UNITED STATES PATENT AND TRADEMARK OFFICE
`
`
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`_____________________
`
`Avi Networks, Inc.,
`Petitioner
`v.
`Citrix Systems, Inc.,
`Patent Owner.
`
`_____________________
`
`Case No. Unassigned
`
`U.S. Patent No. 9,148,493
`
`_____________________
`
`Petition for Inter Partes Review of U.S. Patent No. 9,148,493
`
`
`
`
`
`
`
`
`
`Mail Stop PATENT BOARD
`Patent Trial and Appeal Board
`U.S. Patent and Trademark Office
`P.O. Box 1450
`Alexandria, VA 22313-1450
`
`
`
`
`

`

`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`
`TABLE OF CONTENTS
`
`Page
`INTRODUCTION ........................................................................................... 1
`I.
`II. MANDATORY NOTICES ............................................................................. 1
`A.
`Real Parties-in-Interest 37 C.F.R. § 42.8(b)(1) ..................................... 1
`B.
`Related Matters Under 37 C.F.R. § 42.8(b)(2) ..................................... 1
`1.
`Current Litigation ........................................................................ 1
`2.
`Administrative proceedings ........................................................ 2
`Lead and Back-Up Counsel ................................................................... 2
`C.
`Service of Information Under 37 C.F.R. § 42.8(b)(4) .......................... 3
`D.
`PAYMENT OF FEES ..................................................................................... 3
`III.
`IV. REQUIREMENTS OF INTER PARTES REVIEW ........................................ 3
`A.
`Standing ................................................................................................. 4
`B.
`Identification of Challenge and Relief Requested ................................ 4
`C.
`How the Challenged Claims are to be Construed Under 37
`C.F.R. § 42.104(b)(3) ............................................................................ 7
`D. How the Challenged Claims are Unpatentable Under 37 C.F.R.
`§ 42.104(b)(4) ........................................................................................ 8
`Supporting Evidence Under 37 C.F.R. § 42.104(b)(5) ......................... 8
`E.
`THRESHOLD REQUIREMENT FOR INTER PARTES REVIEW ............. 8
`V.
`VI. LEVEL OF SKILL IN THE ART ................................................................... 9
`A.
`Person of Ordinary Skill ........................................................................ 9
`B.
`Background in the Relevant Art ............................................................ 9
`1.
`The Protocol Stack ...................................................................... 9
`2.
`Proxies .......................................................................................12
`3.
`Persistent Connections ..............................................................13
`
`i
`
`

`

`
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`TABLE OF CONTENTS
`(continued)
`
`Page
`
`
`
`4.
`Connection Pooling ...................................................................14
`VII. OVERVIEW OF THE ’493 PATENT ..........................................................14
`A.
`Summary of the Alleged Invention of the ’493 Patent .......................14
`B.
`Summary of the Prosecution History of the ’493 Patent ....................18
`C.
`Proposed Claim Constructions ............................................................19
`VIII. DETAILED CHALLENGE ..........................................................................22
`A. Ground 1: Squid Anticipates Claims 1–5, 7, 9–13, 15, and 17–
`20 under § 102 .....................................................................................23
`1.
`Overview of Squid ....................................................................23
`2.
`Squid is a Printed Publication ...................................................26
`3.
`Squid 2.0 Source Code ..............................................................31
`4.
`Analysis of Unpatentability ......................................................38
`Ground 2: Squid Renders Claims 1–5, 7, 9–13, 15, and 17–20
`obvious under § 103 ............................................................................58
`Ground 3: Squid in light of RFC 2068 Renders Claims 8 and
`16 obvious under § 103 .......................................................................59
`D. Ground 4: Susai in light of Squid Renders Claims 1–5, 7, 9–13,
`15, and 17–20 obvious under § 103 ....................................................62
`Ground 5: Susai over RFC 2068 Renders Claims 1–5, 7–13,
`and 15–20 obvious under § 103 ..........................................................77
`IX. CONCLUSION ..............................................................................................80
`X.
`CERTIFICATE OF WORD COUNT ...........................................................81
`
`
`
`B.
`
`C.
`
`E.
`
`
`
`ii
`
`

