[ipv6-wg] Happy Eyeballs bias

In your letter dated Wed, 26 Oct 2016 17:04:18 +0200 (CEST) you wrote:
>but 
>instead recommend the OS vendor to install some kind of heuristic to flag 
>for the user somehow that their IPv6 connectivity is degraded, and offer 
>to fault find it... or let's invent some kind of telemetry where these 
>kinds of breakages can be reported to the OS vendor so they can contact 
>the ISP and alert them to the breakage?

I wonder, if a host has a global IPv6 address that is not derived from any
kind of transition technology or tunnel, and setting up a TCP connection is
either slow or fails, then what percentage is due to an issue close to the
host and what percentage close to the target.

I.e., if IPv6 is broken is there any reason to believe it is often enough
due to ISP provided services that is would be worth reporting it in a 
roudabout way.

>Also, we still have the problem with PMTU blackhole detection and 
>mitigation. Why isn't this turned on more?

I really don't understand this. I guess 'everybody' doing major operating 
systems still lives in an IPv4-only world with MSS clamping.