Wired Christianity Christianity in a wired world, as viewed by a Christian geek.


What is IPv6…and Why Should I Care?

If you haven't heard (and probably a number of you haven't), the Internet is running out of addresses. Well, sort of. Now, before I explain this for those unfamiliar, this is most assuredly not a case of Y2K all over again -- the sky is not falling, and Internet is not going to stop working as a result of this news. That said, let me see if I can explain what's going on here...

Homer Simpson, (c) Fox

Devices on the Internet communicate with each other by using their IP addresses. You've see them before -- four numbers, from 0-254, separated by a decimal (e.g., Without going too deeply into the historical details, this address format represents the 4th version of the IP protocol standards, commonly referred to as IPv4 (circa 1981). Given the range and arrangement of the numbers in these addresses, the design allowed for as many a 4 billion unique numbers, which sounded like a lot in the 1960's when this whole "Internet" thing was still largely conceptual. (I'll refrain from the Al Gore jokes, but know that I had at least three ready to go...)

Well, just like we said in the late 80's that we'd never fill up our 10 megabyte hard drives, the early designers of the Internet didn't see any issues with such a "limited" address space. However, in 1992, it was realized that almost 1/4 of the available 4 billion addresses had been consumed, so a new standard was drafted, which we know today as IPv6.

The most obvious and immediate differences between IPv4 and IPv6 we as users will notice are in the length and format of the address. IPv4 addresses, as described above, work out to be 32 bits in length. (In case you were wondering, 2 to the 32nd power is about 4 billion, hence the total of unique addresses...) IPv6 address, on the other hand, are 128 bits in length, and if you didn't know, 2 to the 128th power is an incredibly large number -- try 340 trillion, trillion, trillion unique addresses. (340,282,366,920,938,463,463,374,607,431,768,211,456 to be exact, but hey...who's counting?) To put that into perspective, consider this. Scientists tell us (whether we believe them or not) that the earth is about 4.5 billion years old. If we had been assigning IPv6 addresses at a rate of 1 billion per second since the earth was formed, we would have by now used up less than one trillionth of the address space. See, I told you it was a big number. Oh, and guess what -- it's no longer going to be those friendly 0-255 numbers we are used to working with. No, instead their going to be listed in hexadecimal form: 3ffe:0501:0008:0000:0260:97ff:fe40:efab. Fun, right? Picture calling your IT help desk or PC technical support service now. "Okay, ma'am/sir - can you tell me your IP address, please?" Fun stuff...

So, in summary, the world is running out of IPv4 space, and we're going to have to start using this new, long, complicated IPv6 thingy. What's the big deal? Well, here's the big deal. IPv4 and IPv6 are not directly compatible. In other words, hosts (i.e., computers) that have only IPv4 addresses can't communicated directly with hosts (i.e., other computers, servers, web sites, etc.) that have only IPv6 addresses. Now, did that get your attention? It should have, because in as little as a few months, you may find yourself needing to communicate with a businesses web site that only has an IPv6 address assigned to it. If your Internet Service Provider doesn't support IPv6, you may find yourself unable to reach this particular site.

What's more, there are a number of other components that we as Internet consumers take for granted because they (usually) just work, so many don't even know they're there: routing protocols, domain name services, network address translation, port address translation, access lists, etc. You can think of these services as (to reference The Wizard of Oz) "the little man behind the curtain," except without the magic they provide, your Internet simply doesn't work. And for your devices to continue their operation with the same level of reliability and performance that you're accustomed to today, they all need to be capable of handling the new address space. (The good news, fellow users, is that your computer's operating system is likely already capable of IPv6. In fact, recent versions of Windows, MacOS, and most of the Linux variants are already either IPv6-ready or are running both IPv6 and IPv4 in a "dual-stack" configuration (i.e., running both versions of the protocol simultaneously).)

At the end of the day, this whole ordeal likely isn't going to affect consumers all that much. There may be some spotty issues with web sites that have put off IPv6 enablement, or perhaps more of a concern will be their ISPs' implementation methods for IPv6 support. Nevertheless, the exhaustion of the old IPv4 space is definitely an issue worthy of the headlines it is and will continue getting. And, in the end when IPv6 is fully adopted and implemented by ISPs and businesses as it eventually will be, you'll be able to enjoy a number of benefits that are inherent in the new protocol standard. But I'll blog on that later. For now, it's late, and I'm going to sleep.