GCSE Computer Science Networks Explained

May 26, 2026

What are Computer Networks?

A computer network is a collection of computers connected together to share resources and communicate. Networks are essential to modern computing and appear throughout the GCSE Computer Science exam.

LANs vs WANs

LAN (Local Area Network): Computers in the same building or close proximity (school, office, home). Fast, low latency, covers small geographical area.

WAN (Wide Area Network): Computers across cities or countries (Internet). Slower, higher latency, covers large geographical areas. Connected via leased lines or public networks.

The TCP/IP Model

The internet uses the TCP/IP model with 4 layers:

• Application Layer: HTTP, HTTPS, FTP, Email (SMTP/POP3)
• Transport Layer: TCP and UDP protocols
• Internet Layer: IP addresses, routers
• Link Layer: Physical connections, MAC addresses

IP Addresses

IPv4 addresses are 32-bit numbers written as four octets: 192.168.1.1

Each octet ranges from 0-255, giving over 4 billion possible addresses. DNS (Domain Name System) translates domain names (google.com) into IP addresses.

Cybersecurity & Networks

Networks face constant threats. Key security concepts:

• Firewalls: Block unauthorized traffic
• Encryption: HTTPS secures web traffic
• Passwords & Authentication: Control access
• Malware & Viruses: Protect against with antivirus software