Spec & Goals 3 min
AQA Spec 3.5.1.1 — Networks: definition, advantages/disadvantages, PAN / LAN / WAN
By the end of this lesson you can:
- Define what a computer network is.
- Give advantages and disadvantages of using a network.
- Describe the three main network types — PAN, LAN and WAN.
Warm-Up 5 min
You finished Unit 4 by looking at a single computer's architecture. Real computers rarely work alone — they are joined together into networks. This unit is all about how.
Quick starter
Name three devices in your home that connect to the same Wi-Fi. What can they do because they are connected that they could not do alone?
Reveal the idea
Phones, laptops, a smart TV, a printer… Connected, they can share one internet link, share files, and send to one printer. Sharing resources is the whole point of a network.
Key Concept — what a network is 14 min
A computer network is two or more devices connected together so they can communicate and share resources (data, an internet connection, a printer, storage).
Why use a network? (advantages)
- Share hardware — one printer or scanner serves many computers.
- Share data and files — users access the same files from any connected device.
- Share an internet connection — one connection serves the whole site.
- Communicate — email, messaging and video calls between users.
- Central control — software updates, backups and security managed in one place.
The trade-offs (disadvantages)
- Cost — cabling, switches, routers and servers cost money to buy and run.
- Security risk — malware and hackers can spread across connected devices.
- Dependency — if the server or connection fails, many users are affected at once.
- Management — networks need skilled staff to set up and maintain.
The three network types — by size
AQA names three types, smallest to largest:
| Type | Stands for | Scale | Example |
|---|---|---|---|
| PAN | Personal Area Network | One person, a few metres | A phone linked to wireless earbuds and a smartwatch by Bluetooth. |
| LAN | Local Area Network | One site / building | A school in Ipoh; one office; a home. |
| WAN | Wide Area Network | Large geographic area | A bank's branches across Malaysia; the internet itself. |
Worked Example — naming the network 12 min
Problem: For each scenario, name the network type (PAN / LAN / WAN) and justify it.
| Scenario | Type | Why |
|---|---|---|
| Aisyah's phone streams music to her Bluetooth earbuds. | PAN | Devices around one person, a few metres apart. |
| Every computer in a Penang school office shares one printer over cables the school owns. | LAN | One site; the school owns the connecting hardware. |
| A bank links its KL, JB and Kuching branches over leased lines. | WAN | Large geographic area; uses third-party infrastructure. |
Try It Yourself 12 min
Goal: Write what each abbreviation stands for: PAN, LAN, WAN.
Hint: the middle word is always "Area".
Goal: Give two advantages and two disadvantages of installing a network in a small kedai with five computers.
Hint: think sharing vs cost/security.
Goal: Explain the two key differences between a LAN and a WAN.
Hint: one is about distance; one is about who owns the cables.
📝 Exam Practice 10 min
The command word and the marks tell you how much to write.
Define the term computer network.
Mark scheme
- Two or more devices connected together (1) to communicate / share data / share resources (accept either idea for the mark).
Describe one advantage and one disadvantage of connecting a school's computers into a network.
Mark scheme
- Advantage — e.g. share hardware (one printer) / share files / share internet / central backups & updates (1).
- Disadvantage — e.g. cost of equipment / malware can spread / failure affects many users (1).
A company links its offices in Kuala Lumpur and Johor Bahru. Explain why this is a WAN and not a LAN.
Mark scheme
- It covers a large geographic area / the offices are far apart (1).
- It uses third-party / leased infrastructure (e.g. telephone lines) the company does not own, whereas a LAN is one site with hardware the organisation owns (1).
Recap & Key Terms 3 min
A network connects devices so they can share data and resources. Networks bring sharing and central control, but cost money and add security risk. By scale: a PAN covers one person, a LAN one site (hardware you own), and a WAN a large area (third-party infrastructure).
- Computer network
- Two or more devices connected so they can communicate and share data and resources.
- PAN
- Personal Area Network — devices around one person, a few metres apart (e.g. Bluetooth).
- LAN
- Local Area Network — one small site; the organisation owns the connecting hardware.
- WAN
- Wide Area Network — a large geographic area, using third-party infrastructure the organisation does not own.
Homework 1 min
Task (≤ 15 min): A chain of three mamak restaurants wants its tills to share one stock database. State the network type they need, and give two advantages and one disadvantage of networking the tills.
Model answer
The restaurants are in different locations, so they need a WAN (linked over third-party lines / the internet). Advantages: tills share one up-to-date stock database; central backups and updates; staff can compare sales across branches. Disadvantage: if the connection fails, the tills lose access to the shared database (also accept: cost, or malware spreading between sites).
Award marks for: correct type — WAN (1); two valid advantages (2); one valid disadvantage (1).