`

`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`
`TABLE OF AUTHORITIES
`
`Page(s)
`
`Cases
`Baron v. Bausch & Lomb Inc.,
`No. CIV-79-2C, 1992 WL 46979 (W.D.N.Y. Feb. 25, 1992) ............................ 30
`Citrix Systems, Inc. v. Avi Networks, Inc.,
`No. 1:17-cv-1843 (D. Del.) ................................................................................... 1
`Dow Jones & Co. v. Ablaise Ltd.,
`632 F. Supp. 2d 23 (D.D.C. 2009), vacated on jurisdictional
`grounds, 606 F.3d 1338 (Fed. Cir. 2010) ..................................................... 28, 30
`Eolas Techs. Inc. v. Adobe Systems, Inc.,
`No. 6:09-cv-446, 2012 WL 12896524 (E.D. Tex. July 19, 2012)...................... 30
`In re Hall,
`781 F.2d 897 (Fed. Cir. 1986) ............................................................................ 26
`HTC Corp. v. Cellular Communications Equip., LLC,
`877 F.3d 1361 (Fed. Cir. 2017) ............................................................................ 7
`Inpro II Licensing, S.A.R.L. v. T-Mobile,
`450 F.3d 1350 (Fed. Cir. 2006) .......................................................................... 21
`In re Klopfenstein,
`380 F.3d 1345 (Fed. Cir. 2004) .......................................................................... 27
`SciMed Life Sys., Inc. v. Davanced Cardivascular Sys., Inc.,
`242 F.3d 1337 (Fed. Cir. 2001) .......................................................................... 21
`SRI Int’l, Inc. v. Internet Sec. Sys., Inc.,
`511 F.3d 1186 (Fed. Cir. 2008) .......................................................................... 27
`Suffolk Techs., LLC v. AOL Inc.,
`752 F.3d 1358 (Fed. Cir. 2014) .......................................................................... 27
`
`iii
`
`

`

`
`
`Petition for Inter Partes Review
`of U.S. Patent No. RE45,386
`
`TABLE OF AUTHORITIES
`(continued)
`
`Page(s)
`
`Voter Verified, Inc. v. Premier Election Solutions, Inc.,
`698 F.3d 1374 (Fed. Cir. 2012) .................................................................... 27, 29
`Statutes
`35 U.S.C. § 102 .......................................................................................................... 6
`35 U.S.C. § 311 ........................................................................................................ 26
`Regulations
`37 C.F.R. § 42.100(b) ................................................................................................ 7
`83 F.R. 51358 (2018) ................................................................................................. 7
`
`iv
`
`

`

`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`
`TABLE OF EXHIBITS
`
`Exhibit
`Number Document
`1001
`U.S. Patent No. 9,148,393 (“the ’493 Patent”)
`1002
`File History for U.S. Patent No. 9,148,393
`1003
`Complaint, Citrix Systems, Inc. v. Avi Networks, Inc., No. 1:17-cv-
`1843 (D. Del.)
`Excerpts of Source Code for Squid Cache version 2.0 (“Squid”)
`
`1004
`
`1005
`
`1006
`
`1007
`1008
`1009
`1010
`
`1011
`
`1012
`
`1013
`1014
`
`1015
`
`1016
`
`1017
`
`1018
`1019
`1020
`
`WO 00/28433 to Susai et al. (“Susai”)
`
`Request for Comments No. 2068, Hypertext Transfer Protocol –
`HTTP/1.1 (“RFC 2068”)
`Declaration of Dr. Kevin Jeffay
`Declaration of Duane Wessels
`Declaration of Alex Rousskov
`Squid Cache Index of Version 1 (http://www.squid-
`cache.org/Versions/v1/1.0/)
`Squid Cache Index of Version 2 (http://www.squid-
`cache.org/Versions/v2/2.0/)
`August 10, 1997 Squid Cache Commit Log (https://github.com/squid-
`cache/squid/commit/603a02fd0546277c038c9ab1bc2481a8d42d707e)
`Squid – The Definitive Guide, Duane Wessels, January 2004
`Squid Web Proxy Cache Web Archive, October 13, 1999
`(http://squid-cache.org)
`Squid Newsgroup Post, Re: [SQU] persistent connection sharing,
`September 14, 2000
`Squid Newsgroup Post, Re: HTTP1.0/HTTP1.1 persistent
`connections, September 25, 2000
`Squid Newsgroup Post, Re: Persistent Connections, December 5,
`1998
`Squid Newsgroup Post, Re: Persistent Connections, March 13, 1999
`Squid Newsgroup Post, Re: Persistent Connections?, July 12, 1999
`Squid Newsgroup Post, Re: Prohibiting persistent connections for
`
`v
`
`

