||The problem with
determining when all 3.7B IPv4 addresses will be in use overlooks the fact
that it becomes increasingly difficult to make progress. As Christian Huitema pointed out in
RFC-1715, each level of delegation will be unable to achieve perfect
utilization of the address space so each must introduce a level of addressing
inefficiency. The distant end of this
scenario would suggest going into each /24 network and ensuring all 254
addresses are actually being used; this seems at best unlikely.