`
`IN THE UNITED STATES DISTRICT COURT
`FOR THE EASTERN DISTRICT OF TEXAS
`TYLER DIVISION
`
`CASE NO. 6:10-CV-417
`
`§ § § § § §
`
`§ § § § §
`
`VIRNETX INC.,
`
`Plaintiff,
`
`vs.
`
`CISCO SYSTEMS, INC., et al.,
`
`Defendants.
`
`MEMORANDUM OPINION AND ORDER
`
`This Memorandum Opinion construes the disputed claim terms in U.S. Patent Nos.
`
`6,502,135 (“the ‘135 Patent”), 6,839,759 (“the ‘759 Patent”), 7,188,180 (“the ‘180 Patent”),
`
`7,418,504 (“the ‘504 Patent”), 7,490,151 (“the ‘151 Patent”), and 7,921,211 (“the ‘211 Patent”).
`
`Further, as stated at the Markman hearing and agreed by the parties, the Court ORDERS
`
`that VirnetX Inc.’s Motion to Compel from Apple a Complete Response to VirnetX’s Eighth
`
`Common Interrogatory (Docket No. 179) is DENIED AS MOOT.
`
`BACKGROUND
`
`VirnetX Inc. (“VirnetX”) asserts all six patents-in-suit against Aastra Technologies Ltd.;
`
`Aastra USA, Inc.; Apple Inc.; Cisco Systems, Inc.; NEC Corporation; and NEC Corporation of
`
`America (collectively “Defendants”). The ‘135 Patent discloses a method of transparently
`
`creating a virtual private network (“VPN”) between a client computer and a target computer. The
`
`‘759 Patent discloses a method for establishing a VPN without a user entering user identification
`
`information. The ‘180 Patent discloses a method of establishing a secure communication link
`
`between two computers. The ‘504 and ‘211 Patents disclose a secure domain name service. The
`
`1
`
`Petitioner RPX Corporation - Ex. 1049, p. 1
`
`MICROSOFT 1015
`
`Petitioner Apple Inc. - Exhibit 1015, p.1
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 2 of 31 PageID #: 7522
`
`‘151 Patent discloses a domain name service capable of handling both standard and non-standard
`
`domain name service queries.
`
`The patents-in-suit are all related; Application No. 09/504,783 (“the ‘783 Application”) is
`
`an ancestor application for every patent-in-suit. The ‘135 Patent issued on December 31, 2002,
`
`from the ‘783 Application. The ‘151 Patent issued from a division of the ‘783 Application. The
`
`‘180 Patent issued from a division of a continuation-in-part of the ‘783 Application. Both the
`
`‘759 and ‘504 Patents issued from a continuation of a continuation-in-part of the ‘783
`
`Application. Finally, the ‘211 Patent is a continuation of the application that resulted in the ‘504
`
`patent.
`
`The Court has already construed many of the terms at issue in a previous case that
`
`involved the ‘135, ‘759, and ‘180 Patents. See VirnetX, Inc. v. Microsoft Corp., 2009 U.S. Dist.
`
`LEXIS 65667, No. 6:07cv80 (E.D. Tex. July 30, 2009) (“Microsoft”).
`
`APPLICABLE LAW
`
`“It is a ‘bedrock principle’ of patent law that ‘the claims of a patent define the invention
`
`to which the patentee is entitled the right to exclude.’” Phillips v. AWH Corp., 415 F.3d 1303,
`
`1312 (Fed. Cir. 2005) (en banc) (quoting Innova/Pure Water Inc. v. Safari Water Filtration Sys.,
`
`Inc., 381 F.3d 1111, 1115 (Fed. Cir. 2004)). In claim construction, courts examine the patent’s
`
`intrinsic evidence to define the patented invention’s scope. See id.; C.R. Bard, Inc. v. U.S.
