How Ethernet Cables Negotiate Their Speed

Your internet cables perform a secret handshake every time you plug them in. Without you noticing, devices instantly test and agree on the fastest possible connection speed to ensure they never lose data.

This silent conversation is called autonegotiation and happens in the blink of an eye. Two devices exchange their technical capabilities to find a middle ground that balances speed and stability. If one device is older or slower, the network automatically downgrades to a compatible speed instead of failing completely. It is the reason you can mix and match different hardware generations without manual configuration.