[address-policy-wg] IPv6 allocations for 6RD

> Fair enough, I'll bite. Given 2^32(or 4 billion) IPv4 
> addresses, and say, 4 million IP's allocated to the average 
> ISP (I'm being generous
> here) there's your 0.1%. The rest of the space will go unused 
> since we're using 32 bits to identify these sparse blocks in 
> the v4->v6 translation. Not counting customer /56s, 48s, /60s 
> or whatever.

But customers, and /56s are the essential things to count.
Again, you just throw in the number 4 million without explaining
where it comes from. IPv4 ISPs come in all sizes with 
one /24 allocation and some with many allocations of sizes
ranging from /17 to /12.

Counting IP addresses in IPv6 makes no sense. The addressing
hierarchy of IPv6 is designed to have large blocks of unused
and unusable addresses. This is both to allow for expansion
without changing the network architecture, and to allow for
automated address assignment functions which rely on large
sparse number spaces to avoid collisions.

--Michael Dillon