`
`By: John D. Vandenberg (Reg. No. 31,312)
`
`john.vandenberg@klarquist.com
`Stephen J. Joncus (Reg. No. 44,809)
`stephen.joncus@klarquist.com
`Klarquist Sparkman LLP
`One World Trade Center, Suite 1600
`121 S.W. Salmon Street
`Portland, Oregon 97204
`Telephone: (503) 595-5300
`Facsimile: (503) 595-5301
`
`
`
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`____________
`
`MICROSOFT CORPORATION
`Petitioner
`
`v.
`
`PROXYCONN, INC.
`Patent Owner
`
`____________
`
`
`Patent 6,757,717 B1
`
`____________
`
`SECOND PETITION FOR INTER PARTES REVIEW OF
`CLAIMS 6, 7, 9, 11, 12 and 14 OF U.S. PATENT NO. 6,757,717
`
`
`
`FILED VIA PRPS ON: January 11, 2013
`
`TABLE OF CONTENTS
`
`Page
`INTRODUCTION ........................................................................................... 4
`
`’717 PATENT (EX. 1002) ............................................................................... 5
`
`I.
`
`II.
`
`III. CHALLENGED CLAIMS AND THEIR
`BROADEST REASONABLE INTERPRETATIONS ................................... 6
`
`A.
`
`B.
`
`Summary Of Challenged Claims .......................................................... 6
`
`Broadest Reasonable Interpretations ..................................................... 8
`
`IV. PROPOSED UNPATENTABILITY GROUND NO. 1
`(HTTP DRP ANTICIPATES CLAIMS 6, 7, 9, 11, 12 AND 14) ................. 13
`
`V.
`
`PROPOSED UNPATENTABILITY GROUND NO. 2
`(MATTIS ANTICIPATES CLAIMS 6, 7, AND 9) ...................................... 16
`
`VI. PROPOSED UNPATENTABILITY GROUND NO. 3
`(YOHE ANTICIPATES CLAIMS 6 AND 7) ............................................... 17
`
`VII. PROPOSED GROUND FOR UNPATENTABILITY NO. 4
`(ALL CLAIMS OBVIOUS OVER MATTIS AND HTTP DRP) ................ 18
`
`A. Obviousness: Level Of Skill In The Art ............................................ 19
`
`B. Obviousness: Arguable Differences From Some Claims .................. 21
`
`C. Obviousness: Objective Indicia .......................................................... 22
`
`D. Obviousness: Reasons To Combine Mattis and HTTP DRP ............. 23
`
`E.
`
`This Combination Of HTTP DRP And Mattis Teaches Each
`Combination Claimed in Claims 6, 7, 9, 11, 12 and 14 ...................... 26
`
`VIII. PROPOSED GROUND FOR UNPATENTABILITY NO. 5
`(CLAIMS 6, 7, AND 9 OBVIOUS OVER HTTP DRP,
`MATTIS, YOHE AND ADMITTED ART) ................................................. 27
`
`IX. CONCLUSION .............................................................................................. 27
`
`
`
`
`
`i
`
`
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`FILED VIA PRPS ON: January 11, 2013
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`TABLE OF AUTHORITIES
`
`Page
`
`Cases
`In re Epstein,
`32 F.3d 1559 (Fed. Cir. 1994) ....................................................................... 20, 26
`
`In re Fox,
`471 F.2d 1405 (CCPA 1973) ......................................................................... 20, 26
`
`In re Tiffin,
`448 F.2d 791 (CCPA 1971) .................................................................................. 22
`
`In re Vamco Machine & Tool, Inc.,
`752 F.2d 1564 (Fed. Cir. 1985) ............................................................................ 23
`
`Statutes
`
`35 U.S.C. § 102 .......................................................................................................... 4
`
`35 U.S.C. § 103 .......................................................................................................... 4
`
`35 U.S.C. §§ 311 et seq. ............................................................................................. 1
`
`Regulations
`
`37 C.F.R. § 42.103 ..................................................................................................... 1
`
`37 C.F.R. § 42.104 ..................................................................................................... 1
`
`37 C.F.R. § 42.15 ....................................................................................................... 1
`
`
`
`ii
`
`
`
`FILED VIA PRPS ON: January 11, 2013
`
`Fee: In accordance with 37 C.F.R. §§ 42.15, 42.103, please charge the fee
`
`for Inter Partes Review of $27,200.00 to Deposit Account 02-4550.
