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Cambridge IGCSE Computer Science · 0478

Topic 3: Hardware — Part 5

Network Hardware

Network Interface Card (NIC)

Purpose
Hardware inside a device required to access a network.
Function
Converts data into signals (voltages/pulses for wired, radio waves for wireless).
MAC address
Each NIC is assigned a unique MAC address during manufacture.

MAC addresses

Definition
A permanent hardware/physical identifier for devices on a local network.
Structure
Consists of two parts: a manufacturer code and a serial code.
Format
Usually written in hexadecimal to reduce character length.

Exam Traps

  • Do not confuse MAC and IP addresses — a MAC address is a permanent hardware identifier assigned during manufacture, whereas an IP address is allocated by the network and can change (static or dynamic).

IP addresses

Definition
Unique identifiers allocated by the network to each connected device.
Types
Can be static (fixed) or dynamic (changing).
Versions
IPv4 (32-bit, written as four decimal numbers separated by dots) vs. IPv6 (128-bit, written as eight groups of hex digits separated by colons).

Exam Traps

  • IPv4 uses four decimal groups (32-bit); IPv6 uses eight hex groups (128-bit) — do not mix the formats in an exam answer.

Routers

Role
Directs data packets between different networks.
Process
Reads the destination IP address of each packet and forwards it along the best path.
Other functions
Connects local networks to the internet and can assign local IP addresses via DHCP.

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