CertiGuide to Network+  9  Chapter 0101:  TCP/IP

XVI  Classless Inter-Domain Routing 1 2 3 4 XVIII  CIDR and IPv6

IPv6 Addressing

Two changes in the framework of IPv6 make it clear this is not your grandfather’s IP. The change from 32-bits to 128-bits makes for an example on paper which is either in type so tiny you would have a difficult time reading it, or the example would have to break over the width of the paper. The difficulty of representing 128-bit addresses in the 1’s and 0’s that make them up at the lowest levels gives rise to the second huge change in IPv6.

Instead of using Base 10 (0-9) or what we call in the classroom, “checkbook math”, the new standard uses Base 16 or Hex math when writing IP addresses (0-F). If you have read our Success with: A+ Core Technologies book, you are comfortable with Hexadecimal math, and can continue. If you have not read that book, we have written a small segment and included it in Appendix B. Please stop here and go to that appendix to discover how counting to 16 in a single column of numbers works, then return to this section.

In IPv6 there are three conventional methods to represent IPv6 addresses as text strings. The preferred form is x:x:x:x:x:x:x:x, with each x being a one to four digit hexadecimal value of one of the eight 16-bit pieces of the address.

For example, one legal IPv6 address is::

FEDC:BA98:7654:3210:ABCD:EF89:4567:3210

Another example of a legal IPv6 address would be:

1022:0:0:0:0:802:201A:312A

XVI  Classless Inter-Domain Routing 1 2 3 4 XVIII  CIDR and IPv6