Paper No. 30
`
`
`
`
`
`Trials@uspto.gov
`571-272-7822 Entered: November 13, 2018
`
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`UNIFIED PATENT INC.,
`Petitioner
`
`v.
`
`PLECTRUM LLC,
`Patent Owner
`____________
`
`IPR2017-01430
`Patent 5,978,951
`____________
`
`
`Before KEN B. BARRETT, MIRIAM L. QUINN, and
`SHEILA F. McSHANE, Administrative Patent Judges.
`
`McSHANE, Administrative Patent Judge.
`
`
`
`
`FINAL WRITTEN DECISION
`Inter Partes Review
`35 U.S.C. § 318(a) and 37 C.F.R. § 42.73
`
`
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`IPR2017-01430
`Patent 5,978,951
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`I. INTRODUCTION
`We have jurisdiction to hear this inter partes review under 35 U.S.C.
`§ 6. This Final Written Decision is issued pursuant to 35 U.S.C. § 318(a)
`and 37 C.F.R. § 42.73. For the reasons discussed herein, we determine that
`Petitioner has shown, by a preponderance of the evidence, that claims 8 and
`11 of U.S. Patent No. 5,978,951 (Ex. 1001, “the ’951 patent”) are
`unpatentable and Petitioner has not shown, by a preponderance of the
`evidence, that claims 1–6, 12–14, and 21–24 of the ’951 patent are
`unpatentable.
`
`A. Procedural Background
`Unified Patents Inc. (“Petitioner”) filed a Petition requesting inter
`partes review of claims 1–6, 8, 11–14, and 21–24 (“the challenged claims”)
`of the ’951 patent pursuant to 35 U.S.C. §§ 311–319. Paper 3 (“Pet.”). The
`Declaration of Dr. Srinivasan Seshan (“Seshan Declaration”) in support of
`the Petition was filed. Ex. 1007. Plectrum LLC (“Patent Owner”) filed a
`Preliminary Response to the Petition. Paper 7 (“Prelim. Resp.”). Pursuant
`to 35 U.S.C. § 314(a), on November 14, 2017, we instituted inter partes
`review on the following ground:
`-whether claims 8 and 11 would have been obvious under
`35 U.S.C. § 103(a) in view of Cheriton1 and Jain2.
`See Paper 8 (“Inst. Dec.” or “Dec.”). Subsequent to institution, Petitioner
`filed a Request for Rehearing, which was denied. Papers 10, 11. Patent
`
`
`1 U.S. Patent No. 6,091,725 (issued July 18, 2000) (Ex. 1002).
`2 European Patent Application No. 0 522 743 A1 (published January 13,
`1993) (Ex. 1003).
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`Owner filed a Patent Owner Response. Paper 12 (“PO Resp.”). Petitioner
`filed a Reply to the Patent Owner Response. Paper 14 (“Pet. Reply”).
`On April 24, 2018, the Supreme Court held that a final written
`decision in an inter partes review must decide the patentability of all claims
`challenged in the petition. SAS Inst. Inc. v. Iancu, 138 S. Ct. 1348, 1359–60
`(2018) (“SAS”). Pursuant to SAS, on May 3, 2018, we instituted inter partes
`review on the following additional grounds:
`-whether claims 1, 2, and 21 would have been obvious under
`35 U.S.C. § 103(a) in view of Cheriton;
`-whether claims 3, 5, and 6 would have been obvious under
`35 U.S.C. § 103(a) in view of Cheriton and Kessler3;
`-whether claims 4 and 22–24 would have been obvious under
`35 U.S.C. § 103(a) in view of Cheriton, Kessler, and Jain; and
`-whether claims 12–14 would have been obvious under
`35 U.S.C. § 103(a) in view of Cheriton and Jain.
