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IP: new version of HTTP
From: David Farber <farber () cis upenn edu>
Date: Mon, 17 Feb 1997 16:54:48 -0500
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 -----BEGIN PGP SIGNED MESSAGE----- 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
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- IP: new version of HTTP David Farber (Feb 17)