`
`Identification of Challenge: Pursuant to 35 U.S.C. §§ 311 et seq., Petitioner
`
`Microsoft Corporation (“Microsoft”) requests inter partes review of claims 6, 7, 9,
`
`11, 12 and 14 of U.S. Patent No. 6,757,717, issued to Proxyconn Inc. Sections I-
`
`VIII infra and Appendix A (Ex. 1001) provide the required statement of the precise
`
`relief requested for each claim challenged, per 37 C.F.R. § 42.104(b).
`
`Standing: Microsoft certifies that this patent is available for inter partes
`
`review and that Microsoft is not barred or estopped from requesting an inter partes
`
`review challenging these claims on the grounds identified in this petition. Although
`
`Microsoft was served more than one year ago with a complaint asserting
`
`infringement of this patent, the normal statutory one-year bar under 35 U.S.C. §
`
`315(b) does not apply here because (1) the Board has already instituted an inter
`
`partes review trial on this patent on a timely first petition filed by Microsoft (Case
`
`No. IPR2012-00026), (2) Microsoft accompanies this second petition with a
`
`motion for joinder under 35 U.S.C. § 315(c), and (3) Proxyconn, the patent owner
`
`of record, has consented to such joinder (Ex. 1012).
`
`Real-Party-in-Interest: Microsoft is the sole real-party-in-interest.
`
`Related Matters: Proxyconn is asserting the ’717 patent against Microsoft
`
`and three Microsoft customers (Dell, HP and Acer) in a suit first filed November 3,
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 1
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`
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`FILED VIA PRPS ON: January 11, 2013
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`2011, now styled, Proxyconn Inc. v. Microsoft Corporation, et al., Case No. SA
`
`CV11-1681 DOC (JPRx) [consolidated with Case Nos. SA CV11-1682 DOC
`
`(JPRx), SA CV11-1683 DOC (JPRx), and SA CV11-1684 DOC (JPRx)], pending
`
`in the U.S. District Court for the Central District of California (“the ’717
`
`Concurrent Litigation”). On September 18, 2012, Microsoft filed a Petition for
`
`Inter Partes Review requesting review of claims 1, 3, 10-12, 14 and 22-24 of U.S.
`
`Patent No. 6,757,717, now styled, Microsoft Corporation v. Proxyconn, Inc., Case
`
`No. IPR2012-00026 (TLG).
`
`Lead and Back-Up Counsel; Service Information:
`
`John D. Vandenberg (Lead Counsel, PTO Reg. No. 31312)
`john.vandenberg@klarquist.com
`Direct: 503-273-2338
`Stephen J. Joncus (Back-up Counsel, PTO Reg. No. 44,809)
`stephen.joncus@klarquist.com
`Direct: 503-473-0910
`Klarquist Sparkman LLP
`121 SW Salmon Street, Suite 1600
`Portland, Oregon 97204
`Tel.: 503-595-5300
`Fax: 503-595-5301
`
`Exhibits: An accompanying Appendix and List of Exhibits submits
`
`petitioner’s Exhibits 1001 –1014 in support of this petition, including the
`
`following:
`
`Ex. 1001: Appendix A (which is a part of this Petition), claim chart
`
`mapping the claims to prior art references HTTP DRP, Mattis and Yohe.
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 2
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`FILED VIA PRPS ON: January 11, 2013
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`Ex. 1002: The ’717 patent with Certificate of Correction.
`
`Ex. 1003: HTTP DRP: Arthur van Hoff, John Giannandrea, Mark Hapner,
`
`Steve Carter, and Milo Medin, “The HTTP Distribution and Replication Protocol,”
`
`W3C Note, http://www.w3.org/TR/NOTE-drp-19970825.html, August 1997
`
`(“HTTP DRP”). HTTP DRP is Section 102(b) prior art.
