LAN (Local Area Network): covers a small geographic area — single building, school, office. Infrastructure typically owned and managed by the organisation. High speed.
WAN (Wide Area Network): covers large geographic areas — cities, countries, globally. Uses public or leased infrastructure (telephone lines, fibre, satellites). The internet is the largest WAN.
PAN (Personal Area Network): very small range — Bluetooth devices, smartwatches. Range: typically 10 metres
Client-Server vs Peer-to-Peer
Network Models
Client-server: a central server provides resources (files, login, email) to client devices. Centralised control — easier to manage, back up, and secure. Used in schools, businesses.
Peer-to-peer (P2P): every device acts as both client and server. No central server. Each device shares its own resources. Examples: home networks, BitTorrent file sharing.
Client-server: easier admin but expensive; P2P: cheap but harder to manage and less secure
Network Hardware
Key Devices in a Network
Router: connects different networks and routes packets between them; connects LAN to WAN/internet
Switch: connects devices within a LAN; sends data only to the intended device (uses MAC address)
Hub: like a switch but broadcasts to all devices — less efficient; largely obsolete
NIC (Network Interface Card): hardware inside a device that allows it to connect to a network
WAP (Wireless Access Point): allows wireless devices to connect to a wired network
Exam Practice
Have a go at this question
Edexcel-style question
Describe one difference between a LAN and a WAN.
2 marks
A LAN covers a small geographic area (e.g. a school building) [1], whereas a WAN spans a large geographic area such as a country or the whole globe [1].
Key Takeaways
What to Remember
LAN: small area, owned infrastructure; WAN: large area, uses public/leased lines
Client-server: centralised, managed; P2P: decentralised, cheaper, less secure
Router: between networks; Switch: within LAN; WAP: wireless connection
PAN: personal range (Bluetooth); LAN: building; WAN: global