Re: http/2 initial limits - i see flow control initial limits specified, but not stream limits

Roberto Peon <grmocg@gmail.com> Sat, 04 May 2013 01:56 UTC

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Date: Fri, 3 May 2013 18:55:21 -0700
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From: Roberto Peon <grmocg@gmail.com>
To: Martin Thomson <martin.thomson@gmail.com>
Cc: James M Snell <jasnell@gmail.com>, =?UTF-8?B?V2lsbGlhbSBDaGFuICjpmYjmmbrmmIwp?= <willchan@chromium.org>, HTTP Working Group <ietf-http-wg@w3.org>
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Subject: Re: http/2 initial limits - i see flow control initial limits specified, but not stream limits
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Yup, the language in the specs is the same as what is currently in the
HTTP/2 spec, but people have been interpreting them differently (or at
least I assume so).

   - 4 - SETTINGS_MAX_CONCURRENT_STREAMS allows the sender to inform the
   remote endpoint the maximum number of concurrent streams which it will
   allow. By default there is no limit. For implementors it is recommended
   that this value be no smaller than 100.

is the thing in question, and most implementations that I know of default
to 100, which makes sense given that "no limit" and "unlimited" are not
always the same.
-=R


On Fri, May 3, 2013 at 3:46 PM, Martin Thomson <martin.thomson@gmail.com>wrote:

> On 3 May 2013 14:22, Roberto Peon <grmocg@gmail.com>; wrote:
> > This does differ from SPDY,
>
> This doesn't differ from the SPDY we were given.
>
> > but (still) seems reasonable given the number of
> > streams created in the initial RTT shouldn't be unbounded anyway.
> > Assuming we have persisted settings (which is in doubt, I guess), this
> would
> > only be a problem for the first RTT in a session where we didn't have the
> > persisted setting.
>
> I think that this default is under contention still:
> https://github.com/http2/http2-spec/issues/40
>
> We may ultimately determine that some value between 0 (what #40
> proposes) and infinity (status quo) is more appropriate.
>