`

`Petition for Inter Partes Review
`of U.S. Patent No. RE45,386
`
`TABLE OF EXHIBITS
`(continued)
`
`Exhibit
`Number Document
`some hosts, August 17, 1998
`Squid Newsgroup Post, Squid 2.0 and cachemgr?, October 8, 1998
`Squid Newsgroup Post, Squid 2.1PATCH1, December 4, 1998
`Squid Newsgroup Post, Squid2.0 loops when using cache_peer,
`October 2, 1998
`
`1021
`1022
`1023
`
`
`
`
`
`
`
`
`
`
`vi
`
`

`

`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`
`INTRODUCTION
`Pursuant to 35 U.S.C. § 311, Avi Networks, Inc. (“Avi” or “Petitioner”)
`
`I.
`
`submits this petition for inter partes review (“IPR”), seeking cancellation of claims
`
`1–5, 7–13, and 15–20 of U.S. Patent No. 9,148,493 (“the ’493 Patent,” Ex. 1001).
`
`This petition demonstrates that there is a reasonable likelihood that Petitioner will
`
`prevail on at least one of the claims challenged in the petition based upon prior art
`
`references that the USPTO did not have before it during prosecution. Claims 1–5,
`
`7–13, and 15–20 should therefore be cancelled as unpatentable under 35 U.S.C.
`
`§§ 102 and 103 over the prior art references identified in this petition.
`
`II. MANDATORY NOTICES
`A. Real Parties-in-Interest 37 C.F.R. § 42.8(b)(1)
`Avi Networks, Inc. (“Avi”) is the real party-in-interest.
`
`B. Related Matters Under 37 C.F.R. § 42.8(b)(2)
`Current Litigation
`1.
`The ’493 Patent is presently the subject of litigation in a suit brought by
`
`Patent-Owner—Citrix Systems, Inc. v. Avi Networks, Inc., No. 1:17-cv-1843 (D.
`
`Del.) (Ex. 1003).
`
`1
`
`

`

`
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`Administrative proceedings
`2.
`Petitioner is concurrently filing one petition for IPR of one other patent
`
`asserted in the Patent-Owner’s litigation against Petitioner: related U.S. Patent No.
`
`8,631,120.
`
`C. Lead and Back-Up Counsel
`Petitioner provides the following designation of counsel:
`
`Lead Counsel
`
`Back-up Counsel
`
`Y. Ernest Hsin
`(Reg. No. 55283)
`Gibson, Dunn & Crutcher LLP
`555 Mission Street
`San Francisco, CA 94105-0921
`Tel: 415-393-8224
`EHsin@gibsondunn.com
`
`Brian Rosenthal
`(pro hac vice motion requested)
`Gibson, Dunn & Crutcher LLP
`200 Park Avenue
`New York, NY 10166-0193
`Tel: 212-35102339
`BARosenthal@gibsondunn.com
`Ryan Iwahashi
`(Reg. No. 63378)
`Gibson, Dunn & Crutcher LLP
`1881 Page Mill Road
`Palo Alto, CA 94304-1211
`Tel: 650-849-5367
`RIwahashi@gibsondunn.com
`
`Petitioner respectfully requests authorization to file a motion for Brian A.
`
`
`
`Rosenthal to appear before the USPTO pro hac vice. Mr. Rosenthal is an
`
`experienced litigating attorney and is currently serving as one of the lead counsels
`
`2
`
`

