Happy Eyeballs – promoting a healthy IPv4 and IPv6 coexistence

By on 25 Jul 2016

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A recent study to measure the impact of the Happy Eyeballs (HE) algorithm has shown that 18% of Alexa’s top 10,000 websites are faster over IPv6 than IPv4.

IPv6 is picking up speed

In their research paper, presented at the Applied Networking Research Workshop 2016 in Berlin, authors Vaibhav Bajpai and Jürgen Schönwälder from Jacobs University in Bremen, Germany, also found that nearly all of the remaining sites (91%) were, at most, only 1 millisecond (ms) slower over IPv6 than IPv4.

Watch Vaibhav’s presentation from ANRW’16:

“The historical trend shows that only around 1% of the TCP connect times over IPv6 were ever above the HE timer value (300 ms), which leaves around 2% chance for IPv4 to win a HE race towards these websites.  As such, 99% of these websites prefer IPv6 connections more than 98% of the time,” the research says.

“We show that although absolute TCP connect times (in ms) are not that far apart in both address families, HE with a 300 ms timer value tends to prefer slower IPv6 connections in around 90% of the cases…[and] that lowering the HE timer value to 150 ms gives us a margin benefit of 10% while retaining same preference levels over IPv6.”

Using a three-year (2013-2016) dataset compiled from using an active test (happy) that measures TCP connection establishment times, the study showed that TCP connection times to popular websites over IPv6 have improved considerably.

The paper is open-access and available to download from the ACM Digital Library Website.

What is Happy Eyeballs?

Happy Eyeballs (also called Fast Fallback) is an algorithm published by the IETF that can make dual-stack applications more responsive to users by determining which transport would be better used for a particular connection by trying them both in parallel.

The algorithm and its requirements are described in RFC 6555, “Happy Eyeballs: Success with Dual-Stack Hosts”.

Below is a description from Geoff Huston on how it works:

“The proposed approach is simple – if the client system is dual stack capable, then fire off connection attempts in both IPv4 and IPv6 in parallel, and use (and remember) whichever protocol completes the connection sequence first.”

“The user benefits because there is no wait time and the decision favours speed – whichever protocol performs the connection fastest for that particular end site is the protocol that is used to carry the payload.

“The approach is also resilient, in so far as either protocol can be unresponsive, but this unresponsiveness is completely invisible to the end user.”

Want to check whether you’re using IPv6?

Firefox and Chrome have several plugins / extensions that allow you to see if you’re being delivered sites on IPv4 or IPv6, including IPvFox and SixOrNot (Firefox), and IPvFoo (Chrome).

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The views expressed by the authors of this blog are their own and do not necessarily reflect the views of APNIC. Please note a Code of Conduct applies to this blog.

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