Re: IBM patents tunneling HTTP through another protocal

I won't attempt to inject an opinion into the debate over whether there
is "prior art" that might invalidate this patent (#5,754,774).  (I will
point out that people who know nothing about patent law are often
surprised by what is or is not a valid patent.)

But because it's usually pretty difficult to figure out what a patent
is really describing (especially one with 129 claims!), I thought it
might help to point out that several of the authors of this patent
have already published a readable and fairly complete paper:
	
	Barron C. Housel and David B. Lindquist
	"WebExpress: A System for Optimizing Web
		Browsing in a Wireless Environment"
	Proc. 2nd Annual Intl. Conf. on Mobile Computing and
		Networking
	ACM, New York, November 1996, 108-116

(from which one can infer that they probably came up with
the invention somewhat before the filing date on the patent).

As far as I know, this is the first publication to describe
the idea of "delta encoding" for HTTP (although I don't think
they used this term).

There have been several related documents published by others,
including myself:

	Gaurav Banga, Fred Douglis, and Michael Rabinovich
	"Optimistic Deltas for WWW Latency Reduction"
	Proc. 1997 USENIX Technical Conference
	Anaheim, CA, January 1997, pages 289-303

	Arthur van Hoff, John Giannandrea, Mark Hapner, Steve Carter,
	and Milo Medin.  The HTTP Distribution and Replication
	Protocol.  Technical Report NOTE-DRP, World Wide Web
	Consortium, August, 1997.
	http://www.w3.org/TR/NOTE-drp-19970825.html.

	Jeffrey C. Mogul, Fred Douglis, Anja Feldmann,
		 and Balachander Krishnamurthy.
	"Potential benefits of delta encoding and data compression
		for HTTP"
	Proc. SIGCOMM '97 Conference
	Cannes, France, September, 1997, pages 181-194
	Expanded version:
 	http://www.research.digital.com/wrl/techreports/abstracts/97.4.html

	Fred Douglis, Antonio Haro, and Michael Rabinovich.  HPP: HTML
	Macro-Preprocessing to Support Dynamic Document Caching.
	Proc.  USENIX Symposium on Internet Technologies and Systems,
	USENIX, Monterey, CA, December, 1997, pp. 83-94.

	J. Mogul, Y. Goland, A. van Hoff, F. Douglis, A. Feldmann,
		B. Krishnamurthy
	"Delta encoding in HTTP",
	draft-mogul-http-delta-00.txt
	13 Jan 1998


Our SIGCOMM '97 paper has some discussion of the related work in
this area.

-Jeff

Received on Friday, 5 June 1998 12:04:34 UTC