`
`Surgical Corp., 388 F.3d 858, 861 (Fed. Cir. 2004); Bell Atl. Network Servs., Inc. v. Covad
`
`Commc’ns Group, Inc., 262 F.3d 1258, 1267 (Fed. Cir. 2001). This intrinsic evidence includes
`
`the claims themselves, the specification, and the prosecution history. See Phillips, 415 F.3d at
`
`1314; C.R. Bard, Inc., 388 F.3d at 861. Courts give claim terms their ordinary and accustomed
`
`meaning as understood by one of ordinary skill in the art at the time of the invention in the
`
`2
`
`Petitioner RPX Corporation - Ex. 1049, p. 2
`
`Petitioner Apple Inc. - Exhibit 1015, p.2
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 3 of 31 PageID #: 7523
`
`context of the entire patent. Phillips, 415 F.3d at 1312–13; Alloc, Inc. v. Int’l Trade Comm’n,
`
`342 F.3d 1361, 1368 (Fed. Cir. 2003).
`
`The claims themselves provide substantial guidance in determining the meaning of
`
`particular claim terms. Phillips, 415 F.3d at 1314. First, a term’s context in the asserted claim
`
`can be very instructive. Id. Other asserted or unasserted claims can also aid in determining the
`
`claim’s meaning because claim terms are typically used consistently throughout the patent. Id.
`
`Differences among the claim terms can also assist in understanding a term’s meaning. Id. For
`
`example, when a dependent claim adds a limitation to an independent claim, it is presumed that
`
`the independent claim does not include the limitation. Id. at 1314–15.
`
`“[C]laims ‘must be read in view of the specification, of which they are a part.’” Id.
`
`(quoting Markman v. Westview Instruments, Inc., 52 F.3d 967, 979 (Fed. Cir. 1995) (en banc)).
`
`“[T]he specification ‘is always highly relevant to the claim construction analysis. Usually, it is
`
`dispositive; it is the single best guide to the meaning of a disputed term.’” Id. (quoting Vitronics
`
`Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996)); see also Teleflex, Inc. v.
`
`Ficosa N. Am. Corp., 299 F.3d 1313, 1325 (Fed. Cir. 2002). This is true because a patentee may
`
`define his own terms, give a claim term a different meaning than the term would otherwise
`
`possess, or disclaim or disavow the claim scope. Phillips, 415 F.3d at 1316. In these situations,
`
`the inventor’s lexicography governs. Id. Also, the specification may resolve ambiguous claim
`
`terms “where the ordinary and accustomed meaning of the words used in the claims lack
`
`sufficient clarity to permit the scope of the claim to be ascertained from the words alone.”
`
`Teleflex, Inc., 299 F.3d at 1325. But, “‘[a]lthough the specification may aid the court in
`
`interpreting the meaning of disputed claim language, particular embodiments and examples
`
`appearing in the specification will not generally be read into the claims.’” Comark Commc’ns,
`
`3
`
`Petitioner RPX Corporation - Ex. 1049, p. 3
`
`Petitioner Apple Inc. - Exhibit 1015, p.3
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 4 of 31 PageID #: 7524
`
`Inc. v. Harris Corp., 156 F.3d 1182, 1187 (Fed. Cir. 1998) (quoting Constant v. Advanced
`
`Micro-Devices, Inc., 848 F.2d 1560, 1571 (Fed. Cir. 1988)); see also Phillips, 415 F.3d at 1323.
`
`The prosecution history is another tool to supply the proper context for claim construction
`
`because a patent applicant may also define a term in prosecuting the patent. Home Diagnostics,
`
`Inc., v. Lifescan, Inc., 381 F.3d 1352, 1356 (Fed. Cir. 2004) (“As in the case of the specification,
`
`a patent applicant may define a term in prosecuting a patent.”).
