[ppml] trade in your IPv4 block for an IPv6?

[Paul Vixie]

what if someone could get PI IPv6 space by agreeing to return PI IPv4 space?

not the same day, mind you.  within two years, perhaps.  or five years.  an
exchange rate would have to be established, like "if you return a V4 /16, we
will give you a V6 /48" or even "we'll give you a V6 /(49-N) for the N V4
/16's you return".  the goal would be to shrink or keep stable the size of
the routing table in dual stacked routers, while getting V4 space back that
we can use for address lifetime extension later when V4 space gets short.

(i'm trying to think of some early adopter advantages that would have
beneficial side effects.)