Home-working should have overloaded the internet. Why didn’t it?

The internet’s surge protectors have just survived a major convulsion. Hundreds of millions of people have suddenly found themselves working — and movie-watching, game-playing and video-calling — from home throughout the day. The result, according to Matthew Prince, head of internet infrastructure company Cloudflare, has been a spike in demand that would have brought any other public utility to its knees. His company’s network has seen demand rise more than 50 per cent — the kind of spike that “would be a disaster” in a sewer system or electric grid, he said. That online traffic has not ground to a halt under the weight of so much screen time owes much to a collection of specialist networks overlaid on top of the internet to help with the heavy lifting. Known as content delivery networks, they specialise in serving up movies, web pages or any other form of internet content in the most efficient way possible. Key to the way they work is to store copies of the most popular online content on servers around the world, putting it closer to users. This technique, called caching, means that when anyone tries to stream a song or check a website, the digital bits can usually be shipped from a nearby computer, rather than from half a world away. That reduces the traffic travelling over the “core” network, easing pressure on the internet’s trunk routes and reducing the lag before content is delivered — something known as latency.