`
`Although extrinsic evidence can be useful, it is “‘less significant than the intrinsic record
`
`in determining the legally operative meaning of claim language.’” Phillips, 415 F.3d at 1317
`
`(quoting C.R. Bard, Inc., 388 F.3d at 862). Technical dictionaries and treatises may help a court
`
`understand the underlying technology and the manner in which one skilled in the art might use
`
`claim terms, but technical dictionaries and treatises may provide definitions that are too broad or
`
`may not be indicative of how the term is used in the patent. Id. at 1318. Similarly, expert
`
`testimony may aid a court in understanding the underlying technology and determining the
`
`particular meaning of a term in the pertinent field, but an expert’s conclusory, unsupported
`
`assertions as to a term’s definition is entirely unhelpful to a court. Id. Generally, extrinsic
`
`evidence is “less reliable than the patent and its prosecution history in determining how to read
`
`claim terms.” Id.
`
`Defendants also contend that some claims at issue are invalid for indefiniteness. A claim
`
`is invalid under 35 U.S.C. § 112 ¶ 2 if it fails to particularly point out and distinctly claim the
`
`subject matter that the applicant regards as the invention. The party seeking to invalidate a claim
`
`under 35 U.S.C. § 112 ¶ 2 as indefinite must show by clear and convincing evidence that one
`
`skilled in the art would not understand the scope of the claim when read in light of the
`
`4
`
`Petitioner RPX Corporation - Ex. 1049, p. 4
`
`Petitioner Apple Inc. - Exhibit 1015, p.4
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 5 of 31 PageID #: 7525
`
`specification. Intellectual Prop. Dev., Inc. v. UA-Columbia Cablevision of Westchester, Inc., 336
`
`F.3d 1308, 1319 (Fed. Cir. 2003).
`
`LEVEL OF ORDINARY SKILL IN THE ART
`
`The parties agree that a person of ordinary skill in the art would have a master’s degree in
`
`computer science or computer engineering and approximately two years of experience in
`
`computer networking and computer network security.
`
`CLAIM TERMS
`
`virtual private network
`
`VirnetX proposes “a network of computers which privately communicate with each other
`
`by encrypting traffic on insecure communication paths between the computers.” Defendants
`
`propose the following emphasized additions: “a network of computers which privately and
`
`directly communicate with each other by encrypting traffic on insecure communication paths
`
`between the computers where the communication is both secure and anonymous.”
`
`secure and anonymous
`
`VirnetX proposes the same construction adopted by this Court in Microsoft. See
`
`Microsoft, 2009 U.S. Dist. LEXIS 65667, at *8. Defendants seek to explicitly include the “secure
`
`and anonymous” language that was implicitly included in the Court’s Microsoft construction. See
`
`id. at *16 (“[T]he Court construes ‘virtual private network’ as requiring both data security and
`
`anonymity.”). Just as in Microsoft, the parties here dispute whether a virtual private network
`
`requires anonymity, and the Court hereby incorporates by reference its reasoning in Microsoft.
`
`See id. at *14–17. For the same reasons stated in Microsoft, the Court finds that a virtual private
`
`network requires both data security and anonymity. For clarity, this language is now explicitly
`
`included in the Court’s construction of “virtual private network.”
`
`5
`
`Petitioner RPX Corporation - Ex. 1049, p. 5
`
`Petitioner Apple Inc. - Exhibit 1015, p.5
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 6 of 31 PageID #: 7526
`
`directly
`
`Defendants propose that communication within a virtual private network is “direct” based
`
`on arguments that VirnetX made to the United States Patent and Trademark Office (“PTO”) to
`
`overcome rejections based on the Aventail reference during reexamination of the ‘135 Patent.1
`
`VirnetX provided three reasons that Aventail did not disclose a virtual private network:
`
`First, Aventail has not been shown to demonstrate that computers connected via
`the Aventail system are able to communicate with each other as though they were
`on the same network. . . .
`. . .
`
`Second, according to Aventail, Aventail Connect’s fundamental operation
`is incompatible with users transmitting data that is sensitive to network
`information. . . .
`Third, Aventail has not been shown to disclose a VPN because computers
`connected according to Aventail do not communicate directly with each other.
`
`Docket No. 182 Attach. 16, at 5–7. Defendants argue that VirnetX’s third distinction warrants a
`
`finding that communication over a virtual private network must be direct.
