Chapter Six · Part 2: The Network

The Internet

In the last chapter your devices reached as far as your router. This chapter follows what happens past it — how millions of separate networks join into the one thing we call the internet, how a request to example.com crosses the world in under a second, and why all of it runs on very physical cables, some of them lying on the ocean floor.

3 topics

So far, opening example.com has only taken us as far as your home network: your devices talk to your router, and the router faces outward. This chapter is about that outward-facing part — the enormous thing on the other side of your router that the word "internet" actually names.

The surprise is that the internet is not one machine or one cable you could point at. It is millions of separate networks — homes, companies, data centers — that agree to connect and pass each other's data along. These three topics build that picture: first what the internet is made of, then how your request travels across it to reach a faraway computer, and finally what the whole thing is physically built from.

The internet from the three angles this chapter covers

Many networks

The internet is countless separate networks — homes, offices, data centers — that agree to connect, with no single owner.

One journey

Your request to a site hops from network to network across the world, and the answer returns the same way, in under a second.

All physical

It only feels wireless for the first few meters — past your router it is cables, including ones that cross entire oceans.