Introduction to Spanning-Tree

Hello Patrick

This is an excellent question that we don’t often address directly. Remember that MAC addresses are essentially numbers. By convention, MAC addresses are written in Hexidecimal. Computers and network devices actually read MAC addresses as binary. We can even write out a MAC address in decimal format, although we never do that because it has no use to us.

So a MAC address of 00:00:00:00:00:01, if simply viewed as a number, is smaller than 00:00:00:00:00:02. Similarly AB:00:00:00:00:00 is smaller than AC:00:00:00:00:00. Some more examples:

  • AB:CD:EF:12:34:56 is larger than AB:CD:EF:12:34:11
  • 00:00:00:55:55:55 is larger than 00:00:00:44:55:55
  • FF:FF:FF:FF:FF:FF is larger than 00:00:00:00:00:00

IPv4 addresses are also often used as tiebreakers in the functionality of some Layer 3 protocols, where the higher or lower IP address “wins”. Such a mechanism is more readily understandable because IPv4 uses the dotted decimal format, which we as humans are more familiar with.

I hope this has been helpful!

Laz