`

`
`for Petitioner in related matter Citrix Systems, Inc. v. Avi Networks, Inc., No. 1:17-
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`cv-1843 (D. Del.). Mr. Rosenthal has established familiarity with the subject
`
`matter at issue in this proceeding. Petitioner intends to file a motion to appear pro
`
`hac vice under 37 C.F. R. § 42.10. Pursuant to 37 C.F.R. § 42.10(b), a power of
`
`attorney accompanies this Petition.
`
`Service of Information Under 37 C.F.R. § 42.8(b)(4)
`D.
`Service of any documents via hand-delivery may be made at the mailing
`
`address of lead and backup counsel designated above. Petitioner also hereby
`
`consents to electronic service, and service via electronic mail may be made at the
`
`email addresses provided above for the lead and back-up counsel.
`
`III. PAYMENT OF FEES
`Pursuant to 37 C.F.R. §§ 42.103 and 42.15(a), the required fee is being
`
`submitted herewith. The Office is authorized to charge any fee deficiency, or
`
`credit overpayment, to deposit account no. 501408. Any additional fees due in
`
`connection with this petition may be charged to the foregoing account.
`
`IV. REQUIREMENTS OF INTER PARTES REVIEW
`Pursuant to 37 C.F.R. § 42.104, each requirement for inter partes review of
`
`the ’493 Patent is satisfied.
`
`3
`
`

`

`
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`Standing
`A.
`Pursuant to 37 C.F.R. § 42.104(a), Petitioner certifies that the ’493 Patent is
`
`available for IPR and that Petitioner is not barred or estopped from requesting IPR
`
`of the claims on the grounds identified herein. Specifically, Petitioner certifies
`
`that: Petitioner has not filed a civil action challenging the validity of the ’493
`
`Patent; this Petition is filed not more than one year from March 19, 2018, the date
`
`on which the Petitioner was served with the complaint alleging infringement of the
`
`’493 Patent; the estoppel provisions of 35 U.S.C. § 315(e)(1) do not prohibit this
`
`inter partes review; and this Petition is filed after the later of (a) the date that is
`
`nine months after the date of the grant of the ’493 Patent or (b) the termination of
`
`any post-grant review of the ’493 Patent.
`
`Identification of Challenge and Relief Requested
`B.
`Pursuant to 37 C.F.R. § 42.104(b), Petitioner requests that the Board institute
`
`inter partes review of claims 1–5, 7–13, and 15–20 of the ’493 Patent on one or
`
`more grounds under pre-AIA 35 U.S.C. §§ 102 and/or 103. The precise relief
`
`requested by Petitioner is that claims 1–5, 7–13, and 15–20 be cancelled in view of
`
`the following prior art references:
`
`4
`
`

`

`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`Filing/
`Priority Date
`N/A
`
`Date of
`Publication
`October 2, 1998
`
`Exhibit No.
`Ex. 1004
`
`November 10, 1999 May 18, 2000
`
`Ex. 1005
`
`N/A
`
`January 1997
`
`Ex. 1006
`
`
`
`Patent/
`Publication
`Source Code for Squid
`Cache version 2.0
`(“Squid”)
`WO 00/28433 to Susai
`et al. (“Susai”)
`Request for Comments
`No. 2068 (“RFC 2068”)
`
`
`The ’493 Patent is a U.S. Patent resulting from application No. 14/107,971
`
`filed December 16, 2013, which is a continuation of application No. 12/855,260,
`
`filed August 12, 2010, now U.S. Patent No. 8,631,120, which is a continuation of
`
`application No. 09/690,437, filed October 18, 2000, now U.S. Patent No.
`
`7,801,978. Therefore, claims 1–5, 7–13, and 15–20 of the ’493 Patent are entitled
`
`to claim priority no earlier than October 18, 2000. For purposes of this petition,
`
`Petitioner assumes that the claims of the ’493 Patent are in fact entitled to a priority
`
`date of October 18, 2000.
`
`5
`
`

