Module 01 · Section 1.3.1
LAN vs WAN
INTRODUCTION
Computer networks are classified primarily by their geographical scale. There are two core types you must know for J277: the LAN and the WAN. Click Next Step to begin the walkthrough.
STEP 1 · LOCAL AREA NETWORK
A LAN (Local Area Network) covers a small geographical area — typically a single building, school site, or office floor. The organisation that uses the LAN owns all the hardware and infrastructure, including cables, switches, and routers.
STEP 2 · WIDE AREA NETWORK
A WAN (Wide Area Network) covers a large geographical area — spanning cities, countries, or globally. It connects multiple LANs together and relies on external, third-party telecommunications infrastructure such as broadband cables, satellites, and leased lines owned by Internet Service Providers (ISPs).
STEP 3 · SIDE-BY-SIDE COMPARISON
The diagram now shows both networks. Note the key distinction: the ISP in the middle represents the third-party infrastructure that belongs to neither organisation — this is the fundamental difference from a LAN.
| Feature | LAN | WAN |
|---|---|---|
| Area Covered | Single building / site | Country / global |
| Infrastructure | Organisation-owned | Third-party (ISP) |
| Speed | Generally faster | Generally slower |
| Cost to set up | Lower | Higher |
| Example | School network | The Internet |
STEP 4 · EXAMINER WARNINGS
Two critical traps from the J277 mark scheme must be avoided:
Examiner's Eye: THE WAN TRAP
If asked to define a WAN, never just write "Wide Area Network". You must explicitly state it covers a large geographical area AND that it uses third-party / external infrastructure. Both points are required to secure full marks.
Examiner's Eye: LAN DEFINITION TRAP
Never write "one building" as the only definition of a LAN — this is too restrictive. The correct phrase is "small geographical area". Examiners accept a school site (multiple buildings) as a LAN.
Step 0 of 4
LAN — Local Site
Organisation-owned hardware
Switch
PC 1
PC 2
Printer
Remote LAN
Third-party infrastructure (ISP)
Switch
Server
PC
ISP
Router
3rd-party
infrastructure
infrastructure
Viewing: LAN only
Key Points
LAN = small area, owned infra
WAN = large area, ISP/3rd-party
Internet = the world's largest WAN