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Re: Connection limits

From: Adrien de Croy <adrien@qbik.com>
Date: Thu, 06 Mar 2008 10:05:31 +1300
Message-ID: <47CF0B1B.9050300@qbik.com>
To: "Roy T. Fielding" <fielding@gbiv.com>
CC: "Josh Cohen (MIG)" <joshco@windows.microsoft.com>, David Morris <dwm@xpasc.com>, Mark Nottingham <mnot@yahoo-inc.com>, "ietf-http-wg@w3.org Group" <ietf-http-wg@w3.org>

I agree

If pipelining is sending another request on a connection before you get 
a response, then as far as I can tell, all the major browsers by default 
do it.

And I don't think it makes any sense to try and come up with a magic 
number for connections.  The TCP overhead is a lot lower now with 
persistent connections which are now ubiquitous, so maybe the 
requirement for many connections is reduced, but policy decisions like 
that should be left to server or proxy admin/management (people), not 
hard coded into software or written into specs.


Roy T. Fielding wrote:
> On Mar 5, 2008, at 4:52 AM, Josh Cohen (MIG) wrote:
>> I would agree.
>> The connection limit, in addition to the bandwidth limitations of the 
>> time, also helped the servers themselves.  Back then, maintaining 
>> many simultaneous but short lived TCP connections was inefficient for 
>> many operating systems TCP stacks.  By switching to fewer, longer 
>> standing connections, and the hope of the use of pipelining, we 
>> thought we'd address that.
>> Nowadays with stacks much more efficiently tuned to handle these 
>> types of connections efficiently, and the non-occurrence of 
>> pipelining, I think this could be relaxed a bit.
> Just out of curiosity, why do people keep saying things like 
> "non-occurrence
> of pipelining" when the vast majority of connections I've looked at over
> the past six years contain obviously pipelined GET requests and 
> occasional
> pipelines of POST (in spite of the bogus requirement).  Is this just 
> because
> you do all your work behind a corporate firewall proxy?  Is this just
> another myth?  Or am I the only one on the planet who looks at traces to
> servers using both a client and a server that support pipelining?
> Er, in regards to the topic, I see no reason for the connection limits.
> They should be replaced with a simple statement of why too many 
> connections
> results in counterproductive collision/bandwidth effects.
> ....Roy

Adrien de Croy - WinGate Proxy Server - http://www.wingate.com
Received on Wednesday, 5 March 2008 21:04:32 UTC

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