`

`Accordingly, Squid and RFC 2068 qualify as prior art to the ’493 Patent at
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`
`
`least under 35 U.S.C. § 102(b),1 and Susai qualifies s prior art under at least 35
`
`U.S.C. § 102(a).
`
`Squid and RFC 2068 were not cited during the prosecution of the ’493
`
`Patent. Although Susai was considered by the examiner, the examiner did not have
`
`the benefit of Squid or RFC 2068 and therefore did not consider the combination
`
`of Susai and Squid or Susai and RFC. In the instant inter partes review, Petitioner
`
`applies the above references and asserts the following grounds of rejection under
`
`35 U.S.C. §§ 102 and 103:
`
`Claims
`1–5, 7, 9–13, 15, and
`17–20
`1–5, 7, 9–13, 15, and
`17–20
`8, 16
`
`Ground
`1
`
`2
`
`3
`
`4
`
`5
`
`Proposed Statutory Rejections
`for the ’493 Patent
`Anticipated by 35 U.S.C. § 102 by Squid
`
`Obvious under 35 U.S.C. § 103 over Squid
`Obvious under 35 U.S.C. § 103 over Squid in
`view of RFC 2068
`Obvious under 35 U.S.C. § 103 over Susai in
`1–5, 7, 9–13, 15, and
`view of Squid
`17–20
`1–5, 7–13, and 15–20 Obvious under 35 U.S.C. § 103 over Susai in
`view of RFC 2068
`
`
` 1 Unless specifically noted, all references to Title 35 of the United States Code
`refer to code pre-America Invents Act. See, e.g., 35 U.S.C. § 102 (2011).
`
`6
`
`

`

`
`
`
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`C. How the Challenged Claims are to be Construed Under 37 C.F.R.
`§ 42.104(b)(3)
`A claim subject to inter partes review “shall be construed using the same
`
`claim construction standard that would be used to construe a claim in a civil action
`
`under 3 U.S.C. § 282(b), including construing the claim in accordance with the
`
`ordinary and customary meaning of such claim as understood by one of ordinary
`
`skill in the art and the prosecution history pertaining to the patent.” 37 C.F.R.
`
`§ 42.100(b) (November 13, 2018); 83 F.R. 51358 (2018). Petitioner respectfully
`
`proposes that the term “transport layer connection” in all claims be construed
`
`under this standard to mean “connection at the transport layer between two devices
`
`such that there is no application layer connection between those two devices.”
`
`Petitioner does not believe any other claims constructions have an impact on the
`
`invalidity analyses set forth herein. See HTC Corp. v. Cellular Communications
`
`Equip., LLC, 877 F.3d 1361, 1367-68 (Fed. Cir. 2017) (affirming the Board absent
`
`an express construction of a term). A more detailed discussion supporting this
`
`construction is provided below.
`
`7
`
`

`

`
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`D. How the Challenged Claims are Unpatentable Under 37 C.F.R. §
`42.104(b)(4)
`An explanation of how claims 1–5, 7, 9–13, 15, and 17–20 of the ’493 Patent
`
`are unpatentable under the statutory grounds identified above, including the
`
`identification of where each element of the claim is found in the prior art patents or
`
`printed publications, is provided below.
`
`Supporting Evidence Under 37 C.F.R. § 42.104(b)(5)
`E.
`The exhibit numbers of the supporting evidence relied upon and the
`
`relevance of the evidence to the challenged claims, including an identification of
`
`specific portions of the evidence that support the challenge, are provided below. A
`
`list of exhibits identifying the exhibits is also included in this petition. The
`
`technical information and grounds for rejection explained in the petition are further
`
`supported by the Expert Declaration of Dr. Kevin Jeffay, attached as Exhibit 1007
`
`and the Declarations of Duane Wessels and Alex Rousskov attached as Exhibits
`
`1008 and 1009, respectively.
`
`A List of Exhibits is included in this paper pursuant to 37 C.F.R. § 42.63(e).
`
`V. THRESHOLD REQUIREMENT FOR INTER PARTES REVIEW
`Under 35 U.S.C. § 314(a), institution of inter partes review requires “a
`
`reasonable likelihood that the petitioner would prevail with respect to at least one
`
`8
`
`

