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Re: #40 - HTTP2 default value for client supported max_concurrent_streams

From: 陈智昌 <willchan@chromium.org>
Date: Sat, 23 Feb 2013 07:09:11 -0800
Message-ID: <CAA4WUYjUTkJk1EdJ_N6w_8VPCu7cSZ8aTceO7r=ojX8b5bmuXA@mail.gmail.com>
To: Amos Jeffries <squid3@treenet.co.nz>
Cc: HTTP Working Group <ietf-http-wg@w3.org>
Sorry, I did not explicitly state a conditional that I thought was
implicitly understood.

*In situations where the server wants to push resources*, if the majority
of clients disable HTTP/2 stream push, then servers will simply inline
resources instead.

You're right that push can always be abused. But in situations that it
makes sense to push, it's better to use HTTP/2's push facility than to
inline resources. And we should ensure that the push mechanism remains
viable, otherwise servers will just inline in those situations.

On Sat, Feb 23, 2013 at 3:03 AM, Amos Jeffries <squid3@treenet.co.nz> wrote:

> On 23/02/2013 10:29 a.m., William Chan (陈智昌) wrote:
>> Let's be careful about this issue, because as we've noted many times
>> before, if the server can't leverage HTTP/2 to push streams, it is likely
>> to just inline resources directly, which is definitely worse.
>> Fundamentally, when the client issues a request, the server can send
>> anything it wants in the response. Defaulting to 0 would most likely
>> incentivize servers to to just inline resources, which is probably worse
>> than sending push streams to clients which don't want it (I assert that in
>> the open web, this should be a minority. If not, then HTTP/2 stream pushing
>> will have failed and people will just inline resources).
> Sorry I just parsed that as a re-wording of "if it turns out the majority
> of clients disable push we can consider it failed and servers will just do
> it via inlining anyway."
> If that is the case, why are sites not already inlining _all_ of their
> page content and pushing it on first contact from any client. The answer
> should be obvious that it is a waste of resources for both client and
> server to do this at all on any large scale. Although, that said I'm still
> fielding questions about how to pre-cache entire sites like facebook and
> google :-( there will always be idiots whatever gets specified.
> Amos
>> On Fri, Feb 22, 2013 at 1:02 PM, Gabriel Montenegro <
>> Gabriel.Montenegro@microsoft.**com <Gabriel.Montenegro@microsoft.com><mailto:
>> Gabriel.Montenegro@**microsoft.com <Gabriel.Montenegro@microsoft.com>>>
>> wrote:
>>     There is harm borne by the unwilling client receiver: battery and
>>     data allowance are not free.
>>     *From:*Roberto Peon [mailto:grmocg@gmail.com
>>     <mailto:grmocg@gmail.com>]
>>     *Sent:* Friday, 22 February, 2013 08:24
>>     *To:* Martin Thomson
>>     *Cc:* Osama Mazahir; ietf-http-wg@w3.org
>>     <mailto:ietf-http-wg@w3.org> Group
>>     *Subject:* Re: #40 - HTTP2 default value for client supported
>>     max_concurrent_streams
>>     Yup, I understand that part. :)
>>     I'm doing a poor job of pointing out that any harm done by doing
>>     something like this is borne by the party doing it.
>>     ... so why mandate it-- if there turns out to be a positive
>>     benefit of doing such a push in the future, fine.
>>     I guess I'm attempting to argue that, unless we can figure out how
>>     this causes harm/is likely to be done accidentally and cause
>>     issues, then it is better to not say anything about it. Saying
>>     something about it creates a spec with is more fragile.
>>     -=R
>>     On Fri, Feb 22, 2013 at 8:19 AM, Martin Thomson
>>     <martin.thomson@gmail.com <mailto:martin.thomson@gmail.**com<martin.thomson@gmail.com>>>
>> wrote:
>>         On 22 February 2013 05:29, Roberto Peon <grmocg@gmail.com
>>         <mailto:grmocg@gmail.com>> wrote:
>>         > What is the motivation for that?
>>         I'm not suggesting that this is Osama's motivation, but look
>>         at the
>>         Upgrade scenario: the server is the first to send on the HTTP/2.0
>>         session with a response. There's an obvious opportunity there
>>         to push
>>         prior to the client SETTINGS frame arriving. The TLS scenario
>>         is less
>>         interesting - the client sends SETTINGS prior to any request,
>>         making
>>         defaults non-interesting.
Received on Saturday, 23 February 2013 15:09:39 UTC

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