It has been several weeks since World IPv6 Launch took place on June 6th. However, it will remain the single biggest event in the development of IPv6 for many years. World IPv6 Launch was heavily promoted, but in the end, no one really noticed, which I suppose is a good thing. Network engineers, like airline pilots, never want to be mentioned on the front page of news papers. So what is the next milestone on the horizon for IPv6?

What is World IPv6 Launch?

World IPv6 Launch was the permanent enablement of IPv6 by many significant Internet companies. The Internet Society (ISOC) was the coordinator of this June 6th event, similarly to how they facilitated last year's World IPv6 Day 24-hour test. Today if you point your web browser to Google, Facebook, YouTube, Yahoo!, Wikipedia, Bing or many other sites, and you have IPv6-Internet access, then you will get there using IPv6.

World IPv6 Launch was also supported by several large ISPs who facilitated getting over 1% of their total subscriber base IPv6 Internet access.

World IPv6 Launch also benefited from several leading network equipment manufacturers offering IPv6-capable CPE to end-users with IPv6 Internet connectivity.

Without the cooperation of this triumvirate of communities to break the IPv6 deployment logjam, IPv6 would still be languishing with very low traffic volumes.

What Happened?

Years ago, many content providers were naturally hesitant to implement IPv6 Internet connectivity and offer up both a DNS A-record and AAAA-record for their money-making web sites. There was significant concern over a small percentage of broken IPv6 Internet connectivity and how many operating systems and web browsers would prefer IPv6, but not quickly fall back to using IPv4 if there were problems with IPv6 connectivity. However, due to the substantial efforts of many software companies and the development of the Happy Eyeballs concept and RFC, the "IPv6 Brokenness" on World IPv6 Day seemed to be much less than the industry anticipated. The confidence in IPv6 robustness grew and World IPv6 Launch prompted content providers to be more aggressive about their IPv6 deployments.

When IPv6 was first developed, the IETF realized how important it was to develop transition technologies to ease the burden of migrating from IPv4 to IPv6. It was firmly understood that there was not going to be a single "flag day" where the entire Internet would hot-cut to IPv6. The industry developed many tunneling and translation strategies, but the dual-stack approach was always the preferred transition technique. In the end, it turned out that it took a flag-day event like World IPv6 Launch to demonstrate that dual-protocol is the best migration strategy.

Now that the dust has settled from the build-up to World IPv6 Launch, it appears that no one noticed. Unlike Y2K, World IPv6 Launch didn't make it on the evening news and that is a testament to good network and systems engineering. I have been thinking that someday IPv6 will be on the NBC Nightly News, but it may be some time before anyone will recognize the efforts of the people behind the curtain.

Growth of IPv6 Traffic

The amounts of IPv6 traffic have been growing slowly and steadily over the past 5 years, but are still quite small compared to IPv4. Over the past year, the IPv6 traffic volumes have been building as more organizations deployed IPv6 and more web pages started serving up their content over IPv6. On the first day of World IPv6 Launch, IPv6 Internet traffic immediately increased 20% to 25% more than normal levels. This is due to the fact that the participants in World IPv6 Launch are some of the largest websites in the world. Five of the top six Alexa-rated web sites, collectively transmitting many gigabits per second of continuous Internet traffic, now offer their content over IPv6.

The key thing to remember is that IPv6 traffic volumes can vary greatly depending on where and how you are measuring the traffic. This is dramatically clear when you look at the ISOC IPv6 traffic measurement site. ISPs and organizations who have embraced IPv6 are seeing up to 50% of their traffic now using IPv6. However, Comcast measured their IPv6 traffic volumes at 1.5% of all their Internet traffic. Free in France sees almost 20% of their total traffic volumes as IPv6 transport.

Google has been measuring their IPv6 traffic volumes for several years as they have tested and explored and evangelized the importance of IPv6. Their published graph shows that their IPv6 traffic is 0.7% of all their traffic and the majority of this is native IPv6. That is good news because IPv6 tunneled traffic using 6to4 and Teredo contributed to much of the concern about "IPv6 Brokenness".

Arbor measures worldwide traffic volumes and DDOS threats using its ATLAS system. Last year IPv6 traffic was measured as peaking at 0.04% of all Internet traffic. This year Arbor measured IPv6 traffic peaking at 0.2% of all Internet traffic. Last year, native IPv6 traffic only made up 10% of all IPv6 traffic. This year, native IPv6 traffic is the majority of IPv6 traffic and tunneled IPv6 traffic is in the minority. These are good statistics and show that IPv6 is increasing even though it is quite small compared to IPv4.

Akamai also has a great page that shows their current number of IPv6 hits. Now Akamai is receiving almost 60,000 peak hits per second daily on IPv6. Compare this to the several hundred IPv6 hits per second that were received during last year's 24-hour duration World IPv6 Day.

What's Next?

Now that World IPv6 Launch is behind us, what can we expect to continue to drive adoption of IPv6? Hopefully we will continue to see the Alexa top-rated web sites migrate to IPv6 and leverage the CDNs like Akamai and Limelight Networks that have IPv6 support for their customers. We can expect that sites will continue to migrate to IPv6, although, there will not be a single date with promotional fanfare to help motivate organizations. Maybe we should make every June 6th IPv6 Day and continue to gauge the deployment of IPv6's growth each year.

We will likely see some U.S. Federal web sites become IPv6-capable in the September timeframe as these organizations strive to meet their mandate. However, on the whole, U.S. Federal government organizations have made lethargic progress on IPv6 and many of them will fail to meet their self-imposed mandate. The National Institute of Standards and Technology (NIST) Information Technology Laboratory, Advanced Network Technologies Division maintains a site that measures the governments transition to IPv6. These graphs show that the majority of federal organization's web sites have made no progress toward IPv6 deployment.

It is safe to predict that IPv6 adoption will continue to grow in the coming years, but it will trail IPv4 bandwidth for many years. It is important to keep in mind that for every HTTP connection that goes over IPv6, it is one less HTTP connection that was made with IPv4. We will start to see a tipping point once IPv6 grows to 10% of the total Internet bandwidth. Until that point, IPv6 will continue its slow and steady pace, and as they say "slow and steady, wins the race".

Scott