`
`Ex. 1004: Mattis: Peter Mattis et al., U.S. Patent No. 6,292,880, “Alias-
`
`Free Content-Indexed Object Cache,” issued Sept. 18, 2001 on application filed
`
`Apr. 15, 1998 (“’880” or “Mattis”). Mattis is Section 102(e) prior art. (Its Apr.
`
`15, 1998, application is Ex. 1005, which shows that its content on which this
`
`petition relies was filed with the Patent Office on that date.)
`
`Ex. 1006: Yohe: Thomas Patrick Yohe et al., U.S. Patent No. 5,835,943,
`
`“Apparatus and Method for Increased Data Access in a Network File Oriented
`
`Caching System,” issued Nov. 10, 1998 on an application filed July 3, 1997
`
`(“’943” or “Yohe”). Yohe is Section 102(a) and Section 102(e) prior art. (Its July
`
`3, 1997, application is Ex. 1007, which shows that its specification and claims
`
`were issued as originally filed.)
`
`Ex. 1008: Tim Berners-Lee, “W3C Staff Note on HTTP Distribution and
`
`Replication Protocol Submission,”
`
`http://www.w3.org/Submission/1997/10/Comment.html, Aug. 28, 1997.
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 3
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`FILED VIA PRPS ON: January 11, 2013
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`Ex. 1009: Tim Berners-Lee, “Acknowledged Submissions to W3C,”
`
`http://web.archive.org/web/19980213220701/http:/www13.w3.org/Submission/,
`
`Feb. 12, 1998.
`
`Ex. 1010: Michael A. Goulde, “Network Caching Guide Optimizing Web
`
`Content Delivery”, Patricia Seybold Group for Inktomi Corp., Mar. 1999.
`
`Ex. 1011: Simon Spero, “HTTP-NG Architectural Overview,”
`
`http://www.w3.org/Protocols/HTTP-NG/http-ng-arch.html, 1995.
`
`Ex. 1012: Joint Stipulation Requesting Stay of Case Pending Inter Partes
`
`Review, dated Nov. 2, 2012.
`
`Ex. 1013: Expert declaration of Professor Darrell D. E. Long.
`
`Ex. 1014: Supporting declaration of Sean-Michael Riley.
`
`I.
`
`INTRODUCTION
`Microsoft requests the Board to institute inter partes review on each of the
`
`following claims and unpatentability grounds:
`
`1. HTTP DRP anticipates claims 6, 7, 9, 11, 12 and 14, under 35 U.S.C. §
`
`102.
`
`2. Mattis anticipates claims 6, 7 and 9.
`
`3. Yohe anticipates claims 6 and 7.
`
`4. Mattis and HTTP DRP render obvious claims 6, 7, 9, 11, 12 and 14,
`
`under 35 U.S.C. § 103.
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 4
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`FILED VIA PRPS ON: January 11, 2013
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`5. HTTP DRP and Mattis and Yohe and Admitted Art render obvious
`
`claims 6, 7, and 9.
`
`This petition includes its 22-page Appendix A (Ex. 1001) which maps each
`
`challenged claim to Mattis, HTTP DRP and/or Yohe with specific column/page
`
`and line citations. For each ground, the petition demonstrates at least a reasonable
`
`likelihood that each challenged claim is unpatentable.
`
`The ’717 patent describes an algorithm for reducing the amount of redundant
`
`data transmitted over a network. The algorithm checks for identity between two
`
`sets of data by comparing respective digital fingerprints of that data (e.g., MD5
`
`digests)—similar to checking two human fingerprints to determine if they were
`
`taken from the same person. As explained below and in Ex. 1001, the references
`
`already described that algorithm.
`
`II.
