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AQA 8525 · Section 3.5 · Networks

Network
Hardware

Routers · Switches · WAPs · NICs · Transmission Media

CSZoneAQA GCSE Computer Science 8525
Network Devices

Routers, Switches, WAPs, NICs

Router — directs data packets between networks (e.g. your home LAN to the Internet). Assigns IP addresses via DHCP.
Switch — connects devices within a LAN. Sends data only to the intended device (uses MAC addresses). More efficient than a hub.
WAP (Wireless Access Point) — allows wireless devices to connect to a wired network. Extends Wi-Fi coverage.
NIC (Network Interface Card) — hardware in a device that enables it to connect to a network. Has a unique MAC address.
Transmission Media

How Data Travels Through a Network

Copper/Ethernet cable (Cat5/Cat6) — electrical signals. Cheap, fast, but limited distance (~100m). Subject to interference.
Fibre optic — light pulses through glass. Very fast, long distances, not affected by electromagnetic interference. Expensive to install.
Wi-Fi (radio waves) — wireless, convenient, mobile. Slower and less secure than wired. Range limited by walls/distance.
Bluetooth — short range (10m), low power. Used for PANs (keyboards, headphones, phones).
Switch vs Hub vs Router

Don't Confuse These!

Hub — broadcasts data to ALL connected devices. Inefficient, rarely used now. Creates unnecessary traffic.
Switch — sends data only to the intended device (MAC address table). Efficient. Standard in modern LANs.
Router — connects different networks (LAN-to-WAN). Routes packets using IP addresses. Your broadband router does both routing and switching.
Exam Practice

Have a go at this question

AQA-style question
Describe the role of a router in a network.
2 marks
A router directs data packets between different networks [1] using IP addresses to determine the best path for each packet to reach its destination [1].
Key Takeaways

What to Remember

Router = connects networks (uses IP) · Switch = connects devices in LAN (uses MAC)
WAP provides wireless access · NIC is the hardware that lets a device connect
Fibre optic: fastest, longest range · Copper: cheaper · Wi-Fi: wireless but slower
Hub = broadcasts to ALL (inefficient). Switch = sends to correct device only