`See Paper 15; see also PGS Geophysical AS v. Iancu, 891 F.3d 1354, 1360–
`61 (Fed. Cir. 2018) (reading “the SAS opinion as interpreting the statute to
`require a simple yes-or-no institution choice respecting a petition, embracing
`all challenges included in the petition”); Guidance on the Impact of SAS on
`AIA Trial Proceedings (April 26, 2018) (available at
`https://www.uspto.gov/patents-application-process/patent-trial-and-
`
`3 R.E. Kessler, Inexpensive Implementations of Set-Associativity, ACM
`SIGARCH COMPUTER ARCHITECTURE NEWS–SPECIAL ISSUE:
`PROCEEDINGS OF THE 16TH ANNUAL INTERNATIONAL
`SYMPOSIUM ON COMPUTER ARCHITECTURE, 17:3, 131–139 (June
`1989) (Ex. 1004). Petitioner provides a stamped copy of the portion of the
`Proceedings (Ex. 1005), and a declaration attesting to the authenticity of the
`document and its public availability. Ex. 1006.
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`appealboard/trials/guidance-impact-sas-aia-trial) (“[I]f the PTAB institutes a
`trial, the PTAB will institute on all challenges raised in the petition.”). The
`parties were requested to advise the Board if they wished to change the case
`schedule or submit further briefing in light of the institution on additional
`claims and grounds. Paper 15, 1. Petitioner requested leave to file
`additional supplemental briefing on the newly-instituted grounds, and the
`request was granted. Paper 16, 2–3. Petitioner later raised a request to
`submit additional evidence and that request was denied. Paper 17, 2–7.
`Petitioner filed a Supplemental Reply (Paper 18, “Pet. Supp. Reply”).
`An oral hearing was held on August 2, 2018. A transcript of the
`hearing is included in the record. Paper 29 (“Tr.”).
`B. Related Proceedings
`Patent Owner indicates that related matters are these Eastern District
`
`of Texas cases: Plectrum LLC v. Arista Networks, Inc., Case No. 4:17-cv-
`00076; Plectrum LLC v. Brocade Communications Systems, Inc., Case No.
`4:17-cv-00077; Plectrum LLC v. Extreme Networks, Inc., Case No. 4:17-cv-
`00079; Plectrum LLC v. Facebook, Inc., Case No. 4:17-cv-00081; Plectrum
`LLC v. Fortinet, Inc., Case No. 4:17-cv-00082; Plectrum LLC v. Huawei
`Technologies USA, Inc., Case No. 4:17-cv-00083; Plectrum LLC v. Juniper
`Networks, Inc., Case No. 4:17-cv-00084; Plectrum LLC v. AT&T, Inc., Case
`No. 4:17-cv-00120; Plectrum LLC v. Broadcom Corporation, Case No.
`4:17-cv-00121; Plectrum LLC v. Comcast Corporation, Case No. 4:17-cv-
`00123; Plectrum LLC v. F5 Networks, Inc., Case No. 4:17-cv-00124;
`Plectrum LLC v. NEC Corporation of America, Case No. 4:17-cv-00125;
`Plectrum LLC v. Verizon Communications, Inc., Case No. 4:17-cv-00126;
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`Plectrum LLC v. Nokia USA, Inc., Case No. 4:17-cv-00140; and Plectrum
`LLC v. Oracle Corporation, Case No. 4:17-cv-00141. Paper 6, 2.
`C. The ’951 Patent
`The ’951 patent is entitled “High Speed Cache Management Unit for
`
`Use in a Bridge/Router,” and was filed as application No. 08/927,336 on
`September 11, 1997, and issued on November 2, 1999. Ex. 1001, [21], [22],
`[45], [54].
`
`The ’951 patent is directed to providing a network address cache.
`Ex. 1001, 1:23–31. The network address cache maintains hardware address
`and age tables, searches the address table for addresses received in network
`frames, and returns address search results, such as the destination port(s) for
`the received frame. Id. at 1:30–39. When a frame is received, the addresses
`in the frame are looked up, and the data associated with the cached addresses
`is returned in order to process the frame. Id. at 1:41–52.
