A study this week has revealed just how slow is the rate of adoption for IPv6, the next version of the Internet's main communications protocol, and some experts say black markets where companies trade unused IP addresses may be only a few years away.
The report, from Arbor Networks, claims to be the most comprehensive study of IPv6 use to date. It includes few surprises for those who follow the area closely, but the results provide a sobering measure of how just slowly the technology has been adopted.
"At its peak, IPv6 represented less than one hundredth of 1 percent of Internet traffic" over the past year, Arbor Networks' Craig Labovitz wrote in a summary of the findings, adding wryly: "This is somewhat equivalent to the allowed parts of contaminants in drinking water."
Arbor said it put together the study over the past year, working with the University of Michigan and almost 100 ISPs and content providers, including a quarter of the biggest ISPs in the U.S. and Europe. It used commercial traffic probes to monitor about 2,400 peering and backbone routers and 278,000 customer and peering interfaces.
"We believe this is the largest study of IPv6 and Internet traffic in general to date (by several orders of magnitude)," Labovitz wrote.
IPv6 is the successor to the current version of the Internet's underlying protocol, IPv4. Its adoption is important because IPv4 can support only about 4 billion IP addresses and they are fast running out, while IPv6 will be able to support many trillions more (2 to the 128th power). It also offers advantages in security and network management.
Some experts say the supply of IPv4 addresses will run out in the next few years. Matthew Ford, a principal researcher with BT's Networks Research Centre in the United Kingdom, operates a Web site that counts down the days until IPv4 addresses are used up. As of Tuesday, it predicts that the central registry of addresses will be exhausted in 904 days.
Few people expect disaster to ensue. The Arbor report notes that IPv6 adoption is growing, albeit at a slow pace. Since July last year IPv6 traffic has grown by nearly a factor of five, to an average of 100Mbps per day. "Though not a landslide of adoption, it is still something," the report says.
What's more, there are already creative ways to get around the shortages, like using network address translators, or NATs, which essentially allow many computers to share the same IP address. There are also many addresses that were allocated to organizations and are not being used.
That's why some, including Labovitz, expect companies to trade unused addresses with each other, on a black market if the activity isn't officially sanctioned. "I think an IPv4 market is inevitable," he wrote.
BT's Ford said he wasn't surprised by the results, but he cautioned that the figures may not be completely accurate. Arbor acknowledged that it did not distinguish between native and tunneled IPv6 use, he noted, and the figures may also be skewed toward what's happening in the U.S., where many of Arbor Networks' customers are.
"The U.S. has historically been quite sluggish, and most IPv6 research and implementation has been in Europe and Asia," said Ford, who previously chaired the IPv6 Cluster of the European Commission.
Nevertheless, the adoption has clearly been slow and the study should be a further wake-up call that widespread adoption of IPv6 needs to begin quickly, Ford said.
"Two or three years ago you could make the argument that [the exhaustion of IPv4 addresses] is far enough away that we don't need to make the investment," he said. But given that widespread adoption will take about two years to implement, "now is the time for large ISPs and content providers to begin their migration."
Arbor Networks said money is the main reason for the delay. The U.S. Department of Commerce has estimated it will cost $25 billion for ISPs to upgrade to native IPv6. "This massive expense comes without the lure of additional revenue, since IPv6 offers diminishingly few incentives nor new competitive features to attract or upsell customers," Labovitz wrote.
Ford said enterprises may be among the earlier adopters because they can suffer the most from having to use IPv4.
"They can suffer problems through corporate mergers, because both parties might be using the same address space, or they find they have a lot of network address translators, which can make it challenging to deploy new applications. IPv6 helps both those problems," he said.
In addition, deploying IPv6 within the enterprise can be easier than it is for ISPs, which have to make more connections to outside networks.
"While it is easy to poke fun at predictions of the 'Imminent Collapse of the Internet', the eventual exhaustion of IPv4 allocations is real," the Arbor report states. "We need to do something. And IPv6 is our best bet."