[ppml] IPv6>>32

>Final consideration, do you really believe in 50-100 years we will still be
>using IP at all ?.

This is a central question to the entire topic of IPv6. My best answer is 
"I really don't
know" which, logically, admits the possibility of "yes". Some technologies 
are "sticky"
simply because they work and the cost of universal adoption of alternatives are
just too high. So over a century later we still use the internal 
consumption engine,
decades later we still use amplitude modulated radio signalling, and so on. 
It may well
be the case that packet switching is one of these sticky technologies, in 
which case
the address architecture is indeed a critical issue.

I'm not sure that we should be in the business of built in obsolescence, 
and certainly not
if we can buy the additional time without undue pain. The presentation at 
ARIN XV
looked at the HD ratio and the subnet boundary as potential points of 
variation in
the address plan that could admit more efficient utilization without 
alteration to the
overall IPv6 architecture and without undue need to alter existing equipment,
software or deployments such as they are. Its certainly the case that 
alteration of
the length of the global identifier could admit vastly greater address 
utilization but
of course the question here is, simply, whether the gain is worth the pain.

Geoff