`
`Figure 2, reproduced below, depicts a block diagram illustrating a
`network interface module coupled to a motherboard via a backplane.
`Ex. 1001, 2:56–59.
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`
`Figure 2, above, illustrates that the network interface module receives and
`sends data via input port 18 and output port 20, and when a frame is
`received, it is sent to receive header processor 46. Ex. 1001, 3:31–35, 3:61–
`64. Motherboard 12 includes address cache ASIC (“ACA”) 26, with
`associated cache 28, frame processor 30, application processor 31, and
`master buffer ASIC (“MBA”) 32. Id. at 3:57–60. Receive header
`processor 46 derives information from the header and passes that
`information to the ACA. Id. at 7:53–59. ACA 26 looks up addresses cached
`in associated cache 28. Id. at 4:20–21.
`
`In an embodiment of the ’951 patent, cache 28 is a 4-way associative
`cache, where each row of the cache is associated with one entry from each of
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`the four sets. Ex. 1001, 5:14–17. Figure 4A, reproduced below, depicts the
`arrangement of cache 28.
`
`
`Figure 4A, above, illustrates the organization of a portion of cache 28.
`Ex. 1001, 2:64–65, 5:14–17. A cache lookup is started by the receipt of an
`address to be searched by the ACA. Id. at 5:25–27. A cyclic redundancy
`code (“CRC”) process is performed by a CRC engine on the address to
`generate a code, and the code is then used to identify a cache row. Id. at
`5:27–31. The ACA uses an algorithm to identify a set order for address
`comparison, and a valid table is used for reference to identify if any of the
`sets are invalid. Id. at 5:30–34. A most likely valid set in the identified row
`is chosen, and the stored value is compared against the address from which
`the CRC is generated. Id. at 5: 34–37. If a match occurs, the associated data
`is returned, and if no match occurs, the next valid set in the row is selected
`and compared to the received address. Id. at 5:37–41. Upon a match, the
`frame is forwarded. Id. at 4:60–5:1.
`
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`
`Illustrative independent claims 1 and 8 are reproduced below.
`
`1. A method for selecting an output port eligible to be used for
`transmission of a frame received at a computer network device,
`wherein said computer network device has at least one input port
`and a plurality of output ports and said received frame has a source
`address and a received destination address, said method
`comprising the steps of:
`receiving said frame at one of said at least one input port of said
`computer network device;
`parsing said received destination address from said received
`frame;
`processing said received destination address with a code
`generator to generate a coded address;
`comparing said coded address to a value associated with a row
`within said cache;
`in the event of a match between said coded address and said
`value associated with said row, comparing said received
`destination address with a cached destination address associated
`with a first entry in said row;
`in the event of a match between said received destination
`address and said cached destination address associated with
`said first entry, reading a port mask associated with said first
`entry to identify at least one port from said plurality of output
`ports which is eligible for transmission of said received frame.
`8. A cache management unit of a data unit forwarding network
`device, comprising:
`an input register for receiving data unit header information
`including received source and destination address;
`a cyclic redundancy code (CRC) generator in communication
`with said input register for executing a CRC algorithm on each
`of said received source and destination addresses from said
`input register to form respective CRC encoded addresses;
`an input packetizer in communication with said CRC generator
`and said input register for formatting said CRC encoded
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`addresses and for receiving said received source and destination
`addresses from said input register;
`a cache lookup unit and an associated cache in communication
`with said input packetizer for searching said cache with said
`formatted CRC encoded addresses;
`an output packetizer in communication with said cache lookup
`unit for receiving and formatting retrieved source and
`destination address information from said cache; and
`output register in communication with said output packetizer
`for receiving said formatted retrieved source and destination
`address information.
`Ex. 1001, 16:22–45, 17:22–46.
