Case: 19-2191   Document: 47     Page: 1   Filed: 05/14/2020




        NOTE: This disposition is nonprecedential.


   United States Court of Appeals
       for the Federal Circuit
                 ______________________

           BUSHNELL HAWTHORNE, LLC,
                Plaintiff-Appellant

                            v.

                CISCO SYSTEMS, INC.,
                   Defendant-Appellee
                 ______________________

                       2019-2191
                 ______________________

    Appeal from the United States District Court for the
 Eastern District of Virginia in No. 1:18-cv-00760-TSE-
 MSN, Judge T. S. Ellis, III.
                 ______________________

                 Decided: May 14, 2020
                 ______________________

    BRIAN SHERWOOD SEAL, Butzel Long, PC, Washington,
 DC, for plaintiff-appellant. Also represented by MITCHELL
 ZAJAC, Detroit, MI.

     ELIZABETH BRANNEN, Stris & Maher LLP, Los Angeles,
 CA, for defendant-appellee. Also represented by DOUGLAS
 D. GEYSER, JOHN STOKES, PETER K. STRIS.
                 ______________________
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 2           BUSHNELL HAWTHORNE, LLC    v. CISCO SYSTEMS, INC.



     Before O’MALLEY, BRYSON, and CHEN, Circuit Judges.
 O’MALLEY, Circuit Judge.
      Bushnell Hawthorne, LLC (“Bushnell”) appeals a deci-
 sion of the United States District Court for the Eastern Dis-
 trict of Virginia holding all asserted claims of U.S. Patent
 No. 7,933,951 (“’951 patent”) invalid as indefinite pursuant
 to 35 U.S.C. § 112(b). Bushnell Hawthorne, LLC v. Cisco
 Sys., Inc., No. 1:18-CV-760, 2019 WL 2745735 (E.D. Va.
 July 1, 2019). For the reasons discussed below, we affirm.
                       I. BACKGROUND
                     A. The ’951 Patent
      The ’951 patent, titled “Systems and Methods for Dis-
 cerning and Controlling Communication Traffic,” relates
 “to identifying various types of communication traffic and
 controlling movement of that traffic within a communica-
 tions network.” ’951 patent, col. 1, ll. 1–3, 18–20. The in-
 vention “permit[s] redirection of only certain types of
 communication traffic of interest[,] for example HTTP traf-
 fic, while permitting other types of communication, for ex-
 ample SMTP traffic, to pass without redirection.” Id. at
 Abstract. This invention is useful for redirecting internet
 traffic to generate advertising revenue. Id.
      Claim 1, the only independent claim in the ’951 patent,
 is representative of the claims at issue on appeal:
      1. A computer system for redirecting Internet com-
      munications, said system comprising:
         a first processor that receives information
         from a computer at a point of origin;
         a second processor that analyzes the infor-
         mation for one or more pre-defined bit
         strings or character sets;
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        a third processor that receives return infor-
        mation from a computer that communi-
        cates with other computers on the Internet;
        a fourth processor that analyzes the return
        information for said one or more pre-de-
        fined bit strings or character sets;
        a fifth processor that
            a) supplies one or more IP Ad-
            dresses for the information re-
            quested if one or more of the pre-
            defined bit strings or character sets
            are not encountered,
            b) supplies one or more second IP
            Addresses for the information re-
            quested if one or more different bit
            strings or character sets are en-
            countered,
            c) supplies one or more third IP Ad-
            dresses if one or more of the pre-de-
            fined bit strings or character sets
            are encountered and a higher level
            protocol can be inferred, and/or
            d) allows the traffic to flow thru un-
            modified; and
        a sixth processor that analyzes a request
        submitted to said different IP Address for
        one or more alternative bit strings or char-
        acter sets,
        wherein the alternative bit strings or char-
        acter sets are indicative of a particular
        higher level Internet communication proto-
        col, and
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 4           BUSHNELL HAWTHORNE, LLC     v. CISCO SYSTEMS, INC.



