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Re: Pipeline hinting revisited

From: Roy T. Fielding <fielding@gbiv.com>
Date: Fri, 12 Aug 2011 14:44:53 -0700
Cc: ietf-http-wg@w3.org
Message-Id: <0AF7CCCA-CC03-43F2-A163-93C4847D19BA@gbiv.com>
To: Brian Pane <brianp@brianp.net>
Pipeline failures are almost never due to HTTP issues and cannot
be hinted at within HTTP.  They are due to 

  a) non-HTTP intermediaries interfering with communication, and
  b) specific resources that hog or close the connection

Hinting in HTTP (aside from "Connection: close") will not help
either one.  Hinting within the mark-up and/or links might help (b).
Using a session-level MUX below HTTP would work, of course, but
can't actually be deployed because of (a).

In short, I think it is time to stop trying to make HTTP fix all
the things wrong with TCP.  It is just as hard to deploy HTTP
changes now as it was to deploy TCP changes in 1994.  What might
work, without protocol changes, is to use a host or pathname
convention that says all of the resources on *this* site are
good for pipelining.  Ugly as heck, but it would work well enough
for the use cases where pipelining helps the most (embedded stuff).

Or simply convince the browser developers to implement visible
(transient and non-interrupting) error messages when pipelining fails.

....Roy
Received on Friday, 12 August 2011 21:45:17 GMT

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