Case 6:07-cv-00080-LED Document 246 Filed 07/30/09 Page 1 of 35
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`IN THE UNITED STATES DISTRICT COURT
`FOR THE EASTERN DISTRICT OF TEXAS
`TYLER DIVISION
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`CASE NO. 6:07 CV 80
`PATENT CASE
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`§§§§§
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`§
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`§§§§
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`VIRNETX, INC.
`
`Plaintiff
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`vs.
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`MICROSOFT CORPORATION
`
`Defendant
`
`MEMORANDUM OPINION
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`This claim construction opinion interprets the disputed terms in U.S. Patent Nos. 6,502,135
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`(“the ‘135 patent”); 6,839,759 (“the ‘759 patent”); and 7,188,180 (“the ‘180 patent”). Appendix A
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`contains the disputed terms, as they appear in the asserted claims of these patents. Appendix B
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`contains a chart summarizing the Court’s constructions.
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`BACKGROUND
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`Plaintiff VirnetX, Inc. (“VirnetX”) accuses Microsoft Corporation (“Microsoft”) of infringing
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`claims of the ‘135, ‘759, and ‘180 patents. The ‘135 patent discloses a method of transparently
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`creating a virtual private network between a client computer and a target computer. The ‘759 patent
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`discloses a method for establishing a VPN without a user entering user identification information.
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`The ‘759 patent is related to the ‘135 patent through other continuation-in-part applications/patents.
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`The ‘180 patent discloses a method for establishing a VPN using a secure domain name service. The
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`‘180 patent is related to the ‘135 patent as a divisional patent of continuation-in-part
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`applications/patents of the ‘135 patent. The ‘759 and ‘180 patents share the same specification.
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`1
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`VIRNETX EXHIBIT 2033
`Mangrove v. VirnetX
`Trial IPR2015-01046
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`APPLICABLE LAW
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`“It is a ‘bedrock principle’ of patent law that ‘the claims of a patent define the invention to
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`which the patentee is entitled the right to exclude.’” Phillips v. AWH Corp., 415 F.3d 1303, 1312
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`(Fed. Cir. 2005) (en banc) (quoting Innova/Pure Water Inc. v. Safari Water Filtration Sys., Inc., 381
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`F.3d 1111, 1115 (Fed. Cir. 2004)). In claim construction, courts examine the patent’s intrinsic
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`evidence to define the patented invention’s scope. See id.; C.R. Bard, Inc. v. U.S. Surgical Corp.,
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`388 F.3d 858, 861 (Fed. Cir. 2004); Bell Atl. Network Servs., Inc. v. Covad Commc’ns Group, Inc.,
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`262 F.3d 1258, 1267 (Fed. Cir. 2001). This intrinsic evidence includes the claims themselves, the
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`specification, and the prosecution history. See Phillips, 415 F.3d at 1314; C.R. Bard, Inc., 388 F.3d
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`at 861. Courts give claim terms their ordinary and accustomed meaning as understood by one of
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`ordinary skill in the art at the time of the invention in the context of the entire patent. Phillips, 415
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`F.3d at 1312 13; Alloc, Inc. v. Int’l Trade Comm’n, 342 F.3d 1361, 1368 (Fed. Cir. 2003).
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`The claims themselves provide substantial guidance in determining the meaning of particular
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`claim terms. Phillips, 415 F.3d at 1314. First, a term’s context in the asserted claim can be very
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`instructive. Id. Other asserted or unasserted claims can also aid in determining the claim’s meaning
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`because claim terms are typically used consistently throughout the patent. Id. Differences among
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`the claim terms can also assist in understanding a term’s meaning. Id. For example, when a
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`dependent claim adds a limitation to an independent claim, it is presumed that the independent claim
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`does not include the limitation. Id. at 1314 15.
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`“[C]laims ‘must be read in view of the specification, of which they are a part.’” Id. (quoting
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`Markman v. Westview Instruments, Inc., 52 F.3d 967, 979 (Fed. Cir. 1995) (en banc)). “[T]he
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`specification ‘is always highly relevant to the claim construction analysis. Usually, it is dispositive;
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`it is the single best guide to the meaning of a disputed term.’” Id. (quoting Vitronics Corp. v.
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`Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996)); Teleflex, Inc. v. Ficosa N. Am. Corp., 299
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`F.3d 1313, 1325 (Fed. Cir. 2002). This is true because a patentee may define his own terms, give
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`a claim term a different meaning than the term would otherwise possess, or disclaim or disavow the
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`claim scope. Phillips, 415 F.3d at 1316. In these situations, the inventor’s lexicography governs.
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`Id. Also, the specification may resolve ambiguous claim terms “where the ordinary and accustomed
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`meaning of the words used in the claims lack sufficient clarity to permit the scope of the claim to be
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`ascertained from the words alone.” Teleflex, Inc., 299 F.3d at 1325. But, “‘[a]lthough the
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`specification may aid the court in interpreting the meaning of disputed claim language, particular
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`embodiments and examples appearing in the specification will not generally be read into the
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`claims.’” Comark Commc’ns, Inc. v. Harris Corp., 156 F.3d 1182, 1187 (Fed. Cir. 1998) (quoting
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`Constant v. Advanced Micro-Devices, Inc., 848 F.2d 1560, 1571 (Fed. Cir. 1988)); see also Phillips,
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`415 F.3d at 1323. The prosecution history is another tool to supply the proper context for claim
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`construction because a patent applicant may also define a term in prosecuting the patent. Home
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`Diagnostics, Inc., v. Lifescan, Inc., 381 F.3d 1352, 1356 (Fed. Cir. 2004) (“As in the case of the
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`specification, a patent applicant may define a term in prosecuting a patent.”).