`
`VirnetX argues that its statements during reexamination are not a clear disavowal of
`
`claim scope. Rather, VirnetX contends that it “overcame Aventail on the ground that Aventail
`
`did not teach a VPN at all.” Docket No. 173, at 8. However, the statements made by VirnetX—
`
`particularly points one and three—reveal that the reason Aventail did not disclose a VPN was
`
`because it did not permit direct communication between the source and target computers.
`
`VirnetX further argues that it did not clearly disavow claim scope regarding any one of
`
`the three distinctions between Aventail and a VPN. For support, VirnetX relies on Momentus
`
`Golf, Inc. v. Swingrite Golf Corp., 187 Fed. App’x 981 (Fed. Cir. 2006), which involved a patent
`
`directed to a golf club swing aide. During prosecution of the Momentus Golf patent, the
`
`applicants stated: “A hollow device having 10–25% club head weight cannot meet the
`
`1 The Aventail reference involved a means of secure communication between two clients via an intermediary
`SOCKS server.
`
`6
`
`Petitioner RPX Corporation - Ex. 1049, p. 6
`
`Petitioner Apple Inc. - Exhibit 1015, p.6
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 7 of 31 PageID #: 7527
`
`requirement in applicant’s claims that the center of gravity of the trainer be substantially at the
`
`center of a solid round stock.” Momentus Golf, 187 Fed. App’x at 984 (quoting prosecution
`
`history). The district court held that this statement presented a clear disavowal of golf trainers
`
`with 10–25% club head weight because they would not meet the center of gravity requirement.
`
`Id. at 982. The Federal Circuit agreed that the district court’s interpretation was a fathomable
`
`one. Id. at 983–84. However, it reversed the district court because another interpretation was also
`
`reasonable and still supported the applicant’s distinguishing arguments—that the statement only
`
`clearly disavowed hollow clubs with 10–25% club head weight. Id. at 984 (emphasis added). The
`
`Federal Circuit held that the statement could reasonably be interpreted to disavow (1) clubs with
`
`10–25% club head weight or (2) hollow clubs with 10–25% club head weight. In light of the
`
`competing interpretations, the Federal Circuit determined that there was only a disclaimer of the
`
`more narrow interpretation.
`
`The instant case does not present such an ambiguous statement. VirnetX stated that
`
`“Aventail has not been shown to disclose the VPN . . . for at least three reasons.” Docket No. 182
`
`Attach. 16, at 5. VirnetX then proceeded to independently present and discuss each of the three
`
`distinct reasons that Aventail did not disclose the claimed VPN. See Docket No. 182 Attach. 16,
`
`at 5–6 (discussing the first reason); id. at 6–7 (discussing the second reason); id. at 7 (discussing
`
`the third reason). In Momentus Golf, the applicant combined two potential distinctions in a single
`
`sentence, creating ambiguity as to whether the distinctions were independent or intertwined.
`
`Here, VirnetX expressly stated that there were three bases for distinction. Each of these reasons,
`
`alone, served to distinguish the claimed VPN from the Aventail reference. See Andersen Corp. v.
`
`Fiber Composites, LLC, 474 F.3d 1361, 1374 (Fed. Cir. 2007) (“An applicant’s invocation of
`
`multiple grounds for distinguishing a prior art reference does not immunize each of them from
`
`7
`
`Petitioner RPX Corporation - Ex. 1049, p. 7
`
`Petitioner Apple Inc. - Exhibit 1015, p.7
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 8 of 31 PageID #: 7528
`
`being used to construe the claim language.”). Accordingly, the Court finds that the claimed
`
`“virtual private network” requires direct communication between member computers.2
`
`The Court construes “virtual private network” as “a network of computers which
`
`privately and directly communicate with each other by encrypting traffic on insecure paths
`
`between the computers where the communication is both secure and anonymous.”
`
`virtual private link
`
`VirnetX proposes “a communication
`
`link
`
`that permits computers
`
`to privately
`
`communicate with each other by encrypting traffic on insecure communication paths between the
`
`computers.” Defendants, except the two Aastra entities, propose “a link in a virtual private
`
`network.” The Aastra entities propose “a link in a virtual private network that accomplishes data
`
`security and anonymity through the use of hop tables.”
