Every network needs a way to physically move the ones and zeros between devices. You have two choices: send them down a wire, or fling them through the air as radio waves. Each has real strengths and real weaknesses, and choosing between Ethernet and Wi-Fi is one of the most practical decisions in networking.
Wired networks: Ethernet
Ethernet connects devices with physical cables (usually twisted-pair copper) into a switch or router. Signals stay inside the wire, so wired links are typically faster, more reliable and more secure than wireless — nothing to interfere with them and no signal leaking into the street. The catch is that you can't move around, and running cables through a building is expensive and disruptive. It's the difference between a train on fixed rails (fast and dependable, but you go where the track goes) and walking (free to roam, but slower).
Wireless networks: Wi-Fi
Wi-Fi uses radio waves broadcast by a Wireless Access Point (WAP), often built into the router. It's convenient and lets devices roam, but the signal weakens with distance and through walls, can suffer interference, and — crucially — travels through open air where anyone in range could try to intercept it. That's why wireless data must be encrypted.
| Feature | Wired (Ethernet) | Wireless (Wi-Fi) |
|---|---|---|
| Speed | Usually higher | Lower, varies with distance |
| Reliability | Very reliable | Can suffer interference |
| Security | Harder to intercept | Signal in open air — must encrypt |
| Convenience | Fixed location | Move around freely |
Encryption and hardware
Because Wi-Fi signals leak everywhere, they are protected by encryption — the current standard is WPA2 (and WPA3). Encryption scrambles the data with a key so that even if someone captures the radio signal, they see only meaningless noise without the password. Key hardware includes the NIC (Network Interface Card) that gives each device an address and connects it to the network, the switch that directs traffic within a LAN, the router that joins the LAN to the internet, and the WAP that provides the wireless signal.
Tip: On public Wi-Fi you don't control, avoid logging into banking or email unless the site itself uses HTTPS — the site's own encryption protects you even when the network doesn't.