Re: [v6ops] Measuring the Effectiveness of Happy Eyeballs

[Dan Wing <[e-mail]>]

On Jul 4, 2013, at 6:02 AM, "Bajpai, Vaibhav" <[e-mail]> wrote:

> Hello,
> 
> I would like to request a 10-minute presentation slot 
> at the upcoming IETF 87 to present my PhD work:
> 
> Title:		 Measuring the Effectiveness of Happy Eyeballs
> Authors:	 Vaibhav Bajpai and Jürgen Schönwälder
> URL:             http://tools.ietf.org/html/draft-bajpai-happy-00
> 
> Abstract:
> 
>  The IETF has developed solutions that promote a healthy IPv4 and IPv6
>  co-existence.  The happy eyeballs algorithm for instance, provides
>  recommendations to application developers to help prevent bad user
>  experience in situations where IPv6 connectivity is broken.  This
>  document describes a metric used to measure the effectiveness of the
>  happy eyeballs algorithm.  The insights uncovered by analysing the
>  data from multiple locations is discussed.

I noticed when this was published and presented earlier at https://ripe66.ripe.net/presentations/263-ripe66-happy-slides.pdf.  It's nice to see it published as an Internet Draft, but disappointing that the underlying Effective Measurement is testing something other than Happy Eyeballs.

Happy Eyeballs is doing what it was designed to do -- provide a good user experience when the IPv6 (or IPv4) path is down.  However, draft-bajpai-happy did not evaluable how well Happy Eyeballs handles a broken IPv6 or broken IPv4 path.  Instead, what draft-bajpai-happy measured was how well the selected path functioned.  Happy Eyeballs biases its path selection towards IPv6 by design (150-250ms timeout is suggested in http://tools.ietf.org/html/rfc6555#section-5.5).  The justification for this delay is explained in "Delay IPv4", http://tools.ietf.org/html/rfc6555#section-4.1, and was consensus of the working group primarily because it (a) mimics the long-standing IETF view that IPv6 should be preferred over IPv4 (b) reduces connection attempts on servers and (c) minimizes the harm to IPv4-only devices sharing an IPv4 address with the dual-stack client (as those IPv4-only devices cannot use IPv6).  Happy Eyeballs' algorithm differs from Apple's algorithm (introduced in OS X 10.7) which uses whichever path connects first (for details see http://lists.apple.com/archives/ipv6-dev/2011/Jul/msg00009.html), which I expect would result in better results if tested using the test methodology of draft-bajpai-happy.  However, even with Apple's algorithm if a path connects quickly but the path performs poorly (e.g., low bandwidth) the user experience will suffer.  Happy Eyeballs can perform similarly to Apple's algorithm (but not identically) by setting its connection delay to 0ms.

-d



> Thank you!
> 
> Best, Vaibhav
> 
> -----------------------------------------------------
> Vaibhav Bajpai
> 
> Research I, Room 86
> Computer Networks and Distributed Systems  (CNDS) Lab
> School of Engineering and Sciences
> Jacobs University Bremen, Germany
> 
> www.vaibhavbajpai.com
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