The Internet Society estimates that a minority of Internet users - 0.05% - will experience slowdowns or have trouble connecting to participating Web sites during the trial because of misconfigured or misbehaving network equipment, primarily in their home networks.
"There may be some individual hiccups for some small access providers or users, but IPv6 is not an experimental technology," Daigle says. "I do believe it will work."
The day-long IPv6 trial is a critical development for content providers such as Google and Facebook, which until now have been supporting IPv6 at separate, dedicated Web addresses rather than on their main traffic-heavy Web sites. Google, for example, says it will enable IPv6 on its main Web sites - including www.google.com and www.youtube.com - for World IPv6 Day.
The event is also a big deal for Yahoo, which has been reluctant to support IPv6 because of concerns about using a DNS whitelisting approach like Google's, which provides IPv6 content only to users with known end-to-end IPv6 connectivity.
"Participating in World IPv6 Day will allow us to obtain real-life data that we can use to ensure a seamless user experience as we transition to IPv6," said Adam Bechtel, vice president of Yahoo's Infrastructure Group, in a statement. "We welcome this opportunity to collaborate with the technical community and provide leadership in addressing the scaling challenges facing the Internet."
In order to participate in "World IPv6 Day," these companies must adopt a dual-stack deployment, which allows native IPv6 traffic to run alongside IPv4 traffic without shortcuts like whitelisting.
"These organizations have committed to full-on IPv6 access, with no whitelists or other [workarounds]," Daigle says. "Everybody who has an IPv6 address will get in their sites on that day.''
The Internet Society initiative comes on the heels of a move by the U.S. military to nudge its IT vendors to support IPv6 on their public facing Web sites.
The Office of Management and Budget went a step further in September, when it mandated federal agencies to support IPv6 in dual-stack mode on their public facing Web sites by fall of 2012.
The Internet Society is hoping that its World IPv6 Day will have a similar ripple effect, prompting content providers, ISPs, hardware manufacturers and operating system suppliers to transition to IPv6 as soon as possible.