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This lesson introduces the two main types of computer networks — LAN (Local Area Network) and WAN (Wide Area Network) — as required by OCR J277 Section 1.3.1. Understanding the differences between these network types is essential for your GCSE exam.
A computer network is two or more devices connected together so they can communicate and share resources (such as files, printers, and internet connections).
Networks can be as small as two computers connected in a home, or as large as millions of devices connected across the world (the internet).
A LAN is a network that covers a small geographical area, such as a single building, a school, or an office.
| Feature | Detail |
|---|---|
| Geographical area | Small — a single room, building, or campus |
| Ownership | Owned and managed by one organisation or individual |
| Hardware | Switches, routers, access points, cables |
| Speed | High — typically 100 Mbps to 10 Gbps |
| Cost | Lower setup cost (shorter cables, fewer devices) |
| Examples | School network, home network, office network |
A typical school LAN might include:
LANs use physical cables (typically Ethernet cables — Cat5e or Cat6) and/or wireless connections (WiFi) to connect devices. The key networking device in a LAN is the switch, which directs data to the correct device.
A WAN is a network that covers a large geographical area, connecting LANs that may be in different cities, countries, or continents.
| Feature | Detail |
|---|---|
| Geographical area | Large — across cities, countries, or the entire world |
| Ownership | Typically relies on infrastructure owned by third-party telecommunications companies |
| Hardware | Routers, modems, leased lines, fibre optic cables, satellites |
| Speed | Variable — depends on the connection type and distance |
| Cost | Higher — requires leased lines or subscription to ISP services |
| Examples | The internet (the largest WAN), a company network spanning multiple offices |
The internet is the largest and most well-known WAN. It connects billions of devices worldwide using a combination of:
A WAN is typically not owned by a single organisation. Instead, it uses infrastructure provided by Internet Service Providers (ISPs) and telecommunications companies.
| Feature | LAN | WAN |
|---|---|---|
| Area | Small (single building/site) | Large (cities/countries/global) |
| Ownership | Owned by one organisation | Uses third-party infrastructure |
| Speed | High (100 Mbps - 10 Gbps) | Variable (often slower) |
| Cost | Lower setup cost | Higher (leased lines, ISP fees) |
| Security | Easier to secure (controlled environment) | Harder to secure (data travels over public networks) |
| Example | School network | The internet |
OCR Exam Tip: You may be asked to explain whether a given network is a LAN or a WAN. The key distinguishing factors are: geographical size and ownership. A LAN covers a small area and is owned by one organisation. A WAN covers a large area and typically uses third-party infrastructure.
There are many reasons for connecting computers into a network:
| Advantage | Explanation |
|---|---|
| Resource sharing | Devices can share printers, scanners, and internet connections |
| File sharing | Users can access shared files from any connected device |
| Communication | Email, instant messaging, and video conferencing |
| Centralised management | Software updates and security can be managed centrally |
| Centralised backup | Files stored on a server can be backed up centrally |
| Disadvantage | Explanation |
|---|---|
| Security risks | Networks can be targeted by hackers and malware |
| Cost | Network hardware, cabling, and maintenance cost money |
| Single point of failure | If the server goes down, all users may be affected |
| Complexity | Networks require specialist knowledge to set up and manage |
| Dependence | If the network fails, users may be unable to work |
Key Vocabulary: LAN, WAN, network, switch, router, ISP, Ethernet, WiFi, server.