You may have seen a recent news report about the American Registry for Internet Numbers (ARIN) having to refuse a request for a block of Internet Protocol v4 addresses due to lack of inventory, the first time such an event has happened. According to a CBS News story, ARIN's CIO Richard Jimmerson stated that the organization is only weeks away from having no IPv4 addresses left to assign.

There have been cries of "Wolf!"� over the last few years concerning the remaining inventory of IPv4 addresses, with reports as far back as 2010 claiming that the IPv4 well was running dry. But, the predicted end-of-the-line for IPv4 always managed to creep ahead to some nebulous, unspecified time in the future. Without a defined end date to provoke a sense of urgency, the connected world has largely ignored the IPv4 issue.

The good news is that the replacement for IPv4 has been waiting in the wings for at least twenty years: IPv6. The next generation of the Internet Protocol is set to alleviate the continued demand for IP addresses.

IPv6 uses 128-bit addresses, compared to IPv4's 32-bit addresses. This allows for a huge number of possible IPv6 addresses, 3.4x1038 to be exact. This is way more IP addresses than the world will need for well, hopefully for good. If the global population reaches a point where it uses up 340 undecillion IP addresses, we'd better be colonizing other solar systems by then.

The current IPv4 crisis could have been avoided if more aggressive adoption of IPv6 had taken place in the last two decades. Instead, the networked world has largely been content to suck the last few drops of IPv4 addresses out of the well [1].

But, the demand for IPv4 addresses has been exacerbated by the awkwardly-labelled Internet of Things (IoT) movement. Smart houses, smart vehicles, and the ever-growing network of official and unofficial drones are accelerating the inevitable depletion of IPv4 addresses, and there are millions of additional IoT devices expected to join the LAN/WAN party in the not too distant future.

While the recent ARIN news story may not be as dire as it sounds, now is the time for networking techs and other IT professionals to get acquainted with IPv6 basics. Here are a few nuggets to get you started:

1) An IPv6 address consists of eight groups of four hexadecimal numbers, with each group separated by a colon. A sample IPv6 address is 2001:cdba:0000:0000:0000:0000:3257:9652.
2) Any group consisting of four zeroes can be abbreviated as "�0' or removed entirely. For example, the IPv6 address given above could be shortened to 2001:cdba:3257:9652.
3) IPv6 addresses are mapped to DNS hostnames using AAAA resource records, sometimes referred to as quad-A records.
4) Current operating systems with native support for IPv6 include Windows, Red Hat Enterprise Linux, Mac OS X, iOS, and Ubuntu.
5) IPv6 addresses can be subnetted. And yes, there are IPv6 subnet calculators available. (Phew!)

To learn more about IPv6, check out this web page on Microsoft's TechNet site. It contains a great selection of links to articles and white papers about IPv6. A good starting point on the TechNet page is the Introduction to IPv6 paper which was written in 2002 and updated in 2008.

[1] BTW, this is pretty much how the global fossil fuel crisis is going to play out.