Every email, video call, and page you've ever opened crossed a network of cables, radio waves, and silicon — hopping between machines that don't know each other but agree on the same rules. This lesson is an interactive walk through how that actually works.
A computer network is simply two or more devices linked together so they can exchange data and share resources — files, printers, an internet connection, even processing power. The devices are called nodes; the links between them can be copper cable, fibre, or radio waves.
One printer or one internet line can serve every device on the network instead of buying one per machine.
Email, chat, and video calls are only possible because devices can pass messages to each other in real time.
With more than one path between two points, traffic can reroute automatically if a cable or server fails.
New devices can join an existing network without rebuilding it — that's how home Wi-Fi and the Internet both grow.
The same idea — devices exchanging data — looks very different depending on how far it has to reach. Networks are usually grouped by physical scale.
The smallest scale — devices belonging to one person, usually within arm's reach, connected wirelessly over short range.
Devices within one building or campus, usually owned and managed by a single organisation — an office, school lab, or home.
Several LANs linked across a city — connecting campuses, branch offices, or a cable provider's local infrastructure.
Networks spanning countries or continents, linking LANs and MANs together — the Internet is the largest WAN of all.
Topology is the shape of the connections — which device is wired to which. The shape decides how data travels, how easy the network is to grow, and what happens when one link fails.
Behind every connection sits physical hardware. Click a card to see what each device actually does.
Beyond wiring, networks also follow a logical model for how devices request and provide data.
Clients request → server responds. Example: opening a website, checking email.
Every peer can act as both client and server. Example: file-sharing networks, some blockchain networks.
Real-world networks split the job of "send this data" into seven layers, each with one responsibility, agreed on by every device on the Internet. Click a layer to read about it, or watch data make the full trip.
Five quick questions covering everything above.