Re: [Doh] How to start HTTP/2?

On Tue, Jan 16, 2018 at 10:21 AM, Stephane Bortzmeyer <bortzmeyer@nic.fr>
wrote:

> On Tue, Jan 16, 2018 at 04:12:39PM +0100,
>  Daniel Stenberg <daniel@haxx.se> wrote
>  a message of 27 lines which said:
>
> > If you stick to HTTPS (which the spec says we must in section 4)
> > then there's only one way: negotiate HTTP version with ALPN. It also
> > happens to be the easiest way for clients IMHO.
>
> OK, but could it be better to say explicitely "Servers and clients
> MUST start HTTP/2 using the ALPN extension of TLS, as specified in RFC
> 7540, section 3.3"?
>
>
imo, no.. a] h2 isn't required.. and even where its a should it is h2 or
its successors. successors might do it differently.

b] a large point of using h2 as a substrate is that you just reuse h2 and
don't need to restate things (possibly incorrectly by accident)

c] h2 can be extended in ways that could conflict with that language. I
don't see the value in forcing those extensions to be aware enough to also
extend DoH.

> (Then, what a server should do if the client did not use ALPN? Start
> HTTP/2 anyway, because of the robustness principle?)
>
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