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Re: #540: "jumbo" frames

From: Patrick McManus <pmcmanus@mozilla.com>
Date: Wed, 25 Jun 2014 15:30:36 -0400
Message-ID: <CAOdDvNrDFh7CVWofu_b-UPxCZKfHPjMm_2=1GXhx4_nKMFQNPg@mail.gmail.com>
To: Jason Greene <jason.greene@redhat.com>
Cc: Nicholas Hurley <hurley@todesschaf.org>, Mark Nottingham <mnot@mnot.net>, K.Morgan@iaea.org, Poul-Henning Kamp <phk@phk.freebsd.dk>, Willy Tarreau <w@1wt.eu>, Greg Wilkins <gregw@intalio.com>, IETF HTTP WG <ietf-http-wg@w3.org>, Martin Dürst <duerst@it.aoyama.ac.jp>
hey all -

> Extensions are length limited to 16KB, so to allow that you would have to
> define special framing rules, and if you have done that might as well apply
> it everywhere.

I don't think that's the case at all. un-acked extensions are limited that
way because you can't change the semantics of the protocol.. but once you
ack something you can do anything you like - including changing framing to
look like websockets via use one of the R bits (as an example). Go
bootstrap h3 that way if you feel so inclined to write an extension like

but maybe I have that wrong -(our extension text is brand new afterall) and
extensions are meant to preclude such hackery which seems odd - given they
are essentially a hackery escape hatch that already acknowledges the
ability to change semantics of existing elements. If that's true there is
always the alpn method of proving this can work - because I really don't
think it can work and leave h2 responsive.

> It’s a very common use-case.

unfortunately its one that is in direct competition with the driving reason
for h2: prioritized mux on one connection. Minimally you should prove out
that can coexist with jumbo frames because spdy showed us it was a problem.
You simply can't send a multi megabyte frame and also then respond quickly
to a CANCEL and a new GET on the same connection which is something any h2
implementation should be able to handle responsively. My H1 application
closes a ton of connections because of that pattern - h2 doesn't have to.
Its one of its under appreciated features. The cost of that feature, 16KB
frames, is reasonable imo.

and of course, then there is TLS.

ship it.
Received on Wednesday, 25 June 2014 19:31:03 UTC

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