Cambridge IGCSE Computer Science (0478) · lesson 12 of 35 · 25 min
Network Hardware Devices
Switch vs Hub
A hub receives a frame on one port and broadcasts it to every other port. Every device sees every frame — this wastes bandwidth and causes collisions.
A switch maintains a MAC address table mapping each MAC address to a port. It forwards frames only to the correct destination port. This dramatically reduces collisions and improves network performance. Switches have almost entirely replaced hubs in modern networks.
Router — Connecting Networks
A router operates at Layer 3 (Network layer) and makes forwarding decisions based on IP addresses. It maintains a routing table listing known networks and the best path to reach them. Home routers typically combine a router, switch, WAP, and modem in one device.
Which device uses MAC addresses to forward frames only to the correct port?
- Hub
- Router
- Switch
- WAP
Answer: Switch
A switch maintains a MAC address table and forwards frames intelligently.
What does a router use to make forwarding decisions?
- MAC addresses
- IP addresses
- Port numbers
- Serial numbers
Answer: IP addresses
Routers operate at Layer 3 and use IP addresses.
What is the purpose of a WAP?
- Connect two different networks
- Provide wireless access to a wired LAN
- Amplify electrical signals
- Assign IP addresses
Answer: Provide wireless access to a wired LAN
A WAP bridges wireless clients to the wired network.
Previous lesson: Wired and wireless transmission media
Back to Cambridge IGCSE Computer Science (0478)
Next lesson: The Internet: IP addresses, DNS, and packets