`
`VirnetX’s proposed construction closely tracks its proposal for “virtual private network,”
`
`replacing “a network of computers which” with “a communication link that permits computers
`
`to.” “Network of computers” implies that the computers are linked together; likewise a
`
`“communication link that permits computers [to communicate]” implies a computer network.
`
`Defendants also note the similarity between VirnetX’s proposed construction of “virtual
`
`private network” and “virtual private link.” Defendants contend that VirnetX’s proposal is
`
`essentially “a communication link that permits computers to VPN.” Tr. of Markman Hr’g 55,
`
`Jan. 5, 2012. As a simplification, Defendants propose “a link in a virtual private network.”
`
`The Aastra entities argue that a virtual private link should be limited to virtual private
`
`network links that use hop tables to achieve data security and anonymity. An embodiment of
`
`2 Defendants stipulated at the Markman hearing that they were not arguing “directly” requires a direct
`electromechanical connection. See Tr. of Markman Hr’g 49–50, Jan. 5, 2012. Rather, Defendants maintained that
`directly requires direct addressability. Thus, routers, firewalls, and similar servers that participate in typical network
`communication do not impede “direct” communication between a client and target computer.
`
`8
`
`Petitioner RPX Corporation - Ex. 1049, p. 8
`
`Petitioner Apple Inc. - Exhibit 1015, p.8
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 9 of 31 PageID #: 7529
`
`claim 13 of the ‘135 Patent, which contains the term “virtual private link,” is depicted in Figure
`
`31. A detailed description of this embodiment is also provided in the specification. See ‘135
`
`Patent cols. 44:14–45:35. This description discusses the use of hopping tables; thus, Aastra
`
`argues that this limitation should be imported into the claims.
`
`The Court rejects Aastra’s attempt to incorporate limitations of a preferred embodiment
`
`into the claims. See Falana v. Kent State Univ., 669 F.3d 1349, 1355 (Fed. Cir. 2012) (cautioning
`
`against importing limitations from a preferred embodiment into the claims). The specification
`
`notes that the use of hopping is one option for accomplishing the data security and anonymity
`
`features. See ‘135 Patent col. 45:10–13 (“Next, signaling server 3101 issues a request to
`
`transport server 3102 to allocate a hopping table (or hopping algorithm or other regime) for the
`
`purpose of creating a VPN with client 3103” (emphasis added)). Thus, the applicants envisioned
`
`alternate methods of implementing data security and anonymity beyond hopping tables, and
`
`importing the hopping limitation into the claims is inappropriate.
`
`The patent specification, in the detailed description of Figure 31, uses the term virtual
`
`private network and virtual private link interchangeably. Compare id. col. 44:37–40 (“When a
`
`packet is received from a known user, the signaling server activates a virtual private link (VPL)
`
`between the user and the transport server . . . .”), with id. col. 45:10–13 (noting that the signaling
`
`server requests the transport server to create a hopping table for the purpose of “creating a VPN
`
`with client 3103.”), and id. col. 45:32–35 (“After a VPN has become inactive for a certain time
`
`period (e.g., one hour), the VPN can be automatically torn down by transport server 3102 or
`
`signaling server 3101.”); see Nystrom v. Trex Co., Inc., 424 F.3d 1136, 1143 (Fed. Cir. 2005)
`
`(“Different terms or phrases in separate claims may be construed to cover the same subject
`
`matter where the written description and prosecution history indicate that such a reading of the
`
`9
`
`Petitioner RPX Corporation - Ex. 1049, p. 9
`
`Petitioner Apple Inc. - Exhibit 1015, p.9
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 10 of 31 PageID #: 7530
`
`terms or phrases is proper.”). Finally, VirnetX’s and Defendants’ proposed constructions of
`
`virtual private link are very similar to their proposed constructions for virtual private network.