         wherein the system further comprises main-
         taining a list of bit strings or character sets
         for which a different IP Address should not
         be supplied, wherein the list is updated one
         or more times after creation of the list, and
         wherein the list is updated based on moni-
         toring of requests for: originating IP Ad-
         dress, requested hostname, size of a DNS
         query, frequency of a single hostname or
         domain name, port number, date, and/or
         time.
 ’951 patent, col. 21, ll. 9–45 (emphases added). Dependent
 claims 8, 13, and 15 contain additional limitations relevant
 to this appeal. Claim 8 requires “a seventh processor that
 receives a request to connect to a computer at said IP Ad-
 dress.” Id. at col. 22, ll. 7–8 (emphasis added). Claim 13
 provides “a tenth processor at the different IP Address.” Id.
 at col. 22, l. 24 (emphasis added). And claim 15 adds “items
 for the list are generated by the sixth processor that ana-
 lyzes a request submitted to said different IP Address.” Id.
 at col. 22, ll. 28–30 (emphasis added).
     With respect to the claim term “said different IP Ad-
 dress,” the specification provides:
     [T]he present invention provides a computer sys-
     tem for redirecting Internet communications,
     where the system comprises . . . a processor that
     analyzes a request submitted to the different IP Ad-
     dress for one or more alternative bit strings or char-
     acter sets, wherein the alternative bit strings or
     character sets are indicative of a particular higher
     level Internet communication protocol.
 Id. at col 13, ll. 3–25 (emphasis added). It also states:
     [T]he system may comprise maintaining a list of bit
     strings or character sets for which a different IP
     Address should not be supplied, for example
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     wherein items for the list are generated by the pro-
     cessor that analyzes a request submitted to said
     different IP Address. The list can be maintained by
     a processor that transparently passes DNS re-
     sponses if one or more conditions or pre-defined bit
     strings or character sets are not encountered, and
     that supplies a different IP Address if one or more
     of the conditions or pre-defined bit strings or char-
     acter sets are encountered. . . . In embodiments, a
     list is maintained on a computer that analyzes one
     or more requests submitted to the different IP Ad-
     dress and a list is maintained on a computer that
     analyzes the request(s) submitted to the different
     IP Address, where the two lists are compared to
     identify entries in common or not in common.
 Id. at col. 13, l. 47–col. 14, l. 1 (emphases added). Finally,
 the specification explains that:
     [I]n embodiments, the system can comprise means
     for . . . returning to the submitter of the request an
     IP Address that is different from that requested. In
     embodiments, the system further comprises means
     for receiving a request for the different IP Address;
     means for analyzing the request for the different IP
     Address for pre-defined bit strings or character sets
     indicative of a particular Internet protocol . . . .
 Id. at col. 17, ll. 42–57 (emphases added).
                B. District Court Proceedings
      Bushnell filed suit against Cisco Systems, Inc. (“Cisco”)
 in June 2018, alleging infringement of nineteen claims of
 the ’951 patent. The case proceeded to claim construction.
 In its claim construction briefing, Cisco argued that all
 claims of the ’951 patent were invalid as indefinite. Specif-
 ically, Cisco argued that “said different IP Address,” and
 related terms, are indefinite. Cisco further alleged that the
 claims are indefinite because they mix statutory classes of
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 6           BUSHNELL HAWTHORNE, LLC     v. CISCO SYSTEMS, INC.



