How a message crosses the internet
There is no route planned in advance and no single machine in charge. A packet is passed from stranger to stranger until it arrives, or does not.
How Computers Work · Part 6
Subject
Networking
How separate machines are persuaded to behave like one network.
Turns up alongside
Part of a thread
From a switch to the internet
Each layer hides the one below it until a message can cross the world.