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Re[4]: multiplexing -- don't do it

From: Adrien W. de Croy <adrien@qbik.com>
Date: Sun, 01 Apr 2012 21:39:15 +0000
To: "Peter L" <bizzbyster@gmail.com>
Cc: "Willy Tarreau" <w@1wt.eu>, "Mike Belshe" <mike@belshe.com>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
Message-Id: <emace164a3-942d-48bc-8996-0aa1a41b78b8@BOMBED>
  
Hi Peter
  
in my experience, the reason packet captures get created in the first 
place, is because someone has noticed a _recurring_ problem and is 
trying to debug it / track it down.
  
therefore it may take a bit more work to get a full capture that does 
go back far enough, but is usually possible, even if initial captures 
don't.
  
Our proposal for 2.0 doesn't apply gzip to the stream though, but does 
cache headers across a hop, so could be said to suffer from a similar 
problem, since depending how far back a capture goes, you may miss the 
transfer of some headers.
  
It could probably have a mode to disable this per-hop caching though.
  
Adrien
  
  

------ Original Message ------
From: "Peter L" <bizzbyster@gmail.com>
To: "Adrien W. de Croy" <adrien@qbik.com>
Cc: "Willy Tarreau" <w@1wt.eu>;"Mike Belshe" 
<mike@belshe.com>;"ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
Sent: 2/04/2012 9:33:54 a.m.
Subject: Re: Re[2]: multiplexing -- don't do it
>It's not just a matter of reading a binary format. SPDY gzip needs a synch point. So there definitely will be times (when the capture does not go far enough back in time) when tools will not be able to decode the compressed headers.
>
>This is undesirable in my opinion. Seems strange that others do not agree.
>
>Thanks for putting up with reading my concerns.
>
>:-)
>
>Peter
>
>On Apr 1, 2012, at 5:25 PM, "Adrien W. de Croy" <adrien@qbik.com> wrote:
>
>
>>
>>I agree as well, even though it will also cause me some pain.
>>We've been debugging binary / non-text / non-human-readable protocols for decades.  DNS and DHCP are 2 that spring immediately to mind.
>>Common network analysers shouldn't have much trouble decoding what has been proposed.
>>Adrien
>>
>>------ Original Message ------
>>From: "Willy Tarreau" <w@1wt.eu>
>>To: "Mike Belshe" <mike@belshe.com>
>>Cc: "Peter L" <bizzbyster@gmail.com>;"ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
>>Sent: 1/04/2012 4:39:43 p.m.
>>Subject: Re: multiplexing -- don't do it
>>
>>>
>>>On Fri, Mar 30, 2012 at 03:22:12PM +0200, Mike Belshe wrote:
>>>
>>>
>>>>
>>>>
>>>>What is "transparency on the wire"?  You mean an ascii protocol that you
>>>>can read?  I don't think this is a very interesting goal, as most people
>>>>don't look at the wire.
>>>>
>>>>
>>>
>>>
>>>
>>>I agree with you here Mike, despite being used to look at network captures
>>>all the day and testing proxies with "printf|netcat" at both ends. But we
>>>must admit that if developers need tools, they will develop their tools.
>>>Having an HTTP option for netcat would work well, or even having an 1.1-to-2.0
>>>and 2.0-to-1.1 message converter on stdin/stdout would do the trick. So I
>>>prefer to lose the ability to easily debug and have something efficient than
>>>the opposite. And it costs me a lot to say this :-)
>>>
>>>Willy
>>>
>>>
>>>
>>>
>>>
>
Received on Sunday, 1 April 2012 21:39:43 GMT

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