[ppml] PIv6 for legacy holders (/w RSA + efficient use)

[Paul Vixie]

> > the problem with this is that any IPv4-only target (like a web site) will
> > not be reachable to any IPv6-only initiator.
> 
> I don't see this as a big concern: "IPv6-only" does not preclude the use of
> RFC 1918 and NAT if you assume ISPs will continue to be able to provide /32s
> as IPv4 NAT end points for the foreseeable future (a safe bet, I'd argue).
> One might even envision a business model where ISPs obtain additional
> revenues by leasing IPv4 PA /32s for customer servers...

this sounds fatalistic.  like "it is our destiny to squeeze every last
possible route into the V4 DFZ" and "it is our destiny to use V4 as long as
humanly possible" and "it is our destiny to use V4 until the additive and
inertial costs of switching to V6 are terrible to witness".

for those of you who feel that human nature dictates a tipping point be
reached and surpassed, either in V4/V6 transition or global warming or
whatever, some set of options will appear to be on vs. off the table.

for me, who still thinks nonfatalistic thoughts about the V4/V6 transition,
a different set of options will appear to be on vs. off the table.