[ppml] IPv4 wind-down

[Martin Hannigan]

> Shortly we will be burning through 2+ /8's per month, so
> the logistics of reclaiming space will be challenged to
> keep up, even if there are blocks that add up to that
> much. 

An above ground v4 trade would be helpful. Allowing V4 to be
treated as property, at least for legacy space, would be
required. The economics of that are interesting, and the
outcome predictable. Seems like a smoother transition
than tossing a bomb into the problem like the aforementioned
policy seems 
to do, IMHO.

-M<