Dan Misener is a national technology columnist for CBC Radio afternoon shows, and one of the minds behind Spark with Nora Young.

In my books, Feb. 1, 2011, will go down as the day the internet got too big for its britches. The net has officially outgrown the scale of its original design.

Earlier in the day, the Internet Assigned Numbers Authority (IANA), the international organization that hands out IP addresses on a global scale, handed out two of the very last IP address blocks to APNIC, the internet registrar for the Asia-Pacific region.

This is the beginning of the end of IP addresses as we've known them, or as some have dubbed it, the first days of the IPocalypse.

So what exactly are we running out of? IP addresses.

If you don't know exactly what an IP address is, there's no need to worry, because it's a pretty simple concept.

Basically, an IP address is a unique number assigned to every device that's directly connected to the internet. Your computer at home, if it's directly connected to the internet, has an IP address. Your wireless router probably has an IP address. Your smartphone probably has an internet IP address. IP addresses are a big part of how devices on the internet are able to talk to one another.

4.3 billion addresses not enough

But here's the thing: there are only so many IP addresses that are possible. It's a finite number, about 4.3 billion addresses. And the last two big chunks of available IP addresses were just handed out.

So what happens when we run out of IP address? From the perspective of an internet user like you or me, nothing happens. The internet keeps on working.

But behind the scenes, there's a trickle-down effect, which will start to affect consumers in a few months. To understand what that means, you need to know a little bit about how IP addresses are distributed.

At a global scale, the world's 4.3 billion IP addresses are managed by an organization called IANA.

IANA divides those IP addresses among five different geographical regions: Africa, North America, Asia-Pacific, Europe and the Middle East, and Latin America.

Much like fruit distribution

At the regional level, those IP addresses get divided among internet service providers, universities and large corporations. Finally, internet service providers divide their share of IP addresses among their customers.

Or, to put it another way, imagine we're talking about apples. Delicious tasty apples.

Let's say I run a giant apple farm, and I'm in charge of the apple supply for the whole world. I divide up all the apples. I send some apples to Europe, to Africa, to Latin America, to North America and to the Asia-Pacific. These apples go to a warehouse, where they're distributed to markets and grocery stores and bodegas. Finally, they end up in your fridge.

If I suddenly shut down the world's supply of apples, there wouldn't be an immediate effect, because there'd still be some apples in the warehouses, there'd still be apples in the grocery stores, and there might still be apples in your fridge.

Obviously, apples and IP addresses are two very different things. Once you eat an apple, it's used up. IP addresses can be used again and again. But the distribution is similar.

At the end of the day, these developments in the world of IP addresses will stunt the growth of the internet, limiting the number of devices that can connect to it. Our appetite for internet-connected devices is growing. Many of us have computers, smartphones, tablets, internet-enabled television. The list goes on.

An unpronouncable number to come

The good news is that computer scientists have known about this limitation for years.

To prepare for it, they created a whole new addressing scheme, called IPv6 (or simply v6), which allows for a huge number of IP addresses.

In addition to the current 4.3 billion addresses, IPv6 allows for 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses. So, a lot.

Even though this new IPv6 system has been around for a while, most of the internet as we know it isn't ready for IPv6. ISPs have been particularly slow to adopt the new system.

The other really tricky bit is that the old IP address scheme and the new IPv6 address scheme aren't compatible with one another. It's likely that both systems will run alongside one another for years to come.

Another possible solution to IP address exhaustion is something called "Carrier-grade NAT," which allows existing IP addresses to be shared. Instead of me having my own IP address and my neighbour having her own IP address, we might share a single address.

That solution comes with its own set of challenges, some of which will be familiar to anyone who's ever shared a single phone number, or used a party-line telephone. Sharing can be tricky.

IPv6 seems to have the most momentum behind it. This June, a number of heavy-hitters like Google, Facebook and Yahoo are getting behind something called World IPv6 day, which is a sort of large scale "test flight" for the system.

Tips for the consumer

Vint Cerf, one of the fathers of the internet, has spoken out publicly about the importance of switching to IPv6. That said, IPv6 has its critics, particularly around the cost of implementation, security and surveillance. Security-wise, researcher Samuel Sotillo says IPv6 "creates as many new security problems as it solves old ones."

Unless you own or operate an internet service provider, there's not a lot you can do to impact the larger IP address landscape.

What you can do, though, is look at devices that you own to see if they'll work with these new IPv6 addresses. If and when your ISP starts to hand them out, you'll want to be ready. Start checking your computers, your smartphones, your home routers, your printers and your modems for IPv6 compatibility.

In some cases, you can get IPv6 support simply by updating your device's software. For instance, early versions of the iPhone didn't support IPv6, but the latest version of the software does.

Technical details aside, I think the most interesting thing about running out of IP addresses is what it says about where the internet is in 2011.

When IP addresses were first invented, the engineers never thought we'd need more than 4.3 billion. Yet, here we are, perilously close to that number.

IPocalypse or not, the internet is now bigger than its founding architects ever planned for.