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Re: Suggestion for NEW Issue: Pipelining problems

From: Yngve Nysaeter Pettersen <yngve@opera.com>
Date: Wed, 18 Jul 2007 01:05:11 +0200
To: "Travis Snoozy" <ai2097@users.sourceforge.net>
Cc: ietf-http-wg@w3.org
Message-ID: <op.tvms2xofvqd7e2@killashandra-ii.oslo.opera.com>

On Tue, 17 Jul 2007 16:22:15 +0200, Travis Snoozy  
<ai2097@users.sourceforge.net> wrote:

> On Tue, 17 Jul 2007 13:04:14 +0200, "Yngve N. Pettersen (Developer
> Opera Software ASA)" <yngve@opera.com> wrote:
>> Hello all,
>> I thought I should mention this particular issue I am seeing.
>> There are a number of servers that does not handle pipelining at all
>> well.
> <snip>
> ... and?
> More important than pointing out a bunch of bad implementations is
> to point out what's wrong with the RFC that led to the bad
> implementations. However, pipelining is pretty cut-and-dried -- I don't
> know that the RFC can make it much clearer than it already is. If you
> see ambiguities in the RFC that lead to these differing server
> behaviors, though, please do identify them.

What we have here is, indeed, incorrect implementations.

However, it is something that I think this group should be aware of, and  
perhaps address in some fashion, if possible.

There is quite some variation in the problems encountered, and their  
severity, from the less serious cut-or-hang-the-connection variations, to  
skip-requests to the variations I forgot to mention in my initial mail:  
the ones folding two responses into each other, and the ones that performs  
a response card shuffle. The most serious of the latter include the  
transparent proxies of major internet security suites (the ones I am aware  
of are Panda and Symantec, although I have not yet investigated fully what  
they are doing).

The question is if something can be done with the existing system, for  
example by adding some headers, or should a new system be created?

The two pipeline capable clients I am aware of at present is Opera and the  
Mozilla engine, although Mozilla's is disabled by default. I don't know  
what capabilities IE7 and KDE have in this area.

Serverside, both Apache and IIS 6 are AFAIK fully pipeline capable.

The problems I have been seeing the past few years have appeared to be  
caused by intermediate servers or frontends, which may work as  
loadbalancers or reverse proxies. The problem with these is that there is  
no way to detect them.

Yngve N. Pettersen
Senior Developer		                 Email: yngve@opera.com
Opera Software ASA                   http://www.opera.com/
Phone:  +47 24 16 42 60              Fax:    +47 24 16 40 01
Received on Tuesday, 17 July 2007 23:04:59 UTC

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