`
`’717 PATENT (EX. 1002)
`
`Summary of the Invention: The patent describes its basic idea as follows:
`
`If a sender/computer in a network is required to send data to another
`receiver/computer, and the receiver/computer has data with the same
`digital digest as that of the data to be sent, it can be assumed with
`sufficient probability for most practical applications that the
`receiver/computer has data which is exactly the same as the data to be
`sent. Then, the receiver/computer can use the data immediately
`without its actual transfer through the network. In the present
`invention, this idea is used in a variety of ways. (’717, 2:17-25).
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 5
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`FILED VIA PRPS ON: January 11, 2013
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`The term “digital digest” is discussed below; but it includes a (prior art) 128-
`
`bit MD5 digest.
`
`Admitted Art: The ’717 patent depicts in “Fig. 1 (PRIOR ART)” and “Fig.
`
`2 (PRIOR ART),” and describes at 1:18-60, prior art techniques for caching data
`
`received over a network for later reuse.
`
`Cited Art: Neither Mattis nor HTTP DRP were cited in the original
`
`prosecution. Yohe was cited but not relied on or discussed.
`
`III. CHALLENGED CLAIMS AND THEIR
`BROADEST REASONABLE INTERPRETATIONS
`A.
`
`Summary Of Challenged Claims
`
`This petition challenges two independent claims, the first being claim 6:
`
`6. A system for data access in a packet-switched network,
`comprising:
`
`a gateway including an operating unit, a memory and a
`processor connected to said packet-switched network in such a
`way that network packets sent between at least two other
`computers pass through it;
`
`a caching computer connected to said gateway through a fast
`
`local network, wherein said caching computer includes an
`operating unit, a first memory, a permanent storage memory and a
`processor;
`
`said caching computer further including a network cache
`memory in its permanent storage memory, means for a calculating
`digital digest and means for comparison between a digital digest on
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 6
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`FILED VIA PRPS ON: January 11, 2013
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`data in its network cache memory and a digital digest received
`from said packet-switched network through said gateway.
`(’717, claim 6 (as corrected)).
`
`Claim 6 recites a caching computer having a network cache memory in its
`
`permanent storage, which caching computer has a means for calculating a “digital
`
`digest” and a means for comparing a digital digest received over the network, via a
`
`gateway, to a digital digest on data in its network cache memory. Both HTTP DRP
`
`and Mattis disclose such a caching computer and system.
`
`The second challenged independent claim is claim 11:
`
`11. A method performed by a sender/computer in a packet-
`switched network for increasing data access, said sender/computer
`including an operating unit, a first memory, a permanent storage
`memory and a processor and said sender/computer being operative
`to transmit data to a receiver/computer, the method comprising the
`steps of:
`creating and transmitting a digital digest of said data from said
`sender/computer to said receiver/computer;
`receiving a response signal from said receiver/computer at said
`sender/computer, said response signal containing a positive, partial
`or negative indication signal for said digital digest, and
`if a negative indication signal is received, transmitting said data
`from said sender/computer to said receiver/computer.
`
`Claim 11 recites a sender computer computing a digital digest on data and
`
`sending that digital digest to a receiver computer. The sender then receives a
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 7
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`FILED VIA PRPS ON: January 11, 2013
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`negative, positive or partial response signal and, if the response is negative, the
`
`sender sends the data to the receiver. HTTP DRP discloses the exact same method.
`
`Broadest Reasonable Interpretations
`
`B.
`Petitioner below proposes the broadest reasonable interpretation of certain
`
`claim language, as understood by one of ordinary skill in the art in 1998-99, in
`
`light of the specification (“BRI”). (Nothing herein addresses the correct claim
`
`construction in a judicial litigation context.) Otherwise, the claim language should
`
`be given its plain meaning. Where Petitioner proposes a construction different
`
`than that of the Board in its Decision on Request for Inter Partes Review, IPR2012-
`
`00026, Paper 17, dated December 21, 2012 (“Decision”) this petition demonstrates
`
`unpatentability under each construction. Where Petitioner proposes that claim
`
`language has no patentable weight, this petition demonstrates unpatentability even
`
`if the language has weight.
