Though originally invented in the 1960s as military and academic networks linked up, the modern internet can be traced back around 20 years. A research scientist proposed a way of presenting pages of text joined together with hyperlinks. This would become the world wide web as we know it today.

Physical connections
The billions of computers that make up the internet are mainly connected together with cables – everything from the old telephone wire coming out of your house to a fancy fibre-optic cable that can throw data around at light speed.

For most people, connecting to the internet means using an Asymmetric Digital Subscriber Line (ADSL). Such connections are more commonly referred to as ‘broadband’. The PC connects to a broadband router, which in turn is plugged into a micro-filter connected to a standard phone socket. This ‘splits’ the line so you can talk on the phone while still using the internet.

From here the line goes to the local telephone exchange before heading off to servers owned by your internet service provider (ISP) then out onto the rest of the internet. Fibre-optic cables span continents and oceans and can transmit trillions of bits of information per second. Satellites are also part of the mix.

Most of the time, a home PC is a sort of window shopper, wandering the internet, looking at pages ‘served’ by powerful computers called servers. When visiting sites like www.computeractive.co.uk, our server computer sends the information across the internet to your PC’s web browser when requested.

Looking at web pages
So, when www.computeractive.co.uk is typed into a web browser, how does it know how to find, request and then display that website, rather than any of the billions of others? The answer is an internet protocol address (IP address). Every computer connected to the internet has a unique IP address. They are really numbers and, as every one is different (a bit like phone numbers), it means any computer can find any other computer.

The IP address of the Computeractive website, for example, is 62.140.213.251. Of course, that’s not easy to remember so websites use something called the Domain Name System (or DNS) to ‘translate’ people-friendly addresses like www.bbc.co.uk into computer-friendly ones such as 212.58.244.142. However, it’s still possible to type IP addresses straight into a web browser’s Address or Location bar – type 212.58.244.142 and you’ll reach the BBC website.