On 9 Jun 2011, at 13:07, Alan Buxey wrote:
>
> wasnt all this covered in the preface work for HappyEyeballs ?
>
> any client that takes the first DNS answer (as this appears to do)
> is broken - should wait a little longer for an answer for each query
> and then use HE to decide WHICH method to use - fixes the case
> when eg IPv6 address is given but theres no working connectivity
>
> you'd think that web browsers - which all can multithread and deal with
> background transfer and parallel processes/threads - could implement
> this far quicker/better than something thats traditionally a single
> thread/process :-|
Happy Eyeballs is about connection performance management, with the sliding p value indicating the headstart (if +ve) that IPv6 gets. It's about removing that potential long delay before your browser, if it prefers v6, falls back to v4. It's not about DNS response handling. Indeed, if the OS throws away a response, HE becomes rather moot.
Chrome does HE in a very simplistic way. p is fixed to 300ms. But that works to stop those timeouts.
Tim
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