`
` “a caching computer” (claims 6, 7 and 9): any computer(s) (and
`
`connected storage devices) capable of caching or otherwise storing data for later
`
`retrieval. The “a” caching computer is not limited to a single machine.
`
`“operating unit” (all claims): The Decision gives this term its plain
`
`meaning. (Decision, 14-15). The patent does not explain “operating unit.” As
`
`indefiniteness is not an option here, Petitioner proposes that the BRI of this term
`
`encompasses anything found in a computer that is used in its operation.
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 8
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`FILED VIA PRPS ON: January 11, 2013
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`“network cache memory in its permanent storage memory” (claims 6, 7
`
`and 9): The Decision gives “network cache memory” its plain meaning.
`
`(Decision, 15). Petitioner proposes this BRI: a logical part of memory or storage
`
`[which has been reserved for storing only copies of data received from the
`
`network]. The bracketed portion is part of this limitation but has no patentable
`
`weight when comparing the claim against the prior art. The intended source of
`
`data to be stored does not change the structure or capability of the memory. It is a
`
`mere intended use with no structural significance.
`
`“data” (all claims): The Decision construes this as “a file or range of octets
`
`in a file, a range of frames in a video stream or RAM-based range of octets, a
`
`transport level network packet, or the like.” Col. 2, ll. 5-8.” (Decision, 12).
`
`“digital digest” / “digital digest on data” (claims 6, 7 and 9): The
`
`Decision construes “digital digest” as follows:
`
`“a fixed-size binary value calculated from arbitrary-size binary
`data in such a way that it depends only on the contents of the data
`and the low probability that two different data or objects have the
`same digital digest.” Col. 2, ll. 9-13. The patent further defines the
`term “digital digest” as referring to the known MD5 algorithm, but
`states that other algorithms may be used. For example, a digital
`digest may be calculated according to the CRC algorithm, or by
`applying the CRC algorithm to different subsets or different
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 9
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`FILED VIA PRPS ON: January 11, 2013
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`recordings of data, or by consecutively applying CRC and MD5.
`Col. 6, ll. 24-36.” (Decision, 13).
`
`Petitioner applies this interpretation herein, without waiving its position in
`
`its first petition that the patent contradicts itself by asserting that its “digital digest”
`
`has a similarity check property, i.e., that two digital digests being “substantially
`
`similar” indicates that their underlying data also is substantially similar (e.g., ’717,
`
`4:46-51, 4:65-67, 8:28-31, 8:34-37, 14:10-12)—something neither an MD5 nor
`
`CRC value (nor any other digital fingerprint identified in the patent) has.
`
`“means for calculating a digital digest” (claims 6, 7 and 9): In view of the
`
`Decision’s discussion of a similar term (“means for creating a digital digest”)
`
`(Decision, 15), and as unpatentability under Section 112 is not an option here,
`
`Petitioner proposes that this means-plus-function element encompasses any device
`
`capable of calculating a “digital digest” on data.
`
`“means for comparison between a digital digest on data in its network
`
`cache memory and a digital digest received from said packet-switched
`
`network through said gateway” (claims 6, 7 and 9): The Decision construed
`
`similar language (“means for comparison between digital digests”) “as any general
`
`purpose computer.” (Decision, 15-16). As unpatentability under Section 112 is
`
`not an option here, Petitioner accepts this same interpretation for purposes of this
`
`second petition.
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 10
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`FILED VIA PRPS ON: January 11, 2013
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`“means for storing said calculated digital digest in said permanent
`
`storage memory” (claim 9): The Decision construed similar language (“means
`
`for storing said created digital digest in its first or permanent memory”),
`
`apparently, as “any general purpose computer.” (Decision, 16). As unpatentability
`
`under Section 112 is not an option here, Petitioner accepts this same interpretation
`
`for purposes of this second petition.