`
`Accordingly, the Court construes “virtual private link” as “a virtual private network as
`
`previously defined.”
`
`secure communication link
`
`VirnetX proposes “an encrypted communication link.” Defendants propose “virtual
`
`private network communication link.” The parties in Microsoft agreed that this term, as used in
`
`the ‘759 Patent, did not require construction because the claims themselves provide a definition
`
`of the term. Microsoft, 2009 U.S. Dist. LEXIS 65667, at *43. For instance, claim 1 states: “the
`
`secure communication link being a virtual private network communication link over the
`
`computer network.” ‘759 Patent col. 57:20–22. Here, the parties also agree that, as to the ‘759
`
`Patent, the term means “virtual private network communication link.” However, the claims of the
`
`‘504 and ‘211 Patents use this term without further defining it. Thus, the parties dispute the
`
`construction of the term as used in the ‘504 and ‘211 Patents.
`
`VirnetX contends that “secure” means the link uses some form of data encryption,
`
`highlighting the following passage from the ‘504 Patent specification: “Data security is usually
`
`tackled using some form of data encryption.” ‘504 Patent col. 1:55–56. VirnetX argues that the
`
`inventors would have used the term “virtual private network communication link” had it desired
`
`to limit “secure communication link” to that interpretation. VirnetX further argues Defendants’
`
`proposal improperly imports a limitation from the preferred embodiment, which discloses a
`
`secure communication link that is also a virtual private network communication link. VirnetX
`
`states that “Defendants fail to explain why a secure communication link must always be a virtual
`
`private network communication link for all possible embodiments of the claims.” Docket No.
`
`10
`
`Petitioner RPX Corporation - Ex. 1049, p. 10
`
`Petitioner Apple Inc. - Exhibit 1015, p.10
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 11 of 31 PageID #: 7531
`
`192, at 4. Finally, VirnetX argues that it did not narrow the interpretation of “secure
`
`communication link” during the prosecution of the ‘504 and ‘211 Patents.
`
`Defendants argue that secure communication link is defined in the Summary of the
`
`Invention: “The secure communication link is a virtual private network communication link over
`
`the computer network.” ‘504 Patent col. 6:61–62. Defendants further argue that the detailed
`
`description of the invention also uses the terms “secure communication link” and “virtual private
`
`network communication link” synonymously. Defendants also highlight VirnetX’s arguments
`
`regarding “secure communication link” while prosecuting U.S. Patent No. 8,051,181 (“the ‘181
`
`patent”), a related patent that is not at issue in the instant case.
`
`The ‘181 Patent is related to the patents-in-suit; it is a division of a continuation-in-part
`
`of the ‘783 Application that serves as an ancestor application for all of the patents-in-suit. The
`
`Federal Circuit has held that arguments to the PTO regarding one patent application are
`
`applicable to related patent applications. See Microsoft Corp. v. Multi-Tech Sys., Inc., 357 F.3d
`
`1340, 1349 (Fed. Cir. 2004) (“[T]he prosecution history of one patent is relevant to an
`
`understanding of the scope of a common term in a second patent stemming from the same parent
`
`application.”). The Federal Circuit has also held that arguments regarding a later filed application
`
`may be applicable to a previously filed application. See Verizon Servs. Corp. v. Vonage Holdings
`
`Corp., 503 F.3d 1295, 1307 (Fed. Cir. 2007) (rejecting the argument that a disclaimer should not
`
`apply because it occurred after the patent under consideration had issued). Here, the ‘181 Patent
`
`issued after all of the patents-in-suit. Its application was filed later than the applications for the
`
`patents-in-suit except for the ‘211 Patent, which was filed approximately six months earlier.
