Caitlin writes:
That's exactly why you want NAT/firewalling and
other existing mechanisms. These are devices
that do not require global addressability. In
fact they SHOULD NOT be globally addressable.
That's exactly why you only need one telephone per family. These are people who
don't need to be individually reachable. The head of the household can have one
telephone, and he or she can just physically seek out whoever else in the family
is wanted and put that person in front of the telephone.
That's also exactly why you only need one telephone per business. These are
employees who don't need to be individually reachable. The receptionist can
have one telephone, and he or she can just physically bring any other employee
who needs to be contacted to the phone in the reception area.
IPv6 needs to be justified on the number of nodes
that truly need a globally accessible public
address ...
IPv6, like any other expansion of the address space, is ultimately not something
that has to be justified, but simply something that cannot be avoided.
Additionally, the mere need for a unique public address doesn't even necessarily
justify IPv4. After all, we don't yet have four billion computers on the
Internet. But because of convenient but space-wasteful allocation policies for
the existing address space, we will appear to run out of addresses long before
the actual theoretical address space is exhausted, unless we resort to
allocating them sequentially until every slot is gone.
The allocation for IPv6 will inevitably be far more space-wasteful than that for
IPv4, human beings being the way they are, and so it will eventually be
exhausted as well, as hard as it may be to believe that now.
... not by insisting on counting devices that should
remain anonymous or under limited (and controlled)
visibility.
Similar arguments were advanced against private telephone lines. The most
consistent and serious error made by engineers in designing new systems is
dramatic underestimation of the capacity that will ultimately be required.