From the dualstack-is-fun department...

Cameron Byrne cb.list6 at
Tue Mar 1 08:31:08 CET 2011

On Feb 28, 2011 10:41 PM, "Andrew Yourtchenko" <ayourtch at> wrote:
> Daniel,
> 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
> discussion.
> 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.

This also creates the ugly situation where customer calls help desk saying
website x is down, support person tries to get to website x, and it works.
Help desk says, nope "works for me" and the broken ipv6 access or dare I say
ipv4 access is broken to the none-HE user but works for the HE user. If the
none he-user cannot easily convince others that there is a problem, that is

This is a support nightmare as HE masks the issue and will not be uniformly
deployed -- ever.

This is a classic dilemma. Masking the problem ostensibly makes it go away,
but at the same time exacerbates the ability to resolve it. It is kind of
like beer :) and beer is good, especially when I been troubleshooting
connectivity issues all day and my customers keeping telling me  websites
are down
... but not all of them ... they all but works for me ....

> cheers,
> andrew
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