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Re: #385: HTTP2 Upgrade / Negotiation

From: 陈智昌 <willchan@chromium.org>
Date: Tue, 23 Oct 2012 21:12:56 -0700
Message-ID: <CAA4WUYjQHpnFear2Ptya7nxdz4atgqNrQw=swGn=Gu7HLvk-AQ@mail.gmail.com>
To: Mark Nottingham <mnot@mnot.net>
Cc: "ietf-http-wg@w3.org Group" <ietf-http-wg@w3.org>
On Mon, Oct 22, 2012 at 7:50 PM, Mark Nottingham <mnot@mnot.net> wrote:
>
> On 23/10/2012, at 1:33 PM, William Chan (陈智昌) <willchan@chromium.org> wrote:
>
>> Overall, sounds good. I've included some clarifications/questions below.
>
> [...]
>
>>> Who's willing to do some experimentation? Specifically, does anyone have access to the code that was used before (IIRC, people bought some ads and inserted some Java to probe the network)?
>>
>> Do you mean the Chromium HTTP upgrade experiment agl referred to in
>> http://www.ietf.org/mail-archive/web/tls/current/msg05593.html?
>
> No, IIRC there was also some broader experimentation using ads; I'll dig around a bit more.
>
> Of course, if Chrome (or any other browser) would be interested in running an experiment, we'd love to do that too -- provided we can have input into the design.

Is there anything you'd like to change about the design in
http://www.ietf.org/mail-archive/web/tls/current/msg05593.html? I'm in
general supportive of running experiments, I just don't want to waste
our time unless there was something deficient about the previous
experiment. Also, I suspect a non-Google experiment would carry more
weight :) External validation is good.

On that point, at Realtime Conf today, Arnout Kazemier provided a
bunch of data on issues with WebSockets deployment.
https://speakerdeck.com/3rdeden/realtimeconf-dot-oct-dot-2012. As he
says "tl;dl: Always use SSL".

>
>
>>> Does anyone object to us defining such a record (type TBD), as long as it's not the only way to get to HTTP/2 for HTTP URIs?
>>
>> I'm not sure if my previous emails were taken to indicate "interest"
>> here. I forget what I said too :) As long as this is more of an
>> optional optimization than anything, I guess I'm OK with it. I'm very
>> much concerned about relying on it, due to experiments we have run
>> with TXT records that show us noticeably higher failure rates in
>> comparison to port 443, higher latency (we'd definitely have to race
>> this), and extra DNS queries.
>
> Yes, I think relying on it would be a mistake, for a variety of reasons.
>
>
>>> 2) Using a response header to hint that HTTP/2 is available on another port.
>>>
>>> This approach hasn't been talked about in detail yet, but it apparently (as some have noted) has the disadvantage of not upgrading the first interaction, and of requiring a separate cache (and caching model) for this information.
>>
>> Just to be clear, SRV records also have the disadvantage of not
>> upgrading the first interaction, unless you block on the response,
>> which Chromium definitely is not going to do unless the environment
>> changes such that it doesn't kill performance.
>
>
> I'll leave it to the DNS experts to debate the capabilities and merits here.
>
>
> --
> Mark Nottingham   http://www.mnot.net/
>
>
>
Received on Wednesday, 24 October 2012 04:13:23 GMT

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