IPv6 Addresses
IPv6 addresses are 128 bits long and represented by groups of 1-4 hex characters separated by a : (aka a "hextet“, or more formally a “hexadectet”).
- 2001:0db8:0000:0000:0000:ff00:0042:8329
Using the recommendations in RFC5952 section 4.2 we can shorten that IPv6 address.
Leading 0's in a grouping may be omitted.
- 2001:db8:0:0:0:ff00:42:8329
It may contain at MOST a single :: which represents the largest contiguous block (longer than 16 bits) of 0's in the address
- 2001:db8::ff00:42:8329
If multiple contiguous blocks are the same length, shorten the left most one
- 2001:0:0:AAAA:0:0:B:CC becomes 2001::AAAA:0:0:B:CC
If the contiguous 0's only encompass a single hextet, do NOT replace it with a ::
- The 2nd hextet in A:0:BBBB:CCC:D0:22:FF:4412 should never be reduced with a ::
The Layer 2 (Ethernet) multicast address for IPv6 is 33:33:00:00:00:01