4.1.2 LAN and WAN
Types of Network
Networks are classified by their geographical scale. The two types you need to know are LAN and WAN.
A LAN (Local Area Network) is a network that connects devices within a small, geographically limited area — typically a single building or campus.
- Scale: single building, home, school, office, hospital site
- Ownership: the hardware (cables, switches, access points) is usually owned by the organisation using it
- Connection types: wired (Ethernet cables) or wireless (Wi-Fi)
- Speed: typically very fast — 100 Mbps to 10 Gbps on modern wired LANs
- Examples: a school network linking all classrooms; home Wi-Fi connecting phones, laptops and smart devices
A WAN (Wide Area Network) is a network that connects devices over a large geographical area — potentially spanning cities, countries or continents.
- Scale: cities, countries, worldwide
- Ownership: the infrastructure (long-distance cables, fibre, satellite links) is typically owned and leased from telecommunications companies
- Connection types: fibre optic cables, satellite links, telephone lines
- Speed: generally slower and more variable than LANs due to longer distances and shared public infrastructure
- Examples: the internet (the largest WAN in existence); a multinational company connecting its offices in London, New York and Tokyo
Comparison
| Property | LAN | WAN |
|---|---|---|
| Geographical scale | Single building / campus | Cities, countries, worldwide |
| Typical ownership | Organisation owns the hardware | Leased from telecoms providers |
| Typical speed | High (100 Mbps–10 Gbps) | Lower and more variable |
| Infrastructure cost | Lower (cable within building) | High (long-distance infrastructure) |
| Example | School network, home Wi-Fi | The internet, corporate WAN |
The internet is the world's largest WAN, connecting billions of devices globally via a vast infrastructure of undersea cables, fibre optic links, satellites and exchange points.
Key Takeaways
- LAN: local area — single building/campus; organisation-owned hardware; fast; wired or wireless.
- WAN: wide area — large geography; leased infrastructure; generally slower; includes the internet.
- The internet is the world's largest WAN.
- The key distinguishing factors are: geographical scale, who owns the infrastructure, and typical connection speed.