 claims. Bushnell argued that all of the disputed terms
 carry their plain meaning. It contended that the plain
 meaning of the “different IP Address” terms is “an IP ad-
 dress supplied by the fifth processor that is different from
 the IP address for the information requested by the user or
 computer at the point of origin.” Bushnell Hawthorne,
 LLC, 2019 WL 2745735, at *2.
     Following a Markman hearing, the district court ruled
 in favor of Cisco, finding independent claim 1 indefinite on
 three separate grounds: (1) “said different IP Address”
 lacks antecedent basis and does not have a reasonably cer-
 tain meaning to a person of ordinary skill in the art
 (“POSA”); (2) “a different IP Address” does not have a rea-
 sonably certain meaning to a POSA; and (3) the final limi-
 tation, providing that “the system further comprises
 maintaining a list,” improperly mixes classes of statutory
 subject matter such that it is not clear if the claim is in-
 fringed by building or using the system. Id. at *2–9.
      First, the district court explained that the antecedent
 basis for “said different IP Address” is unclear—possibly
 referring to any of three types of IP addresses that claim 1’s
 fifth processor might supply: “one or more IP Addresses,”
 “one or more second IP Addresses,” or “one or more third
 IP Addresses.” Id. at *3. Because the IP addresses men-
 tioned in the fifth processor limitation are the first in-
 stances of the term “IP Addresses” in the claim, the district
 court presumed one of those was likely “said different IP
 Address.” Id. The fact that the fifth processor limitation
 claims three separate classes of IP addresses, however, led
 the district court to conclude that it was not possible to dis-
 cern which of the three addresses was referenced by the
 disputed limitation. Id. The district court further ex-
 plained that the confusion caused by the claim language is
 enhanced by the singular/plural mismatch between the
 fifth processor limitation’s potential to produce multiple IP
 addresses and the claimed singular “said different IP Ad-
 dress.” Id. at *4.
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     Beyond the claim language, the district court found
 that the specification provides no clarification on the mean-
 ing of the term because most of the specification suffers
 from the same lack of antecedent basis problem. Id. And,
 although the specification describes a “means for returning
 to the submitter of the request an IP Address that is differ-
 ent from that requested,” the remainder of the specification
 is ambiguous and makes what appear to be inconsistent
 uses of the term. Id. (quoting ’951 patent, col. 17, ll. 51–
 53). In some instances, the district court noted, the speci-
 fication refers to a requested IP address as “the different IP
 Address.” Id. (citing, inter alia, ’951 patent, col. 13, l. 22).
 Based on this intrinsic record, the district court found that
 a POSA would be unable to discern, with reasonable cer-
 tainty, whether a particular IP address was “said different
 IP Address” within the meaning of the claim. Id. at *5. It
 therefore held the claim indefinite. Id.
     Second, the district court found the claim term “a dif-
 ferent IP Address” indefinite. It explained,
     [l]ike the term “said different IP address,” the
     claim term “a different IP address” appears to al-
     lude to another IP address from which “a different
     IP address” is different. But the claim language
     and specification neither explain how or from what
     other IP address “a different IP address” differs nor
     otherwise clarify what constitutes “a different IP
     address.”
 Id. at *6.
     Third, the district court held claim 1 indefinite for im-
 properly combining the structural elements of a “computer
 system” with a method element, “maintaining a list.” Id.
 at *7–9. The district court further held dependent claims
 8, 13, and 15 indefinite based on the lack of clarity as to the
 meaning of the “IP Address” terms. Id. at *2–5, 6–7.
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 8           BUSHNELL HAWTHORNE, LLC      v. CISCO SYSTEMS, INC.



