IPv6 is Coming--Just in Time

As the world runs out of Internet addresses, network engineers prepare to switch over to the new protocol

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Steven Cherry: Hi, this is Steven Cherry for IEEE Spectrum's "This Week in Technology."

The Internet is a uniquely modern institution—it has no buildings of its own, no owners, minimal governance. What the Internet is, more than anything else, is a set of ideas. At their core, those ideas are its network protocols. And the core of the core is a single one named, appropriately enough, the Internet Protocol.

Among other things, the Internet Protocol determines how to turn the Internet addresses that we type into a browser—gmail.com or ieee.org—into the numerical addresses, such as, which is Spectrum's IP address. Or one of Spectrum's IP addresses. And therein lies a problem. Too many organizations are using too many Internet addresses. And so we're running out of them.

So network engineers and system administrators are in the process of upgrading the Internet protocol, to what's called IPv6. This was done once before, in 1983. At that time, though, the number of computers on the network was in the thousands.

Imagine changing all the books in your house from the Dewey Decimal System to Library of Congress numbers. Now imagine doing that for every book owned by your local library. Now imagine doing it for every book in every library, every bookstore, and every household on earth. And yet we're doing it. Because sometime in the next few months, we really will run out of the old addresses. My guest today is Owen DeLong, who's in charge of IPv6 at Hurricane Electric. Hurricane Electric is a global Internet backbone provider that claims to have the largest IPv6 network in the world.

Owen, welcome to the podcast.

Owen DeLong: Thank you.

Steven Cherry: Owen, I'm going to ask you a question I get asked a lot and maybe you do too. The old Internet Protocol was known as IPv4 and the new one is IPv6. What happened to version 5?

Owen DeLong: Well, version 5 was actually assigned to an intermediary protocol that never really got widespread adoption and was later deprecated. So there was actually an IPv5; it's just that it never really saw the light of day, as is the case with many experiments.

Steven Cherry: The 4 in IPv4 refers to 4-byte addresses, meaning they're 32 bits long, meaning there's 2 to the 32 power of them for about 4 billion addresses. According to the latest stats there's just over 2 billion Internet users. How could we be running out of addresses?

Owen DeLong: Well, first of all the 4 in IPv4 actually refers to version 4. There were three versions of the Internet Protocol prior to IPv4 that also never really saw the light of day. However, you are correct that there are 4 octets—network engineers like to call them octets instead of bytes, because bytes might be different than 8 bits. Now, the 2 billion Internet users are potentially using 2 billion addresses for one device, right? They may be using more than one device on that address, but in a lot of cases each network address ideally goes to only one device, and when you start thinking about, well, you've got a cellphone, and you've got a laptop, and you've got a desktop and maybe an iPad. You start to see a situation where each individual person may have five devices or more that require IP addresses. Then you also have to account for addresses for things like infrastructure, the routers and the links that connect all these networks together, the Internet service providers, the domain name system infrastructure, and then of course there's all the Web servers and everything else that provides all this content on the Internet. So all of that added together is consuming the address space and I expect that the worldwide central pool of address space, the last of that will go out to the regional Internet registries probably in a week or two.

Steven Cherry: A week or two?

Owen DeLong: Yup.

Steven Cherry: Wow, our timing is impeccable I guess. As I understand it in the new world order there's going to be an IP address for everything. Every garment in a clothing store, every highway mileage marker, every tin can, maybe even every dollar bill. Is IPv6 going to provide enough?

Owen DeLong: Well, IPv6 provides a total of 340 undecillion unique addresses, and to put that in perspective, an undecillion is a 1 followed by thirty-six 0s. So this is 3.4 times 10 to the 38th addresses.

Steven Cherry: So, in other words that's a number with 38 zeros in it.

Owen DeLong: Yeah. To put this in perspective the square root of the number of IPv6 addresses is 18 quintillion. The square root.

Steven Cherry: [laughs] That's great. Owen, Manhattan where our offices at Spectrum are, is built on a grid and it has number-based addresses. You know, if we changed all of those addresses, it would be quite a pain, but that's because we'd have to actually physically change all the street signs and doors and awnings and people's business cards. You know, we would still do it; it would take a few months and then it would be done. IPv6 has been taking years and years and it's just software. I mean, is it really that hard, or is this just like one of those construction projects where they close off a road and they don't do anything for a few years?

Owen DeLong: Well, it's a lot like the construction project you described except nobody's closed off the road yet. The situation is more one of, if I came to Manhattan and I said, "Hey, look, the current numbering system in Manhattan probably isn't going to support the buildings that you're likely to build in 10 years. How about we renumber everybody's addresses today?" People in Manhattan would sort of look at me and go, like, "Well, how about we renumber in 20 years when it matters?" And that's a lot of what's happened on the Internet is nobody's really wanted to rush out and put all this effort in until they see a real need to do it on a more urgent basis. Unfortunately, what that means is that the transition is not going to go as smoothly as we hoped when we were trying to get everybody to change earlier but the transition is happening and, you know, some organizations are further along with that than others. Hurricane Electric is fully deployed in dual stack and completely ready to serve everybody's needs going forward. Other providers are going to be playing catch-up. There are other providers that are fully v6 capable as well.

Steven Cherry: And dual stack means that you're running both protocols, the old one and the new one?

