Reflecting on World IPv6 Day - The Internet Protocol Journal, Volume 14, No. 2

Phil Roberts, ISOC

On June 8, 2011, many websites around the world made their main webpage reachable over IPv6 for 24 hours, and many of those that did this left their sites IPv6-accessible afterward.

Major worldwide websites enabled IPv6 on their main page. Google enabled not only its main website but also YouTube and Blogger. Facebook and Yahoo! both enabled their main webpages as well. These websites are the five most visited websites in the world according to Alexa rankings. Other major worldwide websites that enabled IPv6 include Yahoo! Japan, Bing, Microsoft, BBC, CNN, and AOL.

Important local websites in countries around the world also joined in. In South Korea both Naver and Daum (the first and fourth most visited sites in South Korea according to Alexa) joined the event. In the Czech Republic four of the top 25 local websites joined. There were also major sites from Brazil, Portugal, and Indonesia.


Enabling IPv6 in this way served numerous purposes:

  • Network operators clearly saw that content is going to be available on IPv6. Although the major websites may not be quite there yet, it is clear that they are seriously moving in that direction.
  • The industry worked to improve problems with IPv6 connectivity. Some immediate improvement resulted, and more fixes are underway to further improve IPv6 connectivity.
  • Setting a public date created a deadline that accelerated deployment for many of the organizations that contacted us.
  • It was important to be compared with Google, Facebook, and Yahoo!. Participants in this experiment wanted to be seen doing the same thing as the industry giants.
  • This event was a clear example of how the Internet industry can work together to deploy technology that is for the good of the Internet, without intervention from outside entities. The multistakeholder model of Internet development continues to function well.

More than 1000 organizations contacted the Internet Society. Many of these organizations had already permanently enabled IPv6. Of the 430 or so websites the Internet Society monitored on the day, roughly two-thirds have continued to provide IPv6 access after the day.

In addition, major hosting companies enabled IPv6 for large numbers of domains, including Domain Factory, which, as a result of participating in World IPv6 Day, has made IPv6 "on by default" for all of its more than 800,000 domains. Another hosting company, Stratos, left IPv6 on after June 8 for its more than 4 million domains.

RIPE Labs did extensive measurements of IPv6 leading up to, on, and after the day, and it has published results indicating an increase in IPv6 traffic on the day—and an overall increase in IPv6 traffic also after the day.

Figure 3: MPLS VPN "Customer Carrier" Network Connected Across NGN "Backbone Carrier"


[1] Phil Roberts, "World IPv6 Day," The Internet Protocol Journal, Volume 14, No. 1, March 2011.

[2] RIPE Labs, "Measuring World IPv6 Day—Long-Term Effects,"

[3] RIPE Labs, "Measuring World IPv6 Day—Some Glitches And Lessons Learned,"

[4] RIPE Labs, "Measuring World IPv6 Day—First Impressions,"

PHIL ROBERTS joined the Internet Society (ISOC) in 2008. Prior to that he spent several years with Motorola in research and product development, all in the area of mobile broadband systems. He has been active in the IETF for more than a decade. He can be reached at: