Know and understand Local Area Network (LAN), Wireless Local Area Network (WLAN), Wide Area Network (WAN) and the differences between these networks

4. Networks and the Effects of Using Them

Learning Objective

Know and understand Local Area Network (LAN), Wireless Local Area Network (WLAN), Wide Area Network (WAN) and the differences between these networks.

Key Definitions

• Network: A collection of computers, servers, and other devices that are linked together to share resources and information.
• Local Area Network (LAN): A network that covers a small geographical area such as a single building, floor, or campus.
• Wireless Local Area Network (WLAN): A LAN that uses radio waves (Wi‑Fi) instead of cables to connect devices.
• Wide Area Network (WAN): A network that spans a large geographical area, often connecting multiple LANs or WLANs across cities, countries, or continents.

Characteristics of Each Network Type

Advantages and Disadvantages

Local Area Network (LAN)

• High data transfer speeds.
• Low latency, suitable for real‑time applications.
• Relatively easy to secure with physical controls.
• Requires cabling – can be costly and inflexible for changes.

Wireless LAN (WLAN)

• Mobility – users can connect from anywhere within coverage.
• Quick deployment, especially in historic or rented buildings.
• Potential interference from other devices (microwaves, Bluetooth).
• Security must be robust (encryption, strong passwords) because signals travel through the air.

Wide Area Network (WAN)

• Connects geographically dispersed sites, enabling collaboration.
• Provides access to cloud services and the Internet.
• Higher latency and lower speeds compared with LAN/WLAN.
• Reliance on external providers can increase cost and reduce control.

Effects of Using Networks

1. Resource Sharing: Enables multiple users to share printers, storage, and applications, reducing hardware costs.
2. Communication: Facilitates email, instant messaging, video conferencing, and collaborative tools, improving productivity.
3. Data Management: Centralised databases and servers simplify backup, security management, and data integrity.
4. Scalability: Networks can be expanded by adding devices or extending coverage (e.g., adding a new LAN segment or a WAN link).
5. Security Risks: Increased exposure to viruses, hacking, and data interception; requires firewalls, encryption, and regular updates.
6. Cost Implications: Initial setup (cabling, hardware) and ongoing expenses (maintenance, ISP fees) must be balanced against benefits.
7. Reliability: Network downtime can halt business processes; redundancy (e.g., backup links, RAID storage) mitigates this risk.

Typical Real‑World Examples

• School computer lab – wired LAN connecting PCs to a server for file storage.
• Café offering free Wi‑Fi – WLAN providing internet access to customers.
• Multinational company – WAN linking offices in London, New York, and Tokyo via leased fibre lines.

Suggested Diagram

Summary Checklist

• Identify the physical scope of a LAN, WLAN, and WAN.
• Explain the main transmission media for each network type.
• Compare speed, latency, and typical uses.
• List at least three advantages and three disadvantages for each network.
• Describe the key effects of networking on resource sharing, communication, security, and cost.