On Fri, 11 Dec 2015, Daniel Stenberg wrote:

> Eh, sorry that wasn't very clear of me. It isn't necessarily *extra* round-trips,
> but it may require a few round-trips before HTTP/2 is finally used. Like for
> example many HTTP/2 servers don't do the upgrade on POST.

Ah yes now I understand, this relates to the possible use of OPTIONS as described in https://tools.ietf.org/html/rfc7540#section-3.2. I agree that this adds overhead and probably complexity to the client.

Let's see what we can do for prior knowledge in the future!

Lucas

> -----Original Message-----
> From: curl-library [mailto:curl-library-bounces_at_cool.haxx.se] On Behalf Of
> Daniel Stenberg
> Sent: 11 December 2015 12:27
> To: libcurl development <curl-library_at_cool.haxx.se>
> Subject: RE: intent to land: CURL_HTTP_VERSION_2TLS
>
> On Fri, 11 Dec 2015, Lucas Pardue wrote:
>
> > I agree with the extra size (although it is all relative) but are
> > there really additional round-trips?
>
> Eh, sorry that wasn't very clear of me. It isn't necessarily *extra* round-trips,
> but it may require a few round-trips before HTTP/2 is finally used. Like for
> example many HTTP/2 servers don't do the upgrade on POST.
>
> > I've been trying to find the time to look at 'h2c prior knowledge' in
> > curl/libcurl, still some way to go. Prior knowledge avoids upgrade
> > overhead but would need an option to signal usage, I think the new
> > argument creates a pathway for such an option.
>
> I think you're right. Once this goes in, I think we can have a look at adding
> another option and do prior-knowledge that way.
>
> (I have the code mostly done for 2TLS, I just fell over a test failure I need to
> sort out before I land this.)
>
> --
>
> / daniel.haxx.se
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Received on 2015-12-11