Dear NANOG, A paper on measuring the effects of happy eyeballs [RFC 6555] just got accepted last week. This uses a 3-years long ('13 - '16) dataset of TCP connect times towards ALEXA top 10K websites collected from 80 dual-stacked SamKnows probes. We just released [a] the paper. Thought to share it along: [a] http://goo.gl/JmKEax Feedback most welcome! You may recall preliminary versions of this work at RIPE 66 [b] and IETF 87 [c]. [b] https://ripe66.ripe.net/archives/video/1208 [c] https://vimeo.com/71407427 Measuring the Effects of Happy Eyeballs --------------------------------------- The IETF has developed protocols that promote a healthy IPv4 and IPv6 co-existence. The Happy Eyeballs (HE) algorithm, for instance, prevents bad user experience in situations where IPv6 connectivity is broken. Using an active test (happy) that measures TCP connection establishment times, we evaluate the effects of the HE algorithm. The happy test measures against ALEXA top 10K websites from 80 SamKnows probes connected to dual-stacked networks representing 58 different ASes. Using a 3-years long (2013 - 2016) dataset, we show that TCP connect times to popular websites over IPv6 have considerably improved over time. As of May 2016, 18% of these websites are faster over IPv6 with 91% of the rest at most 1 ms slower. 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. 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. We show that lowering the HE timer value to 150 ms gives us a margin benefit of 10% while retaining same preference levels over IPv6. Best, Vaibhav =================================== Vaibhav Bajpai www.vaibhavbajpai.com Room 91, Research I School of Engineering and Sciences Jacobs University Bremen, Germany ===================================