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3.5 Fundamentals of Computer NetworksKey Facts

MAC Addresses (Media Access Control)

Part of IP & MAC Addresses · GCSE GCSE Computer Science revision

This key facts covers MAC Addresses (Media Access Control) within IP & MAC Addresses for GCSE Computer Science. Revise IP & MAC Addresses in 3.5 Fundamentals of Computer Networks for GCSE Computer Science with 15 exam-style questions and 18 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 3 of 9 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 3 of 9

Practice

15 questions

Recall

18 flashcards

MAC Addresses (Media Access Control)

What is a MAC Address?

A physical hardware address permanently burned into every Network Interface Card (NIC) at the factory. Uniquely identifies the physical device.

  • Purpose: Uniquely identify physical network hardware
  • Permanent: Cannot be changed (burned into NIC at manufacture)
  • 48 bits: 6 bytes (octets)
  • Operates at: Link layer (Layer 1 of TCP/IP)
  • Analogy: Like a fingerprint or serial number - identifies WHO device is

MAC Address Format:

  • 48 bits written as 12 hexadecimal digits
  • Format: AA:BB:CC:DD:EE:FF or AA-BB-CC-DD-EE-FF
  • Example: 00:1A:2B:3C:4D:5E
  • First 3 bytes (24 bits): Manufacturer ID (OUI - Organizationally Unique Identifier)
  • Last 3 bytes (24 bits): Device serial number (assigned by manufacturer)

MAC Address Examples:

00:1A:2B:3C:4D:5E - Apple device
00:50:56:XX:XX:XX - VMware virtual NIC
08:00:27:XX:XX:XX - VirtualBox virtual NIC
(First 3 bytes identify manufacturer)

Where MAC Addresses are Used:

  • Local delivery: Switches use MAC to deliver frames to correct device on LAN
  • ARP (Address Resolution Protocol): Maps IP addresses to MAC addresses
  • Network filtering: Routers can allow/block specific MAC addresses
  • Device tracking: MAC address can identify specific hardware

Keep building this topic

Read this section alongside the surrounding pages in IP & MAC Addresses. That gives you the full topic sequence instead of a single isolated revision point.

IP Addresses (Internet Protocol)IP vs MAC Addresses - Direct ComparisonThe Two Types of AddressesDeep Dive: Why Both Addresses are Needed

Practice Questions for IP & MAC Addresses

Which of the following correctly describes an IP address?

  • A. A permanent address burned into the NIC at the factory
  • B. A logical address that can change when connecting to a different network
  • C. A 48-bit address written as six pairs of hexadecimal digits
  • D. A physical address that uniquely identifies network hardware
1 markfoundation

Explain three differences between an IP address and a MAC address.

3 marksstandard

Quick Recall Flashcards

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IP Addresses (Internet Protocol)

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IP vs MAC Addresses - Direct Comparison