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The Two Types of Addresses
The Two Types of Addresses
Every device on a network needs TWO addresses: an IP address (logical, can change, like your home address - identifies WHERE you are) and a MAC address (physical, permanent, like your fingerprint - identifies WHO you are). IP addresses are used for routing across networks (Internet layer). MAC addresses are used for local delivery (Link layer). Think of sending a letter: the postal address (IP) gets it to the right town, the recipient's name (MAC) ensures it reaches the right person!
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Exam Tips - IP and MAC Addresses
Most common exam questions:
- "Difference IP vs MAC?" → IP can change (logical), MAC is permanent (physical/burned into hardware)
- "Why was IPv6 developed?" → IPv4 running out of addresses (4.3 billion not enough for all devices)
- "IPv4 vs IPv6 size?" → IPv4 = 32 bits, IPv6 = 128 bits
- "MAC address size?" → 48 bits (6 bytes in hexadecimal)
- "Which layer IP?" → Internet layer (Layer 2 of TCP/IP)
- "Which layer MAC?" → Link layer (Layer 1 of TCP/IP)
- "What is MAC address?" → Permanent physical address burned into NIC at factory
Key facts to memorize:
| Aspect | IP Address | MAC Address |
|---|---|---|
| Type | Logical (can change) | Physical (permanent) |
| Size | IPv4: 32-bit, IPv6: 128-bit | 48-bit |
| Format | 192.168.1.1 (IPv4) | AA:BB:CC:DD:EE:FF |
| Purpose | Routing (WHERE) | Local delivery (WHO) |
Common mistakes to avoid:
- Confusing which is permanent - MAC is permanent, IP can change!
- Forgetting IPv4 vs IPv6 bit sizes (32 vs 128)
- Not explaining WHY both needed (IP for routing, MAC for local delivery)
- Thinking MAC can be changed - it's burned into hardware at factory
Perfect exam answer:
"Explain the difference between IP and MAC addresses" (3 marks):
IP address is logical and can change (1 mark).
MAC address is physical and permanent, burned into NIC (1 mark).
IP used for routing across networks, MAC used for local delivery (1 mark).
Now try it yourself
Quiz · Question 1 of 15
Which of the following correctly describes an IP address?
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