`
`“a gateway including . . . connected to said packet-switched network in
`
`such a way that network packets sent between at least two other computers
`
`pass through it”; [a caching computer] “connected to said gateway through a
`
`fast local network” (claims 6, 7 and 9): A “gateway” includes network proxies
`
`and routers. (’717, 2:14-15 (“The term ‘gateway’ as used herein also includes
`
`network proxies and routers.”)) Per dependent claim 8 (“said caching computer is
`
`integrally formed with said gateway”), the caching computer and gateway may be
`
`(but need not be) integrally formed. Thus, the gateway and caching computer may
`
`be the same single unit, such that the memory, operating unit and processor of the
`
`caching computer is also the memory, operating unit and processor of the gateway.
`
`The “fast local network” includes an Ethernet connection (’717, 8:63), but also
`
`includes an internal computer bus when the caching computer and gateway are
`
`integrally formed (i.e., the same unit).
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 11
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`FILED VIA PRPS ON: January 11, 2013
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`“negative indication signal” (claims 11, 12, 14): any indication (e.g., “the
`
`absence of a signal”) treated as a request that a sender send the data to a receiver.
`
`(See ’717, 8:1-10). The Decision accepted that a negative signal may be the
`
`absence of a signal. (Decision, 14).
`
`“positive, partial or negative indication signal” (claims 11, 12, 14): The
`
`Decision construed these claims as requiring the issuance of all three alternative
`
`signals as required. (Decision, 14). Petitioner disagrees for the reasons stated in
`
`its pending motion for rehearing in IPR2012-00026. Nevertheless, this petition
`
`applies the Decision’s interpretation. A “partial” indication signal’s BRI is any
`
`indication treated as a request that a sender send to the receiver a “difference”
`
`between two data items. (’717, Fig. 9). A “positive” indication signal is any
`
`indication treated as not requesting either the data or a difference. (Id.)
`
`“a sender/computer”; “a receiver/computer” (claims 11, 12, 14): The
`
`Decision stated “We construe these terms as a computer that sends or receives
`
`data, respectively. We agree with Petitioner that a sender/computer can include
`
`multiple devices and that it encompasses intermediaries.” (Decision, 14).
`
`“receiving a response signal from said receiver/computer … containing
`
`a positive, partial or negative indication signal for said digital digest” (claims
`
`11, 12, 14): plain meaning, but “positive, partial” has no patentable weight, as
`
`explained in the first petition, but not accepted in the Decision.
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 12
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`FILED VIA PRPS ON: January 11, 2013
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`“if a negative indication signal is received, transmitting said data from
`
`said sender/computer to said receiver/computer” (claims 11, 12, 14): plain
`
`meaning, but no patentable weight, as explained in the first petition, but not
`
`accepted in the Decision. (Decision, 23-24).
`
`“when a plurality of data objects is to be sent, a digital digest is sent for
`
`each of said data objects and a response signal is sent containing a separate
`
`indication signal for each of said data objects” (claim 14): plain meaning, but
`
`no patentable weight, as explained in the first petition, but not accepted in the
`
`Decision.
`
`IV. PROPOSED UNPATENTABILITY GROUND NO. 1
`(HTTP DRP ANTICIPATES CLAIMS 6, 7, 9, 11, 12 AND 14)
`
`Claims 6, 7 and 9: HTTP DRP (Distribution and Replication Protocol) (Ex.
`
`1003) was publicly proposed by industry leaders, including Sun Microsystems,
`
`Netscape and Novell, in 1997 as a supplement to the standard HTTP web
`
`communication protocol. (See Exs. 1008, 1009). HTTP DRP provides
`
`“functionality that can be deployed anywhere where HTTP is available today” (Ex.
`
`1003, 2:22) and is “compatible with existing HTTP servers and proxies” (id.,
`
`2:21). HTTP DRP therefore applies to standard configurations using forward
`
`proxies (on a client’s local network) and/or reverse proxies (on an origin server’s
`
`local network). (See Ex. 1010, 14 (“user’s corporate LAN”), 16-18, 20-21, 25, 40;
`
`Ex. 1011 (cited by Ex. 1003), 6 (“the proxy server will usually be on the same
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 13
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`FILED VIA PRPS ON: January 11, 2013
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`network as the client”)). As shown, element by element, in the claim chart of Ex.
