It's been billed by its organisers as the most important day for the future of the Internet, but so far World IPv6 Day has probably served to confirm what the industry already knows about the 128-bit protocol on which the 21st century digital society will be built; there is not a lot of it about.
With engineers at many of the event's big brand participants including Google, Facebook, Yahoo and Cisco poring over traffic graphs, initial monitoring by Internet security company Arbor Networks suggested that on June 8 Internet Protocol 6 will at best account for 0.02 percent of global Internet traffic at any point during the day.
Over at infrastructure giant Akamai the numbers were equally underwhelming, showing IPv6 traffic on a marked uptick as the day kicked off, but from very low levels. Google, a giant whose measurements probably count more than any other single entity, has been slightly more optimistic, calculating that total IPv6 traffic through its servers at 0.3 percent in the period leading up to Wednesday's test.
This doesn't sound like a lot of traffic, because it isn't. Most OSes and applications such as browsers and search engines can resolve IPv6 addresses, but the routers that actually deliver the packets to the correct addresses generally can't. World IPv6 Day's simplest objective was probably to point this out to the industry, as an incentive to spur further investment.
The real success of the day will depend on more than traffic volumes however, especially measuring the volume of "native" IPv6 traffic detected, which gives a hint at how the protocol is being deployed. According to Arbor Networks, only around 10 percent of IPv6 on June 8 has so far been sent in native form, with the rest tunnelled or encapsulated within IPv4 to ensure compatibility.
This is much the same as it was when the company last looked during an IPv6 test day in April, and reinforces that end-to-end IPv6 communication is still not making much headway despite warnings over the dwindling pile of IPv4 addresses left to deploy.
The encapsulation might also explain why, according to the European Internet registry, Réseaux IP Européens Network Coordination Centre (RIPE NCC), latency for IPv6 packets on June 8 has been about 10 percent higher than for IPv4. IPv6 packets are not only much rarer than IPv4, they appear to travel more slowly too.
Despite its apparent twilight existence, many in the industry believe that the IPv6 numbers are beside the point. The significance of the day was to build confidence.
"The day has shown that if you turn IPv6 on the world will not collapse," said Robert Kisteleki, R&D manager for RIPE NCC, who has judged the day a proof of concept success. "Virtually all users will still be able to connect."
In Kisteleki's view "the critical points are the 'eyeball' networks", large Content Delivery Networks (CDNs) that host the content Internet valued by ordinary Internet users. "Many of the CDNs may just decide to leave IPv6 turned on. If that happens we will not need another IPv6 Day," he said.
Individual users can run the Internet Society's test suite of IPv6 readiness to check their own ability to reach IPv6 sites. Most users will fail on some of the tests that measure an ISP's ability to handle IPv6 requests, especially in relation to native DNS requests.
A less ambitious test is available from RIPE NCC's site, which measures whether a user's PC can reach what are called "dual-stacked" IPv4/IPv6 sites from a list of large companies participating in the test. Everyone connecting through a mainstream ISP should pass this test.
The lessons learned from Wednesday's test, if any, will be offered to the industry at next week's IPv6 World Congress.