IP: new version of HTTP

[David Farber <farber () cis upenn edu>]

From: Marcel Waldvogel <mwa () ebony ccrc wustl edu>
Date: Mon, 17 Feb 97 14:01:37 -0600
To: farber () cis upenn edu
Subject: Re: IP: New version of HTTP is expected to cut Web delays


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In article <5e98un$l8f () olympus wustl edu>, you wrote:
> Unfortunately there is nothing said about what the whitch doctors have
> brewed but sounds like they fixed a sloppy design  -- djf


The magic thing is called P-HTTP (Pipelined HTTP, RFC2068), which
can also take advantage of Transaction TCP. P-HTTP cuts down the
number of TCP connection establishment/teardown phases (one per
server and no longer one for the text of each page, one per image,
...) and TTCP speeds up the connection establishment phase.


I'm aware of proposed improvements further reducing round-trip
delays. Some of the results will be released soon.


- -Marcel


To: farber () cis upenn edu
Date: Mon, 17 Feb 97 09:00:05 -0800
From: Craig Partridge <craig () aland bbn com>




Dave:


[I know you know this stuff -- some IPers may not]
    
    The HTTP 1.1 fix is to allow multiple documents to be sent via the
same TCP connection.


    The problem with the basic HTTP spec is that it opened a new TCP
connection for each item (document, image, whatever) on a page.  The first
thing a new TCP connection does is probe to figure out how much bandwidth
is available.  This process is known as slow-start.  Generally speaking,
it is done while the first few kilobytes of data are transferred.  During
that time, TCP isn't running at full speed.  Since most HTTP documents are
only a few kilobytes long, this means every HTTP document transfer is being
done while TCP is running inefficiently.  Note that the frequent fix of
running multiple TCPs in parallel doesn't really fix this problem --
you get higher performance, but what you're doing is running 2, 4 or 6
inefficient TCPs in parallel (which isn't good for the net).


    HTTP 1.1 fixes this problem (along with a bunch of other enhancements).


Craig Partridge