2016-12-02 9:19 GMT+09:00 Martin Thomson <martin.thomson@gmail.com>:
> On 2 December 2016 at 11:09, Mark Nottingham <mnot@mnot.net> wrote:
> > In particular, my recollection of the outcome of the discussion of WS in
> H2 was that a new SETTING or a new ALPN token could be used to indicate
> that a connection supports both H2 and WS. If there's a problem with doing
> so, that would be good to talk about as well. Especially considering QUIC.
>
> There seems to be some reluctance to exercise that option. I don't
> understand why; I've a bunch of candidate theories, but none of them
> make a lot of sense.
>
>
My understanding is that the cons of using SETTINGS only is that it
requires an additional roundtrip on connection establishment. I've heard
people oppose to the use of ALPN since they want to use both H2 and WS (and
possibly DNS?) on the same connection.
Personally, I think using both SETTINGS (or introducing a new frame) and
ALPN solves the shortcomings (and the reluctance). We could consider ALPN
as a method to specify the application protocol (e.g. HTTP or WS or DNS),
and use SETTINGS for permitting additional protocols to be coalesced.
--
Kazuho Oku