What is a Network?
A network is a system where two or more devices are connected so they can exchange data. Your phone, your laptop, even your smart bulb — every one of them is a member of at least one network right now.
01You already use one every day
- When you send a WhatsApp message, it travels through your home Wi-Fi, then your carrier's network, then on to the servers
- While you watch YouTube, hundreds of data packets stream into your device every second
- In an online game, your move reaches a player on another continent in milliseconds
Throughout this curriculum we'll open up what happens backstage, step by step: how data gets packaged, how addresses work, and how packets find their way.
02How is data transmitted?
The best analogy is still the postal system:
- You write a letter → data
- You put it in an envelope → packaging
- You write the address on it → IP address
- The post office routes it through a sorting hub → router
- It's delivered to the recipient's door → destination device
One important difference: a network never sends a long letter in a single envelope. Data is split into small pieces called packets; each piece travels on its own and everything is reassembled at the destination.
03Four concepts to meet
| Concept | What it does |
|---|---|
| Packet | A small, addressed piece of data |
| IP address | A device's address on the network |
| Router | The device that steers packets the right way |
| Protocol | The communication rules both sides agree on |
These four ideas underpin every lesson ahead. Whenever a new term trips you up, the glossary has your back:
Sandbox · ReferenceNetwork GlossaryPlain-language definitions with tiny examples for every networking term you'll meet.Open tool04Summary
- Network = devices connected to exchange data
- Data travels as packets; every packet carries its own address
- Routers steer the packets, protocols set the rules