My first reaction is to say that clinging to IPv4 addressing is fundamentally wrong-headed and only puts off the inevitable move to IPv6. Sooner or later, you'll have to do it. But even the biggest companies are resisting. IPv4 use is so entrenched that in 2011, Microsoft saw fit to buy 666,624 IPv4 addresses from Nortel during the latter's bankruptcy proceedings for $7.5 million, or $11.25 per address. That was shortly after the Internet Assigned Numbers Authority (IANA) handed out the last five class A address blocks, one to each Regional Internet Registry (RIR), in February 2011. The bottom line is that IPv4 is overstaying its welcome.
June 8 was the second Internet Society Worldwide IPv6 Launch Day, and the measurements taken of actual traffic show little IPv6 uptake. An Arbor Networks graph shows less than .2% of the traffic the company measured was IPv6. That's up from a peak of .04%, which occurred on the first Worldwide IPv6 Day in 2011; hardly a blip in a year.
In fact, an InformationWeek IPv6 survey of 681 business technology professionals shows deployment among organizations is slow, and a whopping 38% have no plans to run IPv6 for the foreseeable future. It's worse on the broadband side. As far as I know, Comcast is the only U.S. broadband provider rolling out IPv6 to its customers.
This all leads to one conclusion: Transitioning to IPv6 will take much, much longer than anyone expects, mostly because there is no clear reason to move to IPv6 anytime soon. And yet we need to transition to IPv6 at some point in the future. It's that last bit--"some point in the future"--that relegates IPv6 migration to the bottom of the to-do list. Y2K had a clear deadline: Dec. 31, 1999, at 11:59 pm. The deadline for IPv4 exhaustion? "Later."
Without a clear deadline, the various actors in IPv6 such as the carriers, hosting providers, cloud providers, broadband providers, mobile network operators, consumer router vendors like Cisco/Linksys, Apple, SonicWall and others, and networked equipment like cameras, printers, mobile phones and the like, have little reason to proceed quickly toward IPv6 support. Thankfully, operating systems from Apple and Microsoft as well as various versions of Linux support IPv6 natively. But they're the exception, with all those other huge gaps still to be closed.
One question that's surely stopped IPv6 projects in their tracks: Why start a migration now, if some dependency outside your control is going to stop you in the future? Each and every one of you reading this is a customer of service providers and equipment vendors. It's time to use your voice and demand an IPv6 migration strategy that you can plan on. Without all of those other parts in place, you'll be stuck paying more and more for IPv4 addresses, and getting less and less.