MAC Addresses & IP Addresses (Cambridge (CIE) IGCSE Computer Science)

Revision Note

James Woodhouse

Written by: James Woodhouse

Reviewed by: Lucy Kirkham

  • Devices on a network send and receive data, a device needs an address to ensure it sends data to the correct place

  • There are two types of network address systems:

    • MAC Address 

    • IP Address

MAC Addresses

What is a MAC address?

  • A MAC (Media Access Control) address is a unique identifier given to devices which communicate over a local area network (LAN)

  • A network interface card is given a MAC address at the point of manufacture

  • MAC addresses are static, meaning they can never change

  • MAC addresses make it possible for switches to efficiently forward data to the intended recipient

  • Any device that contains a Network Interface Card (NIC) has a MAC address assigned during manufacturing

  • A device connecting to a local network already has a MAC address, if it moves to a different network then the MAC address will stay the same

mac-address-1
  • A MAC address is represented as 12 hexadecimal digits (48 bits), usually grouped in pairs

  • The first three pairs are the manufacturer ID number (OUI) and the last three pairs are the serial number of the network interface card (NIC)

  • There are enough unique MAC addresses for roughly 281 trillion devices

IP Addresses

What is an IP address?

  • An IP (Internet Protocol) address is a unique identifier given to devices which communicate over the Internet (WAN)

  • IP addresses can be static, meaning they stay the same or dynamic, meaning they can change

  • IP addresses make it possible to deliver data to the right device

  • A device connecting to a network will be given an IP address, if it moves to a different network then the IP address will change

IPv4

  • Internet Protocol version 4 is represented as 4 blocks of denary numbers between 0 and 255, separated by full stops

  • Each block is one byte (8 bits), each address is 4 bytes (32 bits)

ipv4
  • IPv4 provides over 4 billion unique addresses (232), however, with over 7 billion people and countless devices per person, a solution was needed

IPv6

  • Internet Protocol version 6 is represented as 8 blocks of 4 hexadecimal digits, separated by colons

  • Each block is 2 bytes (16 bits), each address is 16 bytes (128 bits)

-ipv6
  • IPv6 could provide over one billion unique addresses for every person on the planet (2128)

Worked Example

Computers in a network can be identified using both IP addresses and MAC addresses.

Describe two differences between IP addresses and MAC addresses [2]

Answer

  • IP address is dynamic/can change // MAC address is static/cannot change

  • IP address is used to communicate on a WAN/Internet // MAC address is used to communicate on a LAN

Last updated:

You've read 0 of your 10 free revision notes

Unlock more, it's free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

James Woodhouse

Author: James Woodhouse

Expertise: Computer Science

James graduated from the University of Sunderland with a degree in ICT and Computing education. He has over 14 years of experience both teaching and leading in Computer Science, specialising in teaching GCSE and A-level. James has held various leadership roles, including Head of Computer Science and coordinator positions for Key Stage 3 and Key Stage 4. James has a keen interest in networking security and technologies aimed at preventing security breaches.

Lucy Kirkham

Author: Lucy Kirkham

Expertise: Head of STEM

Lucy has been a passionate Maths teacher for over 12 years, teaching maths across the UK and abroad helping to engage, interest and develop confidence in the subject at all levels.Working as a Head of Department and then Director of Maths, Lucy has advised schools and academy trusts in both Scotland and the East Midlands, where her role was to support and coach teachers to improve Maths teaching for all.