Network Hardware (Copy)
IGCSE / O Level Computer Science Cheat Sheet
Topic: 3.4 Network Hardware
🧩 Key Network Hardware Components
| Device | Purpose |
|---|---|
| NIC (Network Interface Card) | Allows a device to connect to a network via cable or wireless |
| Router | Routes data between networks; connects LAN to the internet |
| Switch | Connects multiple devices in a LAN; forwards data only to destination |
| Hub | Broadcasts data to all connected devices (less efficient than a switch) |
| Modem | Modulates and demodulates digital signals over phone lines |
🏷️ MAC Address (Media Access Control)
- Unique hardware address assigned to each NIC
- Set at manufacture – cannot be changed
- Format: 6 pairs of hexadecimal digits (e.g.
00:A1:B2:C3:D4:E5) - Used for local identification in a network
🌐 IP Address (Internet Protocol)
- Logical address assigned to a device on a network
- Can be static or dynamic
| Type | Description |
|---|---|
| Static IP | Permanently assigned, never changes |
| Dynamic IP | Temporarily assigned by a DHCP server |
🆚 IPv4 vs IPv6
| Feature | IPv4 | IPv6 |
|---|---|---|
| Format | 32-bit (e.g. 192.168.0.1) | 128-bit (e.g. 2001:0db8::1) |
| Addresses | ~4.3 billion | ~3.4 × 10³⁸ |
| Usage | Common, older | Newer, for expanding internet devices |
📡 Router Functions
| Function | Description |
|---|---|
| Packet routing | Sends data between networks |
| Local IP assignment | Allocates dynamic IPs to devices (DHCP) |
| Firewall functionality | Blocks unauthorized access |
| NAT (Network Address Translation) | Translates local IPs to public IPs |
| Wireless Access Point (WAP) | Provides Wi-Fi (in wireless routers) |