`
`II. ANALYSIS
`A. Real Parties-in-Interest
` The statute governing inter partes review proceedings sets forth
`
`certain requirements for a petition for inter partes review, including that “the
`petition identif[y] all real parties in interest.” 35 U.S.C. § 312(a); see also
`37 C.F.R. § 42.8(b)(1) (requirement to identify real parties-in-interest in
`mandatory notices). In accordance with 35 U.S.C. § 312(a)(2) and 37 C.F.R.
`§ 42.8(b)(1), Petitioner identifies Unified Patents Inc. as the sole real
`party-in-interest and “certifies that no other party exercised control or could
`exercise control over Unified’s participation in this proceeding, the filing of
`this petition, or the conduct of any ensuing trial.” Pet. 1. Petitioner provides
`verified Voluntary Interrogatory Responses (Ex. 1020) in support of the
`assertion that Unified is the sole real party-in-interest.
`
`In its Response, Patent Owner argues the Petition should be denied
`because Petitioner fails to provide sufficient evidence to show that it has
`named all real parties-in-interest. See PO Resp. 8–15. More specifically,
`Patent Owner alleges that when sufficient evidence to the contrary is
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`provided by a patent owner, the ultimate burden of proof remains with
`petitioner to establish that it has identified all real parties in interest. Id. at
`8–9 (citing Jiawei Tech. Ltd. v. Simon Nicholas Richmond, IPR2014-00935,
`slip op. at 5 (PTAB August 21, 2015) (Paper 52); Corning Optical Comms.
`RF, LLC v. PPC Broadband, Inc., IPR2014-00440, slip op. at 5–6 (PTAB
`August 18, 2015) (Paper 68); Office Patent Trial Practice Guide, 77 Fed.
`Reg. 48,759–60 (Aug. 14, 2012)).4 Patent Owner contends that Petitioner’s
`primary source of revenue is from subscription fees or other payments made
`by its member companies, and these fees are paid are “expressly for the
`purpose of funding [Petitioner’s] defensive patent activities, such as filing
`IPR petitions.” Id. at 10 (citing Ex. 2003, 3–5, 8; Ex. 2005; Ex. 1020, 2).
`Patent Owner argues that Petitioner has no other source of revenue, and the
`members’ annual subscription fees “are in fact funding this IPR,” and these
`facts give rise to a strong inference that the Petitioner’s members have
`“implicitly authorized” the filing of this IPR. Id. at 12–13.
`
`Patent Owner alleges that Petitioner’s purpose and business model is
`to undertake activities to serve the beneficial interests of its members in
`defending against patents. PO Resp. 10. Patent Owner references an early
`press release by Petitioner that indicates that Petitioner “aims to level the
`playing field” for companies that include Google, NetApp, and others. Id.
`(citing Ex. 2002). Patent Owner refers to Petitioner’s alleged “collaborative
`deterrent strategy” that is implemented in connection with its members. Id.
`Patent Owner refers to Petitioner’s strategy that uses “Micro-Pools” of
`
`
`4 Evidentiary issues related to real parties-in-interest are discussed below in
`view of the more recent Federal Circuit case, Worlds Inc. v. Bungie, Inc.,
`903 F. 3d 1237 (Fed. Cir. 2018).
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`member groups, in order to align deterrent solutions with its participating
`companies. Id. at 10–11. Patent Owner further alleges that Petitioner “has
`made clear that filing IPR Petitions is an important aspect of its collaborative
`defense strategy that it executes in coordination with and on behalf of its
`members.” Id. at 11. Patent Owner argues that Petitioner has no strategic
`technologies to sell, short of its defense services to its member technology
`members. Id. Patent Owner alleges that the member companies “would not
`agree to pay large annual subscription fees to [Petitioner] unless those
`companies saw [Petitioner’s] filing of IPR petitions as serving the
`technology companies’ interests.” Id. at 12.
`
`Patent Owner also contends that Petitioner’s interrogatory responses
`(Ex. 1020) fail to establish that all real parties-in-interest have been named
`in the Petition because: (1) the interrogatories fail to address
`communications relating to the selection of the patent to challenge; (2) the
`statement that this IPR is not funded by members is limited to direct
`funding, but there must be indirect funding; and (3) the issue of whose
`beneficial interest being served is not addressed.5 PO Resp. at 13–14.
