"On the topic of confusing netmasks, IPv6 addresses certainly
have a place. The netmask isn't really an issue—the same
concept applies, just with larger numbers to remember. The real
problem lies within the address representation itself; the IETF
seemed to take pride in creating confusion. Typically an IPv6
address is represented in hex, or base-16. Our old friend IPv4
could represent an IP address in hex too, which would look like
B.B.B.B for the address 11.11.11.11. Unfortunately, IPv6 isn't
quite that nice looking. To represent 128 bits, IPv6 normally
breaks up the address into eight 16-bit segments."