`
`When prosecuting the ‘181 Patent, VirnetX distinguished the Aventail reference from the
`
`“secure communication link” limitation using arguments nearly identical to those discussed
`
`11
`
`Petitioner RPX Corporation - Ex. 1049, p. 11
`
`Petitioner Apple Inc. - Exhibit 1015, p.11
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 12 of 31 PageID #: 7532
`
`earlier regarding Aventail and the “virtual private network” term. VirnetX argued that Aventail
`
`failed to disclose a “secure communication link” for the same three reasons asserted in the ‘135
`
`reexamination. Compare Docket No. 182 Attach. 16, at 5–7 (arguments regarding “virtual
`
`private network” and Aventail), with Docket No. 202 Attach. 1, at 6–8 (arguments regarding
`
`“secure communication link” and Aventail). Therefore, for the same reasons stated earlier
`
`regarding “virtual private network,” a “secure communication link” also requires direct
`
`communication between its nodes.
`
`“Secure communication link” was originally used in the claims of the ‘759 Patent, which
`
`was also at issue in Microsoft. There, the parties agreed that it did not require construction
`
`because the claim language itself defined the term as “being a virtual private network
`
`communication link.” ‘759 Patent col. 57:20–22. However, the later-filed applications that issued
`
`as the ‘504 and ‘211 Patents removed this defining language from the claims. Accordingly the
`
`term is not so limited in the ‘504 and ‘211 Patents as in the ‘759 Patent.
`
`Defendants argue that the Summary of the Invention defined a secure communication
`
`link as a virtual private network communication link. However, this discussion in the Summary
`
`of the Invention relates to a particular preferred embodiment and opens as follows:
`
`According to one aspect of the present invention, a user can conveniently
`establish a VPN using a “one-click” . . . technique without being required to enter
`[information] for establishing a VPN. The advantages of the present invention are
`provided by a method for establishing a secure communication link . . . .
`
`‘504 Patent col. 6:36–42. Thus, the advantage of being able to seamlessly establish a one-click
`
`VPN is provided by “a method for establishing a secure communication link.” The description
`
`continues by describing the details of an embodiment that realizes this advantage. See id. cols.
`
`6:43–7:10 (describing the one-click embodiment). It is within this description of the preferred
`
`embodiment that the specification acknowledges that the “secure communication link is a virtual
`
`12
`
`Petitioner RPX Corporation - Ex. 1049, p. 12
`
`Petitioner Apple Inc. - Exhibit 1015, p.12
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 13 of 31 PageID #: 7533
`
`private network communication link.” Id. col. 6:61–63. The patentee is not acting as his own
`
`lexicographer here; rather, he is describing a preferred embodiment. The claims and specification
`
`of the ‘504 and ‘211 Patents reveal that the patentee made a conscious decision to remove the
`
`virtual private network limitation originally present in the ‘759 Patent claims. Thus, secure
`
`communication link shall be interpreted without this limitation in the ‘504 and ‘211 Patents.
`
`VirnetX proposes that a secure communication link is an encrypted link. However, claim
`
`28 of the ‘504 Patent3 covers “[t]he system of claim 1, wherein the secure communication link
`
`uses encryption.” ‘504 Patent col. 57:17–18. VirnetX’s proposal seeks to import a limitation
`
`from dependent claim 28 into independent claim 1, and this violates the doctrine of claim
`
`differentiation. See Curtiss-Wright Flow Control Corp. v. Velan, Inc., 438 F.3d 1374, 1380 (Fed.
`
`Cir. 2006) (“‘[C]laim differentiation’ refers to the presumption that an independent claim should
`
`not be construed as requiring a limitation added by a dependent claim.”). The specification notes
`
`that “[d]ata security is usually tackled using some form of data encryption.” ‘504 Patent col.
`
`1:55–56 (emphasis added). Therefore, encryption is not the only means of addressing data
`
`security. Accordingly, a secure communication link is one that provides data security, which
`
`includes encryption.
`
`The Court construes “secure communication link” as “a direct communication link that
`
`provides data security.”4
`
`3 Claim 28 of the ‘211 Patent is similar.
`4 As the Court discussed earlier, the ‘759 Patent claims further limit the secure communication link recited therein.
`This construction does not contradict these provisions of the ‘759 claims, which limit the secure communication link
`there to a virtual private network communication link. Thus, as a practical matter, the “secure communication link”
`recited in the ‘759 Patent claims is a “virtual private network communication link.”
