Re: Git Issues: PING

William Chan (陈智昌) <willchan@chromium.org> Sat, 20 April 2013 20:52 UTC

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To: James M Snell <jasnell@gmail.com>
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Subject: Re: Git Issues: PING
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+jpinner who filed the issue

Unless anyone comes up with a motivating reason to add arbitrary payloads,
let's just disallow them. This is what the SPDY/2 spec originally did (
http://dev.chromium.org/spdy/spdy-protocol/spdy-protocol-draft2#TOC-PING):
"Length: This frame is always 4 bytes long."

Unless I missed a PING discussion elsewhere, it looks refactoring
accidentally introduced a semantic change. Let's fix that.


On Sat, Apr 20, 2013 at 12:37 PM, James M Snell <jasnell@gmail.com> wrote:

> Per https://github.com/http2/http2-spec/issues/68 ...
>
> The question is: "In the current draft, the PING frame requires the
> server to resend an arbitrarily large payload.... Perhaps restrict the
> length of the PING frame to 0, allow any stream identifier in the
> header require the server to echo the identifier? ... I'm not sure
> what benefit being able to echo arbitrary contents provides."
>
> Placing a cap on the size of the Ping payload makes sense. Whether
> that cap should be strictly mandated by the spec or established via
> SETTINGS is an open question, however. Perhaps the spec ought to place
> a strict upper limit and allow recipients to optionally specify a more
> restrictive value via SETTINGS?
>
> - James
>
>