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Knowledge organisers / Wired and wireless networks, protocols and layers

IP addressing and MAC addressing

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Knowledge organiser

Wired and wireless networks, protocols and layers

1.3.2c

What you need to know

IP addresses and MAC addresses are both used to identify devices on networks, but they work differently. IP addresses can change and are used for routing data across networks; MAC addresses are permanent and identify hardware.

Key points

  • Definition:IP Address: a unique number assigned to a device on a network, used to identify and locate it. Can change (e.g. when connecting to different networks).
  • IPv4 addresses are 32-bit: four decimal numbers separated by dots (e.g. 192.168.1.1).
  • IPv6 addresses are 128-bit: eight groups of four hexadecimal digits separated by colons.
  • Definition:MAC Address: a unique, permanent identifier assigned to a device's NIC during manufacture. 12-digit hexadecimal number (e.g. 00:1A:2B:3C:4D:5E).
  • IP addresses are used for ROUTING data across networks (logical address). MAC addresses identify the SPECIFIC DEVICE on a local network (physical address).
  • Exam Tip:Key difference — IP addresses can CHANGE; MAC addresses are PERMANENT (assigned during manufacture).
  • Common Mistake:Saying MAC addresses can be changed by the user. They are permanently burned into the NIC hardware.
  • Exam Tip:MAC address format: 6 groups of 2-digit hex numbers separated by colons or hyphens (e.g. 00:1A:2B:3C:4D:5E). 48 bits total. First half = manufacturer ID, second half = serial number.
  • Exam Tip:IPv4 = 4 groups of 0-255 separated by DOTS. IPv6 = 8 groups of hex separated by COLONS. Common error: giving 6 groups for IPv6 or using dots instead of colons.