The much-hyped World IPv6 Launch Day event on Wednesday resulted in a rise in IPv6 traffic -- including Web and email -- to a new peak as expected. But ISPs said the bigger story was the steady increase in IPv6 traffic that occurred in the months leading up to the event, which they anticipate will continue for the rest of 2012.
Coordinated by the Internet Society, World IPv6 Launch Day was a kick-off event for more than 50 access network providers such as AT&T, Comcast and Time Warner Cable and 3,000 websites -- including Facebook, Google, Yahoo and Bing -- to begin permanently supporting IPv6 for their customers.
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Several carriers, including Comcast and Hurricane Electric, reported that IPv6 traffic rose between 20% and 25% on their networks during the first few hours of World IPv6 Launch Day.
"Right after the initial launch, we saw a 20% to 25% increase in IPv6 traffic, which was expected," said John Brzozowski, distinguished engineer and chief architect for IPv6 at Comcast, which has 1.5% of its residential subscribers using IPv6 at this time. "We're not getting any trouble reports from the field. To us that means that our customers are happily going about their business using their Internet service disruption-free."
The event was a success for Comcast, which has been working on IPv6 for seven years and has the most aggressive deployment plan for next-gen Internet services among U.S. broadband providers. Comcast has enabled IPv6 across one-third of its subscriber network as well as providing IPv6 on its own websites, such as www.comcast.net and xfinitity.comcast.net.
"We're seeing over 1% of the traffic to our own content coming over IPv6," Brzozowski said. "The launch of IPv6 on the broadband side of the house is now resulting in over 1% of our traffic to our own content being IPv6. That's a pretty good measure for us of IPv6 adoption and usage."
IPv6 is an upgrade to the Internet's main communications protocol, known as IPv4. IPv6 is needed because IPv4 is running out of addresses. However, IPv6 is not backward-compatible with IPv4. So network operators must run the two protocols side-by-side in what's called dual-stack mode or translate between them, which adds cost and latency to their operations. Because of these complications, IPv6 has suffered from a slow adoption curve. That's why Internet policymakers are promoting IPv6 through events such as World IPv6 Launch Day.
In addition to driving up IPv6-based Web traffic, World IPv6 Launch Day also saw a bump in IPv6-based email, with Google opening up Gmail to IPv6 and Comcast allowing some customers to send and receive email over it, too.
Comcast enabled its email infrastructure to support IPv6 in conjunction with Cloudmark, which reported that the first IPv6 email that Comcast received was spam. Cloudmark is pitching to ISPs a new way of filtering spam for IPv6 that involves tracking legitimate email senders rather than blacklisting spammers.
"Yes, our first IPv6 message was spam," Brzozowski said. "Deep down, I was hoping that it wouldn't be. Sadly, we had to wait a little while for a bona fide message that came over IPv6. ... We've taken our first step with IPv6-enabled mail with every intention that we will expand it over time."
Despite these increases over the last 24 hours, IPv6 represents a tiny share of overall Internet traffic.
Arbor Networks, which is monitoring IPv6 traffic across 15 service provider networks for World IPv6 Launch Day, said native IPv6 traffic rose to 0.1% of all Internet traffic in the first few hours of the event, which represented a 20% increase. Arbor said that IPv6 traffic has almost doubled in the year leading up to World IPv6 Launch Day.
"World IPv6 Launch Day is a starting point for providers to offer IPv6 services permanently going forward," explained Scott Iekel-Johnson, product manager for Arbor Networks. "The long-term trend is slow-and-steady increases since last year with native IPv6 traffic, which is what we want to see. The reason we didn't see a dramatic increase today is that the increase has been happening throughout the last week, the last month, the last year. That's why today is a relatively small bump."
Arbor did see a bigger bump for email, with 2.5% of all email going over IPv6 on Wednesday.
"Some providers are migrating their real infrastructure -- including email -- to IPv6, and that's a good sign," Iekel-Johnson said. "But until regular people are using IPv6, we can't claim success. Clearly we still have a way to go, but we are moving in a successful direction."
Michael Bailey, assistant research scientist at the University of Michigan, said his National Science Foundation-funded research also shows a positive long-term adoption trend for IPv6.
"The long-term trend has been a slow-and-steady increase in the amount of IPv6 traffic, the amount of name servers that are addressable via IPv6 and the amount of DNS resolvers that are querying IPv6," Bailey said. "We see similar patterns with IPv6 allocations from the regional registrars and the routing data and naming data."
Bailey called World IPv6 Launch Day a success in terms of proving that IPv6 is ready for deployment, but he warned that "there is a long road before IPv6 is in parity with IPv4."
Nonetheless, ISPs are optimistic that IPv6 traffic will continue to rise during the rest of 2012.
Hurricane Electric, a Fremont, Calif., ISP that claims the world's most interconnected IPv6 backbone, said its IPv6 traffic volumes rose more than fivefold in the week leading up to World IPv6 Launch Day.
"I think we've begun to see the knee in the curve of IPv6 adoption," said Owen DeLong, IPv6 evangelist and director of professional services at Hurricane Electric. "I think we are going to normalize, where we are going to see 1% to 2% growth per day from now on."
DeLong pointed out several statistics that he believes will drive IPv6 traffic growth through the end of the year and beyond:
-- 85% of the Internet's top-level domains such as .com, .net and .org support IPv6.
-- 3.6 million registered domains have the AAAA records needed for IPv6 connectivity.
-- 13% of networks are running IPv6 (as measured by the Autonomous System Numbers in the global routing table).
He also said that the depletion of unassigned IPv4 addresses in Europe, which is expected this summer, could create a spike in IPv6 activity, as might the U.S. federal government's mandate for agencies to support IPv6 on their websites by Sept. 30, 2012.
"I think we'll have a few big publicity events going forward that will drive a few amps of IPv6 traffic, but overall I think we're going to see continued, steady growth," DeLong added.