`

`
`of the claims challenged in the petition.” This petition meets this threshold for
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`each of the asserted grounds of unpatentability.
`
`VI. LEVEL OF SKILL IN THE ART
`Person of Ordinary Skill
`A.
`A person of ordinary skill in the art (“POSITA”) in October 18, 2000 would
`
`have a Bachelor’s degree in Computer Science, Computer Engineering, Electrical
`
`Engineering, or an equivalent discipline, and at least one year’s worth of
`
`experience developing client/server systems and/or application layer network
`
`communication protocols. In the alternative, a POSITA could have two or more
`
`years of work experience in computer networking and in the development of
`
`client-server systems in lieu of the education requirements. Ex. 1007, ¶ 21.
`
`Background in the Relevant Art
`B.
`All concepts in this section were well known and widely used by POSITAs at
`
`least as of October 18, 2000.
`
`The Protocol Stack
`1.
`In the same way people that speak to each other must use a common
`
`language, computers that communicate must use a common protocol for
`
`transferring data to ensure they understand each other. In a single network
`
`9
`
`

`

`
`communication, there is actually a “stack” of protocols layered on top of each
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`other so the different components of the network can communicate with each
`
`other, e.g., routers versus clients/servers. Ex. 1007, ¶¶ 44-45. Although there are
`
`many different standardized protocols, the most commonly used combination of
`
`protocols on the internet is the hypertext transfer protocol (“HTTP”) running on
`
`top of the transmission control protocol (“TCP”). Id., ¶¶ 59, 64.
`
`HTTP is an application layer protocol, which is the highest level protocol in
`
`the stack. This means that the body of the HTTP message is the message that the
`
`sending device wants to send. The HTTP protocol needs to add information in the
`
`form of a header—i.e., additional bits of information appended to the body—to
`
`ensure delivery to the correct destination. The HTTP header includes information,
`
`such as the source, destination, and length of the message. Id., ¶¶ 64.
`
`TCP is a transport layer protocol, which is the next layer in the stack. The
`
`body of the TCP message, which is called a segment, consists of the HTTP header
`
`plus the message. Like HTTP, TCP will also add its own header. The TCP header
`
`includes more specific information about the source and destination of the
`
`message—e.g., specific port numbers. Id., ¶ 61. There are other layers beneath the
`
`transport layer that also add more information in the form of additional headers to
`
`10
`
`

`

`
`the message—e.g., network layer, link layer. These lower layers help route the
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`message to its intended destination through the internet—e.g., through routers and
`
`switches. See id., ¶¶ 46-58. The HTTP and TCP layers, on the other hand, are
`
`typically only touched by the sender and recipient of the message—i.e., the
`
`intermediary stops do not process the HTTP and TCP layers. Id. ¶¶ 71-72. Figure
`
`8 from Dr. Jeffay’s declaration is illustrative of this process:
`
`
`
`For example, if a client sends a request to the server, that request will be the
`
`body of the HTTP message. The HTTP handler on the client will add an HTTP
`
`header and then pass that information onto the TCP handler, which will also add its
`
`own TCP header. When the server receives the request, the TCP handler will
`
`remove the TCP header and pass to the HTTP handler, which will remove the
`
`11
`
`

