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Re: Priority signals in HTTP/2

From: Cory Benfield <cory@lukasa.co.uk>
Date: Fri, 18 Dec 2020 09:36:25 +0000
Message-ID: <CAH_hAJFK_pRTBCbQKvs6hiHQERG7nHBb+KDpuLX9FFLRYO1SAQ@mail.gmail.com>
To: Martin Thomson <mt@lowentropy.net>
Cc: HTTP Working Group <ietf-http-wg@w3.org>
I think this looks like a reasonable approach to me.

On Fri, 18 Dec 2020 at 02:26, Martin Thomson <mt@lowentropy.net> wrote:
>
> Now that we're official, I'd like to get started on some of the more difficult pieces: priority.
>
> I wrote up a proposed plan for dealing with the priority signaling in RFC 7540 here: https://github.com/httpwg/http2-spec/issues/773#issuecomment-725285414
>
> What do people think about this general approach (quoting):
>
> 1.    Cut the section with the detailed explanation and replace it with some explanatory text about the importance of having prioritization in a multiplexed transport (though not necessarily signaling thereof).
>
> 2.    Explain that this document used to define a priority signaling scheme, but that the one that was defined was unsuccessful.
>
> 3.    In that section recommend against using the priority signaling scheme from RFC 7540, but explain that other endpoints that you talk to might send these frames.
>
> 4.    Point to the new signaling system if that is mature enough (and probably even if it is not).
>
> 5.    Suggest, but not recommend, that servers pay attention to priority signals using these old mechanisms in the absence of other signals. This might take a little careful wording, but it's probably enough to caution that ignoring signals might degrade performance and some signals might be better than none. Point to RFC 7540 for the details of how the old scheme works.
>
> 6.    Leave the definition of the frame type intact, but cut the definitions right down to just the necessary pieces sizes, names, and any mandatory processing (error handling, sizes, ranges, the hard stuff). This should ensure that people are able to do things like generate the right error codes and skip over the HEADERS frame pieces properly.
>
> 7.    Leave text about when PRIORITY can be sent in the state machine. This is important for interoperating with endpoints that generate the frame.
>
>
>
Received on Friday, 18 December 2020 09:36:53 UTC

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