`
`1001, each HTTP DRP client computer and HTTP server has all the functionality
`
`of the caching computer of claim 6 and its dependent claims 7 and 9.
`
`This supplement to the HTTP communication protocol is based on MD5
`
`digests of files and other web content. (Ex. 1001, 1:3-2:5, 6:9-11, 10:3-7, 11:2-8,
`
`12:3-12). HTTP DRP communications requesting files or sending files identify
`
`those files by their name and by their MD5-digest “content identifier” calculated
`
`on the content of that file. (Id.) Each client computer and each HTTP server
`
`computer stores files in its disk file cache, uses MD5 digests to identify that cached
`
`content, and calculates MD5 digests on content. (Id.) Each client and HTTP
`
`server compares MD5 digests received over the network to MD5 digests it
`
`previously stored in its network cache memory. (Id.) For example, an HTTP DRP
`
`client requests a file by identifying its MD5 digest; the proxy caching server
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`intercepts that request and compares that received MD5 digest to the MD5 digests
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`it has cached (along with their associated cached files); and if a match is found the
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`proxy caching server returns the file to the client without downloading it again
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`from the origin server. (Id.) If there is no match, the proxy caching server
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`forwards the request to the origin server which then performs the same HTTP DRP
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`MD5-digest-comparison operation, and response to the client. (Exs. 1001, 1003,
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`1013).
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`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 14
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`FILED VIA PRPS ON: January 11, 2013
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`Claims 11, 12 and 14: As shown, element by element, in the claim chart of
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`Ex. 1001, this HTTP DRP MD5-digest based communication protocol also
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`discloses each step recited in claims 11, 12 and 14 of the ’717 patent.
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`HTTP DRP discloses that client computers receive MD5 digests of network
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`available files and respond thereto with “negative,” “positive” or “partial”
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`indications, as those terms are used in these ’717 patent claims. (Ex. 1001, 15:8-
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`13, 16:10-14, 17:5-18:5, 18:11-19:14, 20:8-14). Specifically, the client receives
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`from the server an “index file” identifying multiple other files by their MD5 digest
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`identifiers. (Id.) The client compares the received MD5 digests to those MD5
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`digests it has stored in its cache file for the files in cache. (Id.) When two MD5
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`digests match, then the client uses its local copy of the file (constituting a
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`“positive” indication signal). (Id.) When there is no match, the client sends a GET
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`request to the HTTP server requesting (by name and MD5-digest identifier) the
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`underlying file (a “negative” indication signal). (Id.) Either the proxy server or
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`HTTP server replies to that request by transmitting the requested file having that
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`MD5-digest identifier. (Id.) In addition, if the digests do not match but the client
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`has an MD5 digest for another version of the file in question, the client sends a
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`“differential GET” request (a “partial” indication signal) identifying both MD5
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`digest values (the one stored at the client and the one received in the new index
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`file). (Id.) The HTTP server or proxy cache then calculates and transmits to the
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`Page 15
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`FILED VIA PRPS ON: January 11, 2013
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`client the differences between the two versions of the file, upon which the client
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`reconstructs the updated file. (Exs. 1001, 1003, 1013).
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`V.
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`PROPOSED UNPATENTABILITY GROUND NO. 2
`(MATTIS ANTICIPATES CLAIMS 6, 7, AND 9)
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`Mattis (Exs. 1004, 1005) discloses an MD5-digest based cache file system.
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`It discloses a web proxy caching computer with a network cache memory in its
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`permanent storage memory, capable of storing “terabytes of information, and
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`billions of objects” (Ex. 1004, 37:59-60). As shown, element by element, in Ex.
`
`1001, this prior art MD5-digest based cache file system discloses each element of
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`claims 6, 7 and 9 of the ’717 patent. (Ex. 1001, 2:6-14, 6:12-7:3, 7:10-12, 10:7-12,
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`11:9-12, 12:12-13:14).
