NIC (Network Interface Card): hardware that connects a device to a network. Each NIC has a unique MAC address. Can be wired (Ethernet) or wireless (Wi-Fi).
Router: connects different networks. Directs packets between a LAN and the internet using IP addresses. Contains a routing table.
Switch: connects devices within a LAN. Sends data only to the intended device (using MAC addresses). More efficient than a hub.
Hub, WAP & Repeater
Supporting Network Devices
Hub: broadcasts data to all devices on the LAN. Inefficient — causes collisions. Mostly replaced by switches.
WAP (Wireless Access Point): allows wireless devices to connect to the wired network. Extends network coverage wirelessly.
Repeater: amplifies and regenerates signals to extend network range over long distances.
Bridge: connects two separate network segments. Filters traffic so only relevant data crosses between segments.
IP & MAC Addresses
Identifying Devices on a Network
IP address: logical address assigned to a device on a network. Can change (dynamic) or be fixed (static). Used by routers to direct packets.
MAC address: physical address permanently assigned to a NIC by the manufacturer. 48-bit hexadecimal. Used by switches to direct frames within a LAN.
IPv4: 32-bit (e.g. 192.168.1.1); IPv6: 128-bit (e.g. 2001:0db8::1) — more addresses available
Exam Practice
Have a go at this question
Cambridge IGCSE 0478 style
Describe one difference between a switch and a hub when transmitting data within a LAN.
2 marks
A switch sends data only to the intended device using MAC addresses [1], whereas a hub broadcasts data to all devices on the network regardless of destination [1].
Key Takeaways
What to Remember
NIC: connects device to network with unique MAC address
Router: joins networks using IP addresses; Switch: joins LAN devices using MAC addresses
WAP: wireless access; Repeater: extends range; Hub: broadcasts to all (inefficient)
IP: logical, can change; MAC: physical, permanent (assigned by manufacturer)