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Re: Questions on Frame Size

From: Shigeki Ohtsu <ohtsu@iij.ad.jp>
Date: Thu, 20 Jun 2013 16:09:45 +0900
Message-ID: <51C2AAB9.2060908@iij.ad.jp>
To: ietf-http-wg@w3.org
Thanks for your answer. I'm aware that the spec is still work-in-progress
for a new layering design but I was suprised that both two descriptions
about 16K limit and 64K requirements was newly added with the same commit.

The spec only covers HTTP so that the description of 64K requirements confused me.

(2013/06/20 15:44), Roberto Peon wrote:
> The spec is in flux w.r.t. layering, where this will be clarified.
> Right now, as I understand it, however, the intent is that HTTP will be limited to 16k frame sizes, and anything larger would get you a protocol
> error or similar.
> -=R
> On Wed, Jun 19, 2013 at 10:32 PM, Shigeki Ohtsu <ohtsu@iij.ad.jp <mailto:ohtsu@iij.ad.jp>> wrote:
>     Hi,
>     The issues about frame size were discussed and might had some
>     agreements at SF interium but please let me ask some questions on the
>     current spec of "3.3.2 Frame Size" which is updated by
>     https://github.com/http2/http2-spec/commit/fd703b572cfc527582c0716e59f2c4044ae195a8
>     1. "For instance, individual DATA and HEADERS frames used to express
>     HTTP request and response messages (see Section 4) are not permitted
>     to exceed 16,383 octets of payload."
>     PUSH_PROMISE is not listed.
>     Is the data size of PUSH_PROMISE also limited to 16K or is it exceptional
>     for some reason?
>     2. "The absolute maximum amount of payload data any individual frame
>       can contain is 65,535 octets. All implementations SHOULD be capable
>       of receiving and minimally processing frames up to this size."
>     If PUSH_PROMISE has a 16K limit, the max frame size is still 64K,
>     however, any other frames besides DATA, HEADERS and PUSH_PROMISE
>     are only several octets at most.
>     Is it for the future extension not to change the frame length to 14bit?
>     If so, why the spec requires all implementations to support the 64K frame
>       size only for the future extension?
>     Regards,
Received on Thursday, 20 June 2013 07:10:14 UTC

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