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Re: Questions on Frame Size

From: Roberto Peon <grmocg@gmail.com>
Date: Wed, 19 Jun 2013 23:44:58 -0700
Message-ID: <CAP+FsNd5Z3VgK6BBF6DJJdVdkdRj9bjdmKsKVcR_+cc3rSyrkQ@mail.gmail.com>
To: Shigeki Ohtsu <ohtsu@iij.ad.jp>
Cc: HTTP Working Group <ietf-http-wg@w3.org>
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> 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 06:45:28 UTC

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