`
`Petitioner bears the burden of persuasion in establishing that all real
`parties in interest have been named. See Worlds Inc., 903 F. 3d at 1241–
`1242. Petitioner’s identification of the real parties-in-interest is generally
`
`
`5 The interrogatory responses were signed by Mr. Kevin Jakel, the CEO of
`Petitioner, Unified Patents Inc. See Ex. 1020. In its Response, Patent
`Owner indicated an intent to depose Mr. Jakel as part of its routine
`discovery, but there is no notice of that deposition in the record, and Patent
`Owner does not refer to any deposition testimony. See PO Resp. 13 n.2.
`Patent Owner also “reserve[d] its right to seek additional discovery on the
`real party-in-interest issue”; however, no related request for this discovery
`was made. See id.
`
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`accepted at the time of filing the petition, unless the patent owner produces
`“some evidence that tends to show that a particular third party should be
`named as a real party in interest . . . . A mere assertion that a third party is an
`unnamed real party in interest, without any support for that assertion, is
`insufficient to put the issue into dispute.” Id. at 1244.
`
`“Determining whether a non-party is a ‘real party in interest’ demands
`a flexible approach that takes into account both equitable and practical
`considerations, with an eye toward determining whether the non-party is a
`clear beneficiary that has a preexisting, established relationship with the
`petitioner.” Applications in Internet Time, LLC v. RPX Corp., 897 F.3d
`1336, 1351 (Fed. Cir. 2018) (“AIT”). Whether a particular entity is a real
`party-in-interest is a “highly fact-dependent question” that is assessed “on a
`case-by-case basis.” Office Patent Trial Practice Guide, 77 Fed. Reg.
`48,756, 48,759 (Aug. 14, 2012) (citing Taylor v. Sturgell, 553 U.S. 880,
`893–95 (2008)). While multiple factors may be relevant to the inquiry, “[a]
`common consideration is whether the non-party exercised or could have
`exercised control over a party’s participation in a proceeding.” Id.; see also
`Zoll Lifecor Corp. v. Philips Elec. North Am. Corp., Case IPR2013–00609,
`slip op. at 10 (PTAB Mar. 20, 2014) (Paper 15). Relevant factors in the real
`parties-in-interest analysis include “Party A’s relationship with the
`petitioner; Party A’s relationship to the petition itself, including the nature
`and/or degree of involvement in the filing; and the nature of the entity filing
`the petition.” Trial Practice Guide, 48,760.
`
`Patent Owner generally contends that Petitioner’s members are the
`intended beneficiaries of this inter partes review and their subscription fees
`have funded it. PO Resp. 8–12. Patent Owner provides no evidence, for
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`example, identifying any member entity that it alleges is controlling this
`particular proceeding, or a member that has financed, in whole or in part,
`this proceeding. See id.; see also Ex. 1020, 2–5. In AIT, the analysis of real
`parties-in-interest requires more than determining whether a party generally
`benefits from an inter partes review; AIT considered the ties between the
`filing entity and another party and the nature and degree of relationship
`between them and how that is relevant to the particular inter partes review.
`See AIT, 897 F.3d at 1339–1342, 1355–1358. The fact that members
`provide payment to Petitioner for a subscription to Petitioner’s services
`alone is insufficient to show that specific members are funding, directly or
`indirectly, this inter partes review. Based on the full record, the evidence is
`insufficient to support that Petitioner has requested this inter partes review
`proceeding on behalf of any particular member (see Ex. 1020 at 5), or to
`support that any of Petitioner’s members have had control over when and
`how Petitioner spent the revenue received from its members related to this
`proceeding (see id. at 2–3, 5). In sum, there is insufficient evidence that any
`specific member derives benefit from this proceeding.