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`This caching computer calculates an MD5 digest on each file or other data
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`object in its network cache memory. (Id.) It also compares a calculated MD5
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`digest to another MD5 digest. (Id.) Mattis discloses various sources for this
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`second MD5 digest. (Id.) First, Mattis discloses deriving this second MD5 digest
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`from a communication received either from a client (e.g., a request for an object
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`having a certain name) or received from an origin server (e.g., transmitting a new
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`file to the web proxy caching computer). (Id.) In the former case, the web proxy
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`cache uses the object name included in the client’s request, to look up in its proxy
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`cache an MD5 digest value (object key) previously calculated as a file-system
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`index for an object with the same name. (Id.) In the latter case, the web proxy
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`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 16
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`FILED VIA PRPS ON: January 11, 2013
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`cache calculates the second MD5 digest from the contents of the newly received
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`file, and then looks for a duplicate digest value already stored in its cache. (Id.)
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`But, in addition, Mattis discloses that this second object MD5 digest value, used in
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`its digest-comparison operation, may be directly received over the network, in a
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`client’s request for an object. (Id.) (This would be the case, e.g., if the client
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`implemented the HTTP DRP protocol.)
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`Whether the second MD5 digest value is obtained from the network
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`indirectly or directly, as described above, the Mattis caching computer uses its
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`same digest-comparison operation, described above. (Exs. 1001, 1004, 1013).
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`VI. PROPOSED UNPATENTABILITY GROUND NO. 3
`(YOHE ANTICIPATES CLAIMS 6 AND 7)
`
`As shown element by element in Ex. 1001, Yohe (Exs. 1006, 1007)
`
`anticipates these claims. (Ex. 1001, 2:14-3:6, 6:6-9, 7:13-14, 10:12-14, 11:13-
`
`12:3, 13:15-14:6, 14:12-14). Yohe’s cache verifying computer and file server
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`computer, networked together and to communication server 16 (serving as a
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`gateway) via LAN link 20, is designed to calculate MD5 digests on objects in its
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`disk storage cache and compare those calculated MD5 digests to MD5 digest
`
`values received over the network, from a client 12, via the gateway. (Exs. 1001,
`
`1006).
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`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 17
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`FILED VIA PRPS ON: January 11, 2013
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`VII. PROPOSED GROUND FOR UNPATENTABILITY NO. 4
`(ALL CLAIMS OBVIOUS OVER MATTIS AND HTTP DRP)
`
`As explained by Professor Long (Ex. 1013) and demonstrated in the
`
`incorporated claim chart (Ex. 1001), the combination of the MD5-digest based
`
`HTTP DRP communication protocol with the Mattis MD5-digest based cache file
`
`system is a natural combination. When these complementary references are
`
`combined, clients, forward and reverse web proxies, and origin web servers, are
`
`equipped to calculate, store and compare MD5-digest content identifiers, as
`
`described in Mattis. And, they also use those same MD5-digest content identifiers
`
`in HTTP DRP GET requests, differential GET requests, and replies thereto, as
`
`described in HTTP DRP. This natural combination of these complementary
`
`references provides all of the functionality recited in these six challenged claims
`
`and renders them unpatentable for obviousness.
`
`Claims 6, 7 and 9: As described above, the Mattis web proxy caching
`
`computer and gateway, with its MD5-digest based cache file system, calculates
`
`MD5 digests to act as content identifiers, and compares such MD5 identifiers both
`
`to respond to client requests for objects and also to delete redundant copies of
`
`objects in its disk cache. And, Mattis expressly contemplates that some client
`
`object requests will identify the object by its MD5 digest. HTTP DRP discloses
`
`just such object requests identifying the requested object by its MD5 digest
`
`identifier. Therefore, a client equipped with the HTTP DRP protocol connected to
`
`Second Petition for Inter Partes Review of U.S. Patent No. 6,757,717
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`Page 18
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`FILED VIA PRPS ON: January 11, 2013
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`a forward proxy caching computer equipped with a Mattis file system and HTTP
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`DRP protocol discloses the entirety of claims 6, 7 and 9 of the ’717 patent. As
`
`explained below, a