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What will IPv4 address exhaustion mean for your network?

Will IPv4 address exhaustion affect your enterprise network? What will happen when IPv4 address space runs out in two years, and what is accelerating IPv4 address depletion? Is a transition to IPv6 really necessary? Find out the answers to these questions in this Q&A with IPv6 expert Scott Hogg.

IPv6 security book cover Will IPv4 address exhaustion affect your enterprise network? What will happen when IPv4 address space runs out in two years, and what is accelerating IPv4 address depletion? Is a transition to IPv6 really necessary? Find out the answers to these questions in this Q&A with IPv6 expert Scott Hogg. Scott Hogg is author of IPv6 Security and chairman of the Rocky Mountain IPv6 Task Force, a regional chapter of the North American IPv6 Task Force, which is part of the global IPv6 forum. He recently organized the successful RMIPv6 Summit.

Some IT experts I've spoken with say enterprises shouldn't worry about IPv6 right now. Is there a reason to transition to IPv6 now? And if not, why haven't people come to terms with IPv4 address exhaustion?

Scott Hogg: The average user, or administrator for that matter, does not see the global problems related to IPv4 address exhaustion. But we're running out of address space, just [as] we could run out of phone numbers, potentially. The way IPv4 addresses have been allocated, there are only about 6% left.

I think the people you talked to may be in denial about this evolution. It's not immediate. It's not something that's going to cause you to stop working today, or impede your communication today. But it's a future thing, an evolution, and we should all be knowledgeable about this and be aware, then start the planning process for the IPv6 migration. Because if you wait until two years from now to start your planning, it's going to take you a year or two to learn about the protocol, start to develop some designs of how you're going to help your organization add IPv6 to your network, then start to slowly transition over the next five to 10 years. If you wait until the last minute to start your planning and budgeting to give yourself time and money to make this transition, it's going to be too late for your organization; you're going to be behind the curve.

I think a lot of people are in denial about understanding this process, and they don't know that eventually the Internet will stop working as a result of address depletion.

What is accelerating IPv4 address depletion? Does virtualization play a role in less address space?

Hogg: I think virtualization could be accelerating IPv4 address depletion because the hosts are consuming lots of addresses. One physical host could have many different IP addresses on it.

What's really consuming more IPv4 addresses are mobile devices. There are millions of mobile devices out there—iPhones, Android phones, smart devices. They could communicate with IPv6, but they communicate with IPv4 today, and they consume lots of [IPv4] addresses. Wireless mobile providers selling lots of advanced smartphones are running out of addresses, and you're going to hear a lot from carriers about 4G networks this year. The carriers are building 4G networks, and one of the drivers is to help them migrate to IPv6. That is one of the requirements of the 4G network and 4G protocols. The phone will communicate IPv6 behind the scenes, and end users won't know they're communicating with IPv6. But it could be used as a strategy to help wireless carriers give addresses to the phones, while still enabling communication.

Broadband access providers, DSL, cable, technology for broadband access—these are consuming a lot of addresses as well. All the network devices, the cable and DSL modems need to have IPv4 addresses to be [manageable]. If carriers could transition that infrastructure to IPv6 and manage those devices with IPv6, that would free up a lot more addresses for new subscribers.

Wherever a service provider allocates lots of addresses to subscribers for any type of access, whether wireless or wired, a lot of addresses are consumed in that process. Those companies are actively looking at how they can use IPv6 to alleviate that and still provide good connectivity to customers, give the customers options for communicating with IPv4 and IPV6, and free up addresses that routers can allocate to customers—to continue to grow their business. 

What will happen when the world runs out of IPv4 address space? Will an IPv4 address exhaustion affect your enterprise network?

Hogg: The world is not going to come to an end. Even if all the IPv4 address space is allocated, the Internet will continue to function. But what will happen over time—time frames could be two to five years—[is that] there will be a population on the Internet that can get only IPv6 addresses because there are no IPv4 addresses left.

For example, if someone comes out with [an] innovation that requires IP addresses to connect to the Internet, it won't be able to get IPv4 addresses; it will only be able to get IPv6 addresses. Therefore, it won't be able to talk to anything on the IPv4 Internet.

So as long as you're OK with remaining on IPv4, you'll only be able to communicate with people who have IPv4. You won't be able to communicate with people who have IPv6. If you're OK with [for example] speaking Latin for 1,000 years, that's OK. You can continue to speak Latin, but you'll only be able to speak Latin to people who know Latin.

Eventually, the rest of the world will migrate [to IPv6], and you'll be left on an island. That's what's going to happen. There is no alternative to IPv6. It is an inevitability that we migrate. It's the only thing available. The Internet Engineering Task Force (IETF) has put 17 years of research and development into IPv6, the next generation Internet; there is no other solution available. 

So IPv6 is not backwards compatible with IPv4? Could you give an example of what an IPv4 user might see when trying to access an IPv6 website?

Hogg: If you're on an IPv4-only network device and you tried to open up your Web browser to go to a website that only has a domain name system (DNS) entry that was a AAAA record that resolved to an IPV6 address—your Web browser will say "page not found" and it will just be unable to communicate with that Web server…. If it was an IPv6-only Web server and an IPv4-only host and there's no transition mechanism in place, they wouldn't be able to communicate with each other.

Read part 2 of this Q&A to understand who must start an IPv6 transition, or for more on this topic, read what the IANA's IPv4 depletion means for enterprises. 

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