From the dualstack-is-fun department...

Andrew Yourtchenko ayourtch at
Tue Mar 1 07:41:45 CET 2011


On Tue, Mar 1, 2011 at 1:34 AM, Daniel Roesen <dr at> wrote:
> On Tue, Mar 01, 2011 at 12:07:36AM +0000, Bjoern A. Zeeb wrote:
>> And, would you have noticed the IPv6 related bug if happy-eyeballs was
>> already implemented or would legacy IP have worked well enough for you
>> to not notice (read as - what's better?, getting the bug fixed or not
>> noticing and harming IPv6 for longer)?
> IPv6 is not customer-driven, but provider driven. So #1 priority must be
> that "things keep working" as painless as possible.
> But you're right in the sense that with Happy Eyeballs we need methods
> to measure problems being masked by HE. How, is one of the things
> which seem to be missing in the Happy Eyeballs discussion.

Totally agree. Like I told to Bjoern when we met in @fosdem a few
weeks ago - from the pure engineering point of view I think a good
thing that could happen is IPv4 would suddenly vanish from the face of
earth for 3-4 months. Then we notice all the problems and can fix them
(very fast ;-) (Un)fortunately this is not possible - as it would be a
major catastrophy from the user experience point of view.

Happy Eyeballs is a bit on the other side of the spectrum - by working
hard to make the UX as seamless as possible indeed it masks these
kinds of problems - so with it the chances are high that these
problems will not be noticed. Actually, even more so since the
opportunistic connection establishment that you mentioned in the first
mail might not even happy if the single protocol consistently wins (so
it is not 100% true about the increase in load).

We plan a bar bof @Prague, I will definitely bring this topic up there
too - meantime if you have ideas, feel free to write them up for the

Side remark: I noticed this trend overall - the more robust you have a
protocol to external influences (soft failures instead of hard
failures), the "nicer" is the user experience, and the more hell is in
debugging of this protocol for the support/dev folks when the
experience slowly degrades to the point of being unacceptable. It's a
tough choice.


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