Cisco ICND2 – Describe IPv6 addresses

Some differences between IPv4 and IPv6:

  • Address size increased from 32bit – 128bit
  • 8 groups 4 hex characters each
  • Periods (.) replaced by colons (:)
  • Loopback 0:0:0:0:0:0:0:1 or ::1

Here is an example of a IPv6 address:


We can make the IPv6 a little easier to read by removing consecutive zeros and replacing them with :: we can only do this once.


We can take this further and drop the leading zeros, this can be done multiple of times.


IPv6-01 Making sense out of an IPv6 Address by Keith Barker
IPv6-02 Lov’n the Link Local Address by Keith Barker