`

`
`HTTP header and process the request. See id., ¶ 66. The intermediate routers and
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`switches, however, will not touch the TCP and HTTP information.
`
`Proxies
`2.
`Proxy servers, or web caches, were well-known devices as of 2000 that can
`
`respond to requests from clients on behalf of servers. Proxies were used to
`
`alleviate the load on servers and reduce network traffic. See id., ¶ 87. A proxy
`
`may, or may not, keep local copies of requested objects to respond directly to
`
`requests from clients. When a client requests an object via a proxy, it will establish
`
`a network connection (at the HTTP and TCP level) directly with the proxy. If the
`
`proxy needs to get the information with the server, the proxy will establish its own
`
`HTTP and TCP level connections with the server. Id. Figure 10 from Dr. Jeffay’s
`
`depicts this process:
`
`12
`
`

`

`
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`Proxies were well known and widely used in the internet at least as of the
`
`
`
`1990s. Id., ¶ 88.
`
`Persistent Connections
`3.
`The use of persistent connections is another well-known way to improve
`
`network performance. A TCP connection between two devices requires the
`
`communicating devices to first exchange several messages to ensure they are
`
`speaking to the correct device and establish error control. This exchange is called
`
`the connection setup and can increase the response time, especially where the
`
`actual messages being exchanged are relatively short. Id., ¶ 80. To avoid the delay
`
`of multiple connection setups, HTTP may set up a persistent TCP connection that
`
`13
`
`

`

`
`can be reused for multiple HTTP requests. Id., ¶¶ 80-81. This means that a new
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`connection does not have to be setup and torn down for each request.
`
`HTTP/1.1, which was published in RFC 2068 at least as early as January
`
`1997, discloses using persistent connections as the default for all HTTP/1.1
`
`requests. Ex. 1006, § 8.1; Ex. 1007, ¶ 81.
`
`Connection Pooling
`4.
`Connection pooling is another well-known way to improve network
`
`performance, which leverages proxies and persistent connections. Instead of a
`
`client opening and closing connections directly with the server, the client will
`
`communicate with the proxy and the proxy can maintain a “pool” of one or more
`
`persistent connections with the server. These persistent connections in the pool
`
`can be reused by different clients without connection establishment and teardowns.
`
`See Ex. 1001, 4:14-22. This is called “connection pooling.”
`
`VII. OVERVIEW OF THE ’493 PATENT
`Summary of the Alleged Invention of the ’493 Patent
`A.
`The ’493 Patent purports to describe a more efficient system for pooling
`
`network connections at an intermediary device—i.e., proxy, depicted in Figure 2 as
`
`“Interface Unit 202”.
`
`14
`
`

`

`
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`
`
`The concepts of proxies, persistent connection, and connection pooling were
`
`well known as of the earliest priority date for the ’493 Patent, but the ’493 Patent
`
`purports to disclose a system that “more effectively utilize[s] the pooling of
`
`connections between clients and servers over the Internet.” Id., 1:26-28. Figure 3
`
`depicts the known steps of connection pooling from the perspective of the proxy:
`
`15
`
`

`

`
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`
`
`When the proxy receives a request from the client, the proxy will pass that
`
`request to the server, if possible, using a connection that is already open with that
`
`server (steps 302, 304, 306, 310). The proxy will then receive the response from
`
`the server 312 and pass the response along to the client 314. According to the
`
`16
`
`

`

`
`patent, the prior art proxy would then wait until the client closes the connection
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`with the proxy—via a FIN (finish) or RST (reset) command—before adding the
`
`persistent connection between the proxy and the server back into the pool of
`
`available connections 316. See id., 4:56-5:2. The above method of connection
`
`pooling was admittedly known in the art and was disclosed in the Susai reference.
`
`Ex. 1002, 441.
`
`This is where the ‘493 Patent purports to improve on the prior art. Instead of
`
`waiting for the close command from the client, the “present invention” purports to
`
`enable the proxy to reuse the persistent connection as soon as the proxy determines
`
`that the server is done sending the response. See id., 12:25-32. The patent
`
`discloses that the proxy can determine the end of the response using known
`
`properties of the HTTP message header—e.g., the content length parameter or
`
`chunking parameter—to determine when the response from the server is finished,
`
`rather than waiting for a close command from the client. E.g., id., 6:63-65.
`
`The ’493 Patent has two independent claims—Claim 1 and 9. Claim 1 is a
`
`method claim and claim 9 is a system claim. Both are directed to the purported
`
`improved connection pooling system that reuses the pooled connection for a
`
`17
`
`

