Hello Matt,
I probably shouldn't tread into these waters, but...
Now, if you have a site which has more hosts than it can get external IPv4
addresses for, then as long as there are considerable numbers of IPv4 hosts a
site needs to interoperate with, *deploying IPv6 internally to the site does
the site basically no good at all*.
I think we've been through all this already and we explored it deeply at
the IAB Network Layer Workshop. One of the conclusions is that an IPv6
network NAT'ed to the IPv4 Internet isn't any better than what we have
today with
IPv4-NAT-IPv4, yet it will allow the given network to move to IPv6 in hopes
of someday connecting to other IPv6 networks without using NAT.
The last sentence isn't internally self-consistent. NATting from IPv6
to IPv4 creates the potential that you mention, and that is a benefit.
SO, it _is_ better.
If we get to a model where large new domains use IPv6 addressing
with NAT to global IPv4 address space, that would be quite useful.
Before too long, services will appear on the IPv6 network that
can't get the IPv4 global addresses they need. IPv6 clients will
work at least as well as privately-addressed IPv4 clients, so that
there is no downside to going IPv6. As this happens more and more,
the IPv6 domains will begin to dominate and interconnect efficiently.
Since the Internet continues to grow rapidly, today's dominant
deployment may well be tomorrow's sad legacy. Or not, depending
on who knows what?
So if you are NAT'd to the public Internet today, you shouldn't have a
problem with converting internally to IPv6. At least from an architectural
sense. :)
Indeed. And, to re-use an old bit of wisdom: "You're either part of
the problem, or part of the solution".
Regards,
Charlie P.