Owen DeLong: Correct.

Steven Cherry: How hard is that? Is that a real problem for networks?

Owen DeLong: It depends on your network. But in most cases for an infrastructure network providing IP transit, it's fairly easy. For a lot of content providers it won't be too complicated, but there are some things that they're going to need to keep in mind, depending on the way their particular site is implemented. Where it's going to be hardest is going to be the enterprise networks, because they've become so ingrained with the technology known as network address translation and, you know, certain ways of doing things that just don't scale to an IPv6 world.

Steven Cherry: So what are the practical consequences of IPv6 for ordinary Internet users, for, you know, my mom with her Windows laptop for example?

Owen DeLong: Well, ideally, if we the service providers and the other people in the industry—the content providers, etc.—all do our jobs right and have all the stuff ready to go by the time your mom is forced to move to IPv6, she doesn't even notice it. It doesn't make any difference to her per se. The difference it will make over time is because IPv6 restores what's called the "end to end model" the ability for any arbitrary host "A" on the network to offer services to or connect to services on any other arbitrary host "B," assuming that it's permitted by policy at both ends, there's a lot of applications and a lot of things we can do with that that have not been available in the IPv4 world due to the widespread use of network address translation, and more specifically, overloaded network addresses where we're putting more than one device behind a single public address. That situation is unfortunately likely to get worse before it gets better, because the reality is we didn't manage to get our jobs done well enough on time for her not to notice this transition. She's probably going to go through a period where she's behind what we're calling NAT444, where not only does she have the NAT gateway that she's used to in her home, but the address on the outside of that will no longer be a public address; it will become an intermediary address that then goes through another layer of NAT at the carrier, and unfortunately there's going to be some problems with that. There are some applications that will not work through that. A lot of the instant messaging stuff, a lot of the voice over IP stuff, and a lot of other things, a lot of gaming systems and such which, you know, she may not be using but a lot of people are, are going to have problems with that environment.

Steven Cherry: So, let's just recap here, the network address translation, or NAT, that's the system whereby you get a single address, say in your household, and all the devices inside that household: the iPad, me when I come over with my laptop for the afternoon, they all kind of share that one address and that's generally done by her Wi-Fi router, so that's one level of the problem. And then the other level of the problem is that as that one address that she has that she gets from, say, her cable broadband provider, it may itself be a network address translation address coming from some cable provider's network. Is that right?

Owen DeLong: Correct.

Steven Cherry: Okay. So, just to recap for my hapless mother with her Windows laptop and her Wi-Fi router, she's not going to have to do anything different but some of her software won't work unless it's upgraded?

Owen DeLong: Well, she's going to need to upgrade some of her software, she's probably going to have to replace her wireless gateway at some point, and possibly her cable modem or DSL modem, depending on, you know, the particular devices she's got and how they're provided. And then of course there's probably other devices in her home which may not be ready for IPv6. For example one of the places where we're really seeing a problem is, the consumer electronics industry has not caught on to this. TiVo doesn't support IPv6 yet. None of the PlayStations or Xboxes or anything like that have any IPv6 support available yet. I've got this Yamaha amplifier that, you know, does Internet radio and has an IP connection on the back and it doesn't support IPv6. And so there's a lot of changes coming and depending on how much gear you've got that attaches to the Internet, and how good the vendors that you got the gear from are about supporting IPv6 going forward, you may or may not have some problems with that.

Steven Cherry: Very good. And the problems that may arise may arise soon because, as you say, we really, really, really are running out of addresses and so in the next weeks or months, more and more providers are going to have to switch to IPv6. Is that right?

Owen DeLong: It's going to be months on the provider's side in terms of the "have to switch." The sooner providers start switching, the easier the transition process is going to go, because it's always easier to plan something when you've got some time to do it and do it in a coordinated manner than it is to go, "Uh-oh, things are breaking. Now we've got to fix them somehow" and doing it in a panicked rush. And this is a pretty major change in some ways, so it really is best if it can be planned and done in a controlled manner.

Steven Cherry: So, finally getting back to my hapless mother and her laptop, when will she actually start feeling some pain from this?

Owen DeLong: She could start feeling some pain from this as early as June. It may take until September or December depending on where she is and who her provider is and how this conversion goes in some other parts of the Internet.

Steven Cherry: And the way she's likely to feel it is some device, maybe like a TiVo or something, just no longer works?

Owen DeLong: Well the first pain she's going to feel is when her ISP comes to her and says, "You need to replace some of your equipment so that we can connect you over IPv6." The next pain she'll feel is going to be quite a bit later, when she starts running into the situation where service providers start turning off IPv4 and her v4-only devices can no longer talk to the global Internet…but that could be years from now.

Steven Cherry: So the first step is, sometime in, maybe, in the next six months or so her cable or DSL provider is going to say, "You need a new cable modem or DSL modem."

Owen DeLong: Yup.

Steven Cherry: Very good. Well, thanks so much. We appreciate your time with us.

Owen DeLong: Anytime. I enjoyed it.

Steven Cherry: I've been speaking with Owen DeLong of Hurricane Electric a global Internet backbone provider about the world running out of Internet addresses, and what the Internet engineers are doing about it. For IEEE Spectrum's "This Week In Technology," I'm Steven Cherry.

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