     Having found all asserted claims indefinite, the district
 court entered judgment for Cisco. J.A. 21. Bushnell ap-
 peals. We have jurisdiction pursuant to 28 U.S.C. § 1295.
                                II
      “[A] patent is invalid for indefiniteness if its claims,
 read in light of the specification delineating the patent, and
 the prosecution history, fail to inform, with reasonable cer-
 tainty, those skilled in the art about the scope of the inven-
 tion.” Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S.
 898, 901 (2014). We review a district court’s determination
 that a claim is indefinite de novo and subsidiary factual
 findings, if any, for clear error. Sonix Tech. Co. v. Publ’ns
 Int’l, Ltd., 844 F.3d 1370, 1376 (Fed. Cir. 2017).
     Bushnell argues that the district court erred in holding
 that “said different IP address,” and related terms, are in-
 definite. Appellant’s Br. 12–18. It contends that “said dif-
 ferent IP Address” clearly refers to an IP address to which
 the user has been redirected. Id. at 12. Its argument is
 unavailing.
      Claim 1 of the ’951 patent is, on its face, entirely un-
 clear as to the meaning of “said different IP Address.” As
 an initial matter, “said different IP Address” appears in the
 claim without antecedent basis. Prior to that point, the
 claim recites certain IP addresses, but never a “different”
 one. See ’951 patent, claim 1. The lack of antecedent basis
 signals a potential indefiniteness problem but does not end
 the inquiry. See Energizer Holdings, Inc. v. Int’l Trade
 Comm’n, 435 F.3d 1366, 1370 (Fed. Cir. 2006) (“Whether
 [a] claim, despite lack of explicit antecedent basis . . . none-
 theless has a reasonably ascertainable meaning must be
 decided in context.”).
     Moving to the broader context of the claim, however,
 only compounds the problem. Claim 1 describes three clas-
 ses of IP addresses prior to the “said different IP Address”
 limitation: “one or more IP Addresses,” “one or more second
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 IP Addresses,” or “one or more third IP Addresses.” ’951
 patent, claim 1. Each of those terms is presumed to have a
 separate meaning and, therefore, presumed to refer to dif-
 ferent classes of IP addresses. See Bd. of Regents v. BENQ
 Am. Corp., 533 F.3d 1362, 1371 (Fed. Cir. 2008). With
 three different IP addresses to choose from, a POSA faced
 with the “said different IP Address” limitation is left to
 wonder which of the different IP addresses is “said” differ-
 ent one.
     Further, the mismatch between the various plural IP
 addresses provided earlier in the claim and the singular
 “said different IP Address” suggests a term that is entirely
 untethered from the words around it. It is true that, as a
 general rule, a singular noun encompasses the plural for
 claim construction purposes. 01 Communique Lab., Inc. v.
 LogMeIn, Inc., 687 F.3d 1292, 1297 (Fed. Cir. 2012). This
 claim construction principle, however, does not render the
 mismatch irrelevant. Where, as here, a singular/plural
 mismatch further confuses an already confused claim, it is
 proper to consider the mismatch in discerning whether a
 POSA could understand the claim with reasonable cer-
 tainty.
      The specification does not clarify the meaning of “said
 different IP Address.” Much of the specification uses “the
 different IP Address” or “said different IP Address” in the
 same way as the claim—without explanation or antecedent
 basis. At one point, the specification appears to indicate,
 contrary to Bushnell’s contention, that the “different” IP
 address the patent refers to is the one which was re-
 quested. See ’951 patent, col. 13, ll. 21–22 (“a processor
 that analyzes a request submitted to the different IP Ad-
 dress”). At another, the specification provides comparing
 one list of requests submitted to “the different IP Address”
 to another list of requests submitted to “the different IP
 Address”—reasonably indicating that those two uses of
 “different IP Address” are not, even in the same sentence,
 referring to identical data sets. Id. at col. 13, l. 63–col.14,
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 10          BUSHNELL HAWTHORNE, LLC      v. CISCO SYSTEMS, INC.



 l. 1. Given this backdrop, the single sentence in the speci-
 fication that potentially supports Bushnell’s interpretation
 is insufficient to save the claim. See id. at col. 17, ll. 51–53
 (“means for returning to the submitter of the request an IP
 Address that is different from that requested”).
     The meaning of “said different IP Address” is entirely
 unclear on the record before us. A POSA, faced with the
 claims and the specification, 1 could not, with reasonable
 certainty, discern the meaning of the claim term. See Nau-
 tilus, Inc., 572 U.S. at 901. We thus hold claim 1, and all
 claims depending therefrom, indefinite.
                               III
     Because we affirm the district court as to the “said dif-
 ferent IP Address” limitation and hold all asserted claims
 indefinite, we do not address the remaining issues raised
 on appeal. For the reasons discussed above, we affirm the
 district court’s decision.
                         AFFIRMED




      1  Neither party argues that the prosecution history
 sheds light on the meaning of “said different IP Address.”
 Accordingly, we do not consider it here.
