IPv4 addresses: They are almost gone

This past Tuesday, the organization responsible for managing IPv4's unallocated-address pool announced that addresses are almost gone. What does that mean?

The Number Resource Organization (NRO) represents the five Regional Internet Registries (RIRs) and is responsible for the unused IPv4 addresses as explained in their charter:

"The NRO exists to protect the unallocated Number Resource pool, to promote and protect the bottom-up policy development process, and to act as a focal point for Internet community input into the RIR system."

That's great, but why tell me, you may ask. Well, they feel the IPv4 address space has reached a critical juncture. That is, the number of remaining IPv4 addresses is less than 10 percent. If you are a clock watcher, you can keep track of the estimated days left before they are all gone at the Internet Society Web site.

What's 10 percent?

The IPv4 addressing scheme consists of a 32-bit address space. According to RIPE that means IPv4 address space is 32-bits (232) in size and contains 4,294,967,296 addresses. At the time of this article, my iPhone app showed that 402,291,729 addresses (9.4 percent) remained. According to the app's count-down meter, all the addresses will be gone in 593 days.

Is it a problem?

I have written extensively (even made some podcasts with Joe Klein) about IPv6. Yet, I never really dwelled on this topic. It appears time to start. Like anything else, there are two sides: those that believe it is a problem and those that don't. Let's look at both viewpoints before deciding who's right.

Will run out

NRO raised the alarm, so they definitely feel it's a problem. Here is what Axel Pawlik, Chairman of the NRO says:

"With less than 10 percent of the entire IPv4 address range still available for allocation to RIRs, it is vital that the Internet community take considered and determined action to ensure the global adoption of IPv6.

The limited IPv4 addresses will not allow us enough resources to achieve the ambitions we all hold for global Internet access. The deployment of IPv6 is a key infrastructure development that will enable the network to support the billions of people and devices that will connect in the coming years."

According to my research, most agree with Pawlik. The IPv4 address space is rapidly depleting

Not running out

The people I've talked to, who feel we are not running out of addresses, tend to agree with what Steve Gibson talked about in this podcast. His argument is that NAT routing reduces the pressure to move to IPv6 and will continue to do so. So IPv4 addresses will not run out and the timeline for moving to IPv6 is unclear.

Since the podcast was two years ago. I tried (unsuccessfully) contacting Steve Gibson, to see if he still feels the same. Regardless, many businesses and organizations are hoping he is right. Switching everything to IPv6 is expensive and there is a steep learning curve.

Compare to IPv6

The replacement addressing system, IPv6, uses a 128-bit address space. With RIPE's help again, the IPv6 address space is 128-bits (2128) in size, containing 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses. That seems like enough.

Final thoughts

Experts have differing opinions about what to expect when available IPv4 addresses become fewer and fewer. Some feel NAT will become commonplace at ISPs, large and small. Others say this is a wake-up call and IPv6 will gain momentum. Either way, it will be interesting.

My real concern is for the people who this directly affects. You know, the ones that have to make it work. As I mentioned earlier, IPv6 requires some effort to learn. For help in that regard, check out Charles Kozierok's Web site. It helped me get up to speed.