A2.1.3 — Network Devices

Devices

Device	What it does	Key detail	TCP/IP Layer
Gateway	Bridges two networks using different protocols.	Translates data formats between networks.	Application
Firewall	Monitors and controls network traffic based on security rules.	Hardware or software. Blocks unauthorised access.	All layers
Modem	Converts digital to analogue signals for transmission over phone/broadband lines.	Bridges digital networks and analogue phone systems.	Link
NIC	Connects a device to the physical network.	Converts electical signals to digital data.	Link
Router	Directs packets between different networks using IP addresses.	Uses routing table to find best next hop.	Internet
Switch	Connects devices within a LAN and forwards frames to the correct device.	Uses MAC address table to forward frames.	Link
WAP	Extends wired network to wireless devices.	Converts Ethernet ? radio signals. Supports WPA/WPA2/WPA3.	Link

Hardware firewall: Standalone physical unit. Sits between the entire network and the outside world. Handles all incoming/outgoing traffic centrally. Does not impact individual device performance.
Software firewall: Installed as an application on a single device. Controls traffic at the device level. Useful for protecting individual machines from internal threats.