`Although the evidence demonstrates that Petitioner made decisions
`regarding this inter partes review proceeding, including which patent and
`claims to challenge, as discussed, there is insufficient evidence in the record
`that any particular member provided input regarding this proceeding, nor is
`there support that is contrary to Petitioner’s bearing the cost of this
`proceeding. See Ex. 1020 at 2–5. We acknowledge that the evidence shows
`Petitioner’s business is to “deter NPE litigation by protecting technology
`sectors.” Id. at 2; see also Ex. 2002; Ex. 2003, 3−5. And Petitioner does
`this by, at least in part, filing IPRs. Id. Thus, like in ATI, there is evidence
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`that Petitioner is not a traditional trade association, but a company seeking to
`protect its clients from patent risk in return for payment. See Ex. 1020 at 5
`(stating that members pay a yearly subscription in return for Petitioner
`performing “NPE-deterrent activities”); Ex. 2002 (“Because companies only
`participate in (and pay for) those Micro-Pools they choose, Unified Patents
`tightly aligns its deterrent solution with is participating companies.”).
`However, unlike in ATI, we have no evidence tying Petitioner’s NPE-
`deterrent activities to any particular member interested in the outcome of
`this proceeding, such as a member that has been accused previously of
`patent infringement. From the evidence presented, we have insufficient
`information regarding whether Petitioner evaluated any of its member’s
`interests when determining whether to file IPR petitions, such that we could
`assess the likelihood of unnamed real parties-in-interest. Instead, we have
`here Patent Owner’s mere assertions that unnamed real parties-in-interest
`might exist. Accordingly, we find that Patent Owner has not produced
`evidence tending to show that any particular party should be named as a real
`party-in-interest. Based on our review of the evidence before us, including
`Petitioner’s verified interrogatory responses, Petitioner has demonstrated, by
`the preponderance of the evidence, that it is the sole real party-in-interest.
`
`Thus, on the complete record before us, we find the evidence
`insufficient to support denial of the Petition for failure to name all real
`parties-in-interest.
`
`B. Level of Ordinary Skill in the Art
`
`Dr. Seshan testifies that a person of ordinary skill in the art for the
`
`’951 patent would have been an electrical engineer or computer engineer
`having a bachelor’s degree and two years of experience in designing
`
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`network switching/routing hardware, or equivalent postgraduate education,
`such as a master’s degree focused in networking systems. Ex. 1007 ¶ 45;
`see also Pet. 16. Patent Owner does not provide alternative proposed
`qualifications for a person of skill in the art. See PO Resp. 1–16.
`
`We adopt and apply the assessment of the level of ordinary skill in the
`
`art articulated by Petitioner to our obviousness analysis in this proceeding.
`In addition, we note that the art of record in this proceeding—namely,
`Cheriton, Kessler, and Jain—is indicative of the level of ordinary skill in the
`art. See Okajima v. Bourdeau, 261 F.3d 1350, 1355 (Fed. Cir. 2001).
`
`C. Claim Construction
`Petitioner asserts that because the ’951 patent expired on September
`11, 2017, a district court-type claim construction under Phillips v. AWH
`Corp. should be applied pursuant to 37 C.F.R. § 42.100. Pet. 18. With this,
`Petitioner asserts that the ordinary and customary meaning of the claim
`terms, as understood by one of ordinary skill at the time of the invention,
`should be applied. Id. Petitioner presents proposed constructions for the
`terms “code generator,” “coded address,” and “encoding.” Id. at 19–20.
`Patent Owner does not dispute the’951 patent expiry date represented in the
`Petition, and does not present its own proposed constructions or dispute
`Petitioner’s proposed constructions of claim terms. PO Resp. 1–16.
`We determine that it is not necessary to provide an express
`construction of any claim term for our analysis in this Final Written
`Decision. Vivid Techs., Inc. v. Am. Sci. & Eng’g, Inc., 200 F.3d 795, 803
`(Fed. Cir. 1999) (“[O]nly those terms need be construed that are in
`controversy, and only to the extent necessary to resolve the controversy.”).
