We've known for decades that the available pool of IPv4 address was eventually going to dry up, but despite numerous warnings usage of its successor IPv6 is still minimal. Why haven't we migrated yet? Geoff Huston, chief scientist for regional internet registry APNIC, suggests that the answer is that carriers are too cheap to make the switch and are happy to rely on network address translation (NAT) systems instead.
IPv6 picture from Shutterstock
In a presentation at Linux.conf.au in Canberra yesterday, Huston pointed out that despite the fact that allocation of IPv4 addresses is now effectively frozen, uptake of IPv6 has been very slow. "At the moment, there's very little IPv6 out there," he said, citing measurements that suggest active usage below one per cent. "Most of the world is capable of running IPv6 but doesn't.
Rather than rebuilding their systems, carriers have favoured using NAT instead, which effectively allows multiple devices to use the same IP address, with the NAT equipment determining which address needs to go where. "Almost everyone now in the mobile part of the world uses carrier-grade NATs and increasingly this is happening in the wired world as well," Huston said.
It's a messy solution and one with several limitations: you can't readily access HTTPS content, for instance. However, it's much cheaper than acquiring new hardware. Huston estimates the cost at $40 per user per year, and that figure continues to drop.
So what happens if you want to build a new data centre and need a fresh block of IP addresses for that purpose? Effectively, you have four choices. APNIC might be generous offer you a small block of 1024 IPv4 addresses from its remaining pool, but that's not guaranteed and it may not be sufficient. You can try and build an all-IPv6 centre, but many equipment manufacturers haven't made the switch yet. As Huston puts it: "Go to a vendor and say you want dual stack equipment and they will laugh at you."
You can try and buy IP addresses from existing owners, but despite predictions of price gouging Huston says the secondary market remains relatively undeveloped so far: "It's not a market, it's just a bunch of people playing around."
The biggest pools of addresses are now owned by large telecommunication companies. "There are no more small-scale ISPs any more," Huston observed. "This industry has agglomerated like crazy. Finally, you can use NAT, which appears to now be the default choice.
Huston noted that while IP technologies have been adopted by carriers, that didn't happen without a struggle. "When you look at the Internet, you in some ways see a story that exists despite the telephone companies."
The challenge now is in updating the network hardware. Modern operating systems all support IPv6, as do most newer phones. "Considering how fast we cycle through technology, most of the stuff out there talks IPv6," Huston said. However, that doesn't help if the equipment those devices connect to doesn't use the newer protocol.
In Australia, the only ISP offering IPv6 by default for new connections is Internode, and none of the mobile carriers offer it. "That's why the numbers are so shit. None of the providers in the last mile are willing to take the punt," Huston said.
End users might not care how their IP addresses are assigned, but an internet based largely on NAT systems would completely eliminate network neutrality, Huston suggested. "A carrier-grade NAT is like a toolbox. The access provider has visibility to the traffic, and the rationing model changes."
"Once we've exhausted IPv4 addresses there's no such thing as end-to-end anymore All of your traffic is pulled apart and sometimes the content is changed. All of a sudden, openness doesn't exist any more. This whole idea of permission-less networking is over if the network is ridden with middleware and with folks whose economic incentive is to restrict the edge because they want their money back."
For Huston, the biggest issue is that the resistance to IPv6 might signal a move away from the open standards-based world that the internet has heralded, returning us to the state of technology three decades ago. "Back then, everything was proprietary. It was a closed world. We never see much of that any more, apart from the iPhone which is a resurgence of the same thing. This is a world which is dominated by openness, but how fragile is this? Will it last?"
"What we've really done is shut down the last 10 years of fascinating, mind-boggling marvellous innovation and replaced it with crap. It's time to think about this and choose very carefully."
Lifehacker's World Of Servers sees me travelling to conferences around Australia and around the globe in search of fresh insights into how server and infrastructure deployment is changing in the cloud era. This week, I'm in Canberra for Linux.conf.au, paying particular attention to the systems administration mini-conference and sessions on virtualisation and best practice.