`
`13
`
`Petitioner RPX Corporation - Ex. 1049, p. 13
`
`Petitioner Apple Inc. - Exhibit 1015, p.13
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 14 of 31 PageID #: 7534
`
`domain name service
`
`VirnetX proposes “a lookup service that returns an IP address for a requested domain
`
`name,” adopting the Court’s previous construction of this term in Microsoft. Defendants propose
`
`to append “to the requester” to VirnetX’s proposed construction.
`
`VirnetX argues that Defendants’ proposal incorporates an extraneous limitation. Further,
`
`VirnetX provides an expert declaration stating that one of skill in the art, after reading the
`
`specification, would understand that a domain name service does not necessarily return the
`
`requested IP address to the requester. See Docket No. 173 Attach. 17 ¶¶ 7–8 (stating that in the
`
`context of a DNS proxy, the IP address may be returned to the original requesting client, the
`
`proxy, or both). VirnetX also argues that the specification envisions a domain name service that
`
`does not always return an address to the requester. For instance, the specification states:
`
`According to certain aspects of the invention, a specialized DNS server traps DNS
`requests and, if the request is from a special type of user . . . , the server does not
`return the true IP address of the target node, but instead automatically sets up a
`virtual private network between the target node and the user.
`
`‘135 Patent cols. 37:63–38:2. Defendants argue that VirnetX ignores the implicit meaning of the
`
`Court’s Microsoft construction by arguing that a domain name service does not necessarily
`
`return the requested IP address to the requester.
`
`VirnetX’s expert explains that “in one mode, the domain name request can be received by
`
`a DNS proxy (or DNS proxy module), which, in turn, may forward the request to a DNS function
`
`that can return an IP address.” Docket No. 173 Attach. 17 ¶ 8. Thus, VirnetX argues, a domain
`
`name request may cause an IP address to be returned “to the client, or to a DNS proxy . . . , or
`
`both.” Id. VirnetX’s expert is effectively describing a scenario detailed in the ‘135 Patent and
`
`cited above by VirnetX. This scenario is further described in detail in the specification and
`
`depicted in Figure 26. See ‘135 Patent col. 38:13–42 (describing the operation of the system
`
`14
`
`Petitioner RPX Corporation - Ex. 1049, p. 14
`
`Petitioner Apple Inc. - Exhibit 1015, p.14
`
`
`
`Case 6:10-cv-00417-LED Document 266 Filed 04/25/12 Page 15 of 31 PageID #: 7535
`
`depicted in Figure 26). VirnetX asserts that Defendants’ proposed construction precludes this
`
`preferred embodiment.
`
`Contrary to VirnetX’s argument, Defendants’ proposed limitation does not preclude a
`
`preferred embodiment. The “specialized” or “modified” DNS server referenced in the
`
`specification is shown as 2602 in Figure 26. This modified DNS server contains a DNS proxy
`
`function and a standard DNS server function. Requests for non-secure sites are passed through to
`
`the DNS server, and an IP address is returned to the requesting client. In this case, two separate
`
`domain name requests are effectively being made: (1) between the client computer 2601 and the
`
`modified DNS server 2602; and (2) between the DNS Proxy 2610 and the DNS Server 2609. If
`
`the original client request is for a secure site, then the DNS Proxy 2610 establishes a VPN
`
`connection between the client and the secure site. The specification explains the final stages of
`
`this process:
`
`Thereafter, DNS proxy 2610 returns to user computer 2601 the resolved address
`passed to it by the gatekeeper (this address could be different from the actual
`target computer) 2604, preferably using a secure administrative VPN. The address
`that is returned need not be the actual address of the destination computer.
`
`Id. col. 38:36–42. The DNS Proxy 2610, operating as an internal component of the modified
`
`DNS server 2602, returns an address to the requestor, the client computer 2601. Thus, viewing
`
`the modified DNS server 2602 as a black box, it returned an address