How the internet works: The intriguing science of how your device is able to load this sentence right here

The internet is a collaboration between computers all over the world (although some countries restrict access). When you type in a URL (uniform resource locator, or web address) such as https://www.sciencefocus.com, your computer first has to figure out which computer to talk to…

1. Every computer has a unique IP (internet protocol) address, consisting of sets of numbers separated by dots. To find the right IP address from the URL, your computer first talks to DNS (domain name system) servers, which pass the request up a hierarchy until each set of numbers has been resolved to get the IP address.

2. Your computer now starts to establish a connection to that address, a process that involves a chain of computers all passing data between your computer and the server that hosts the website you want. The chain is optimised to minimise the number of steps and potential errors, giving you the fastest, most reliable speed.

3. Once the connection is made, your computer can talk to the server, which will provide the data you want – a funny cat video, for example. They both speak the language of the internet: TCP/IP (transmission control protocol/internet protocol). Little packets of data are sent in this language that’s been specially designed to check for errors and ensure all the data arrives correctly.

Your computer also knows that the server follows the HTTPS (hypertext transfer protocol secure) protocol – the first part of the URL – so when it puts the packets together and sees an HTML (hypertext markup language) web page, it knows how to display the content.

4. Today’s web pages are often very complicated. Their HTML code may specify content stored on other computers, each with their own domain names, so as your computer displays the content, it has to keep asking the DNS servers ‘where is this?’ and quickly establishing new connections to other computers.

Sometimes your computer asks more complicated questions, such as: ‘what is being said in this audio recording taken from my user’s Alexa device?’ The servers then have to perform complex artificial intelligence processing and reply with the result.

5. All of this communication happens dynamically across the world, with servers providing data through whatever connections are available, making the internet amazingly robust.

Read more:

• What would happen if the internet went down?
• How do machine learning GANs work?
• Web inventor Tim Berners-Lee thinks his creation is out of control. Here's his plan to save it

Asked by: Blair Benson, via email

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