`

`
`different device “prior to receiving a close command from the first client.” Ex.
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`1001, 17:56-57, 18:49-50.
`
`Summary of the Prosecution History of the ’493 Patent
`B.
`During prosecution of the ’493 Patent, on August 26, 2014, the examiner
`
`rejected all of initial claims under 35 U.S.C. § 102 as anticipated by Susai.2 Ex.
`
`1002, 368-71. On November 26, 2014, the applicant attempted to traverse the
`
`rejection by arguing that Susai did not disclose reusing the pooled connection until
`
`the first client had closed the connection, whereas the claims were directed to a
`
`device that determined when the server completed communicating the response.
`
`Ex. 1002, 441.
`
`On February 25, 2015, however, the examiner maintained his rejection that
`
`the claims were anticipated by Susai. On April 8, 2015, the applicant amended his
`
`claims to require, inter alia, that the pooled connection be reused by another client
`
`“prior to receiving a close command from the first client via the first transport
`
`layer connection between the first client and the device.” Ex. 1002, 469, 475-76
`
`
` 2 Susai is a WO application, but it is identical in substance to the application
`referenced specification of the patent (09/188,709).
`
`18
`
`

`

`
`(“Fig. 5 of Susai . . . shows that the second request of the second client over the
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`transport layer connection is forwarded at flow line 520 after receiving a close
`
`command from the first client at flow line 514.” (emphasis in original)). The
`
`examiner allowed the amended claims on April 28, 2018 and the ’493 Patent
`
`issued on September 29, 2015.
`
`Proposed Claim Constructions
`C.
`The term “transport layer connection” in the claims refers to a “connection at
`
`the transport layer between two devices such that there is no application layer
`
`connection between those two devices.” This construction is consistent with the
`
`plain language of the claims, the specification, and the prosecution history. The
`
`claims recite establishing a “pool of one or more transport layer connections” with
`
`a server and then sending a message “over a [] transport layer connection from the
`
`pool.” Ex. 1001, 17:37–43. Petitioner’s proposed construction is consistent with
`
`that usage of “transport layer connection” in the claims.
`
`The specification makes clear that the “transport layer connections” between
`
`the clients and the intermediate device, and between the intermediate device and
`
`the servers, do not include application layer connections between those devices. In
`
`particular, the specification describes a “novel translation technique” that is used
`
`19
`
`

`

`
`“to seamlessly splice the client and server connections.” Id., 6:31-33. “According
`
`Petition for Inter Partes Review
`of U.S. Patent No. 9,148,493
`
`to this technique, a packet is translated by modifying its sequence number and
`
`acknowledgement number at the TCP protocol level. A significant advantage of
`
`this technique is that no application layer interaction is required.” Id., 6:38-40
`
`(emphasis added). The specification goes on to explain how that novel translation
`
`technique is used in “the present invention” to achieve the claimed connection
`
`multiplexing. E.g., id., 9:31–12:48.
`
`Because no application layer interaction is required by the intermediate
`
`device (and instead all of the manipulation of the sequence and acknowledgement
`
`numbers are done at the TCP layer), there is no application layer connection
`
`between the intermediate device and the clients or between the intermediate device
`
`and the servers. Ex. 1007, ¶ 142. Instead, the only application layer connection is
`
`between the client (which sends the HTTP request), and the server (which receives
`
`and processes the HTTP request, and returns an HTTP response). The
`
`intermediate device is simply not involved at the application layer. Id., ¶¶ 142-43.
`
`The claimed “transport layer connections” should be construed to exclude
`
`application layer connections with the intermediate device, in view of the emphasis
`
`in the specification of the importance of the intermediate device not having an
`
`20
`
`

`

`
`application layer connection