`
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`D. Obviousness of Claims 1, 2, and 21 over Cheriton, Claims 3, 5, and 6
`over Cheriton and Kessler, and Claims 4 and 22–24 over
`Cheriton, Kessler, and Jain
` Petitioner contends that independent claims 1, 2, and 21 are obvious
`over Cheriton, claims 3, 5, and 6 are obvious over Cheriton and Kessler, and
`claims 4 and 22–24 are obvious over Cheriton, Kessler, and Jain. Pet. 21–
`51; Pet. Supp. Reply 2–9. To support its contentions, Petitioner provides
`evidence and explanations as to how the prior art allegedly teaches each
`claim limitation. Id. Petitioner also relies upon the Seshan Declaration to
`support its positions. Ex. 1007. Patent Owner counters that the prior art
`does not render these claims obvious because the Petition provides only
`conclusory statements that lack support, and the prior art fails to teach some
`of the claim limitations. Prelim. Resp. 5–10.
` On the complete record, we determine that Petitioner’s explanations
`and evidence are insufficient to support the obviousness grounds asserted
`under Cheriton for independent claims 1, 2, and 21, and also are insufficient
`for the obviousness grounds for dependent claims 3–6 and 22–24 under
`Cheriton in combination with other prior art. We begin our discussion with
`a brief summary of Cheriton, Kessler, and Jain, and then address the
`evidence, analysis, and arguments presented by the parties.
`1. Cheriton (Ex. 1002)
`Cheriton is directed to a network device that switches network traffic
`
`based upon network addresses. Ex. 1002, 1:20–22, 4:58–61. Cheriton
`discloses caching network addresses, with supporting hardware. Id. at 5:32–
`38. Figure 4, reproduced below, depicts a block diagram of Cheriton’s
`network switching device. Id. at 5:60–61.
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`As depicted in Figure 4, input ports 401–404 receive data, and switch
`hardware is used to decode the source and destination addresses and
`generates virtual path index 630. Ex. 1002, 5:32–34, 8:32–34, 10:41–45.
`Virtual path index 630 enters hash function 631 (shown in Figure 6), and a
`lookup for virtual path cache 415 is performed. Id. at 9:34–38, 10:42–45.
`Cheriton compares the received address against the stored tag fields, and the
`matching record is output. Id. at 9:38–43. The stored entry is used to
`identify a respective output port (404–408), on which the packet is to be
`transmitted, and switch hardware 409 forwards the data packet accordingly.
`Id. at 7:51–53, 10:57–59, Fig. 3.
`2. Kessler (Ex. 1004)
`Kessler is directed to implementations of set-associativity in cache
`
`memories. Ex. 1004, 131. Kessler discusses addressing the order of entries
`in a cache, and refers to a “MRU [most-recently-used] Approach” where
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`tags are examined in order from the most recently used to least recently
`used. Id. at 132. Entries that have been most recently accessed are stored in
`a list of entries referred to as an “MRU list per set.” Id.
`3. Jain (Ex. 1003)
`Jain is directed to data communications and recognizing local area
`
`network addresses. Ex. 1003, 2:3–4. A destination address list is used
`which contains a set of addresses that are compared to the destination
`address of received frames. Id. at 3:3–5, 5:58–61. A “hashing function
`generator is supplied to operate upon the received bit stream.” Id. at 5:58–
`6:1. In a preferred embodiment, “the hashing function generator is a Cyclic
`Redundancy Check [CRC] generator, although the teaching of the invention
`is not limited to only the use of a CRC technique.” Id. at 6:1–2. Jain
`discloses that the hash function generator may employ XOR methods,
`among other techniques. Id. at 6:2–4.
`4. Analysis
`Petitioner bears the burden of proving unpatentability of the
`challenged claims, and the burden of persuasion never shifts to Patent
`Owner. Dynamic Drinkware, LLC v. Nat’l Graphics, Inc., 800 F.3d 1375,
`1378 (Fed. Cir. 2015). To prevail on its challenges, Petitioner must
`demonstrate by a preponderance of the evidence that the challenged claims
`are unpatentable. 35 U.S.C. § 316(e); 37 C.F.R. § 42.1(d).
` A patent claim is unpatentable under 35 U.S.C. § 103(a) if the
`differences between the claimed subject matter and the prior art are such that
`the subject matter, as a whole, would have been obvious at the time the
`invention was made to a person having ordinary skill in the art to which said
`subject matter pertains. KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 406
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`(2007). The question of obviousness is resolved on the basis of underlying
`factual determinations including: (1) the scope and content of the prior art;
`(2) any differences between the claimed subject matter and the prior art;
`(3) the level of ordinary skill in the art; and (4) objective evidence of
`nonobviousness.6 Graham v. John Deere Co., 383 U.S. 1, 17–18 (1966).
`Claim 1
`Petitioner alleges that Cheriton teaches or suggests all the limitations
`
`of independent claim 1 in the view of one of ordinary skill in the art.
`Pet. 21–36. Petitioner contends that Cheriton teaches a method that selects
`an output port for transmission of a received frame. Id. at 24 (citing Ex.
`1002, 7:17–21, 7:50–52, 9:4–20, Fig. 3; Ex. 1007 ¶ 67). Petitioner argues
`that Cheriton teaches a computer network device with input and output
`ports, which receives a frame at an input port, and parses a received
`destination address from a received frame. Id. at 25–27 (citing, inter alia,
`Ex. 1002, 6:8–11, 6:49–51, 8:24–26, 8:32–34, 9:34–36, 10:42–44, Figs. 2, 4;
`Ex. 1007 ¶¶ 70, 73, 75, 78, 79). Petitioner asserts that Cheriton teaches the
`claim 1 limitation “processing said received destination address with a code
`generator to generate a coded address” by its teaching of a hash
`function 632 that takes the destination and source addresses as input, and
`produces a hash output that is the virtual path cache index 632, as shown in
`Figure 7. Id. at 28–30 (citing Ex. 1002, 9:6–8, 9:34–38, 9:48–56, Fig. 7; Ex.
`1007 ¶¶ 82–85). Petitioner argues that, even though Cheriton’s hash
`function uses both source and destination as inputs, Cheriton still meets the
`
`
`6 Patent Owner does not present arguments or evidence of objective indicia
`of nonobviousness.
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`claim 1 limitation of processing a destination address because the limitation
`does not require processing using only a destination address. Id. at 29.
` Petitioner alleges that Cheriton teaches the claim 1 limitation of
`“comparing said coded address to a value associated with a row within a
`cache” because Cheriton discloses that virtual path cache index 632 “is used
`to ‘look[] up the four parallel sets of the virtual path cache SRAMs 601
`through 604.’” Pet. 30 (citing Ex. 1002, 9:34–38). Petitioner refers to
`Cheriton’s description of the virtual path cache index 632 for “index[ing] the
`four set associative virtual path cache 601 through 604,” and the virtual path
`index 632 is “further compared.” Id. (citing Ex. 1002, 10:46–50). Petitioner
`argues that “[t]o the extent Cheriton does not explicitly state that the lookup
`or indexing was done by comparing the virtual path cache index to a value
`associated with a row in the cache, it would have been obvious to a person
`of ordinary skill in the art to compare the virtual path cache index in such a
`fashion.” Id. Petitioner further alleges that “Cheriton would have compared
`the virtual path cache index to either the row number or cache offset
`associated with a row of data” because “[t]his comparison would have been
`necessary to retrieve the data from the row.” Id. at 30–31 (citing Ex. 1007
`¶ 88). Dr. Seshan repeats the same assertion, and testifies that “[s]uch an
`approach would have been nothing more than using a known technique
`(comparing an index value to an identifier value to determine if the identifier
`r