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`Although extrinsic evidence can be useful, it is “‘less significant than the intrinsic record in
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`determining the legally operative meaning of claim language.’” Phillips, 415 F.3d at 1317 (quoting
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`C.R. Bard, Inc., 388 F.3d at 862). Technical dictionaries and treatises may help a court understand
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`the underlying technology and the manner in which one skilled in the art might use claim terms, but
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`technical dictionaries and treatises may provide definitions that are too broad or may not be
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`indicative of how the term is used in the patent. Id. at 1318. Similarly, expert testimony may aid
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`a court in understanding the underlying technology and determining the particular meaning of a term
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`in the pertinent field, but an expert’s conclusory, unsupported assertions as to a term’s definition is
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`entirely unhelpful to a court. Id. Generally, extrinsic evidence is “less reliable than the patent and
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`its prosecution history in determining how to read claim terms.” Id.
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`CONSTRUCTION OF DISPUTED TERMS IN THE ‘135 PATENT1, 2
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`“virtual private network”
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`The ‘135 patent, claims 1 and 10; the ‘759 patent, claims 1 and 16; and the ‘180 patent,
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`claims 1, 17, and 33 contain the term “virtual private network” (“VPN”). VirnetX contends that
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`“virtual private network” means “a network of computers capable of privately communicating with
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`each other by encrypting traffic on insecure communication paths between the computers, and which
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`is capable of expanding to include additional computers and communication paths.” Microsoft
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`contends that “virtual private network” means “a network implemented by encapsulating an
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`encrypted IP packet within another IP packet (that is, tunneling) over a shared networking
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`infrastructure.” The parties dispute whether the “FreeS/WAN” dictionary may be used to construe
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`“virtual private network,” whether VirnetX’s proposed construction is overly broad, whether “virtual
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`private network” requires anonymity, and whether IP tunneling is a limitation on “virtual private
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`network.” In light of intrinsic and extrinsic evidence, the Court construes “virtual private network”
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`as “a network of computers which privately communicate with each other by encrypting traffic on
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`insecure communication paths between the computers.”
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`1
`While this heading states “Construction of Disputed Terms in the ‘135 Patent,” the claim terms addressed
`under this heading may also be found in the other asserted patents. This also applies to subsequent headings.
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`2
`Citations to the patents will not include the U.S. patent numbers to maintain brevity. Unless otherwise
`stated, these citations are of the U.S. patent numbers indicated in the heading that the citation falls under.
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`The ‘135 patent does not provide an explicit definition for “virtual private network.”
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`However, the ‘135 patent uses “virtual private network” in ways that are consistent with a “virtual
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`private network” being “a network of computers which privately communicate with each other by
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`encrypting traffic on insecure communication paths between the computers.” The specification
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`discusses a VPN in the context of connecting and communicating between nodes. For instance, the
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`specification states, “In a second mode referred to as ‘promiscuous per VPN’ mode, a small set of
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`fixed hardware addresses are used, with a fixed source/destination hardware address used for all
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`nodes communicating over a virtual private network.” Col. 23:11-14. This excerpt shows that the
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`‘135 invention includes nodes (computers) communicating over a virtual private network.
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`Furthermore, the claims and specification discuss a VPN in the context of private
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`communication on insecure communication paths. Claim 1 states “A method of transparently
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`creating a virtual private network (VPN) between a client computer and a target computer” and then
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`states the steps of accomplishing this method including “requesting access to a secure web site.”
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`Col. 47:20-22, 30-31. Thus, claim 1 associates a “virtual private network” with “security.” Also,
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`the specification states, “If the user is not authorized to access the secure site, then a ‘host unknown’
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`message is returned (step 2705). If the user has sufficient security privileges, then in step 2706 a
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`secure VPN is established between the user’s computer and the secure target site.” Col. 39:21:25.
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`This excerpt shows how a “virtual private network” establishes a secure connection between nodes
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`where security may not otherwise exist. Thus, the claim language and the specification are
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`consistent with construing a “virtual private network” as “a network of computers which privately
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`communicate with each other by encrypting traffic on insecure communication paths between the
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`computers.”
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`Extrinsic evidence also supports this construction. The Wiley Electrical and Electronics
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`Engineering Dictionary defines a “virtual private network” as
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`A network which has the appearance, functionality, and security of a private network,
`but which is configured within a public network, such as the Internet. The use of a
`public infrastructure while ensuring privacy using measures such as encryption and
`tunneling protocols, helps provide the security of a private network at a cost similar
`to that of a public network.
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`WILEY ELECTRICAL AND ELECTRONICS ENGINEERING DICTIONARY 842 (2004) (published by the
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`IEEE Press). This dictionary definition describes a network that has attributes of a private network
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`but runs on a public network. The dictionary definition further states that encryption may be used
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`to achieve privacy. The Court’s construction is in line with this definition. All pertinent aspects of
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`the Court’s construction are explicitly found in the dictionary definition except for “insecure
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`communication paths,” which simply corresponds to the dictionary definition’s reference to “a public
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`network.” Thus, the Court’s construction is in accord with the dictionary definition.
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`Also, the ‘135 patent refers to the “FreeS/WAN” project in the specification. The
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`specification explains that the “FreeS/WAN” project is developing a conventional scheme that
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`provides secure virtual private networks over the Internet. Col. 37:50-58. The “FreeS/WAN”
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`project defines “virtual private network” as “a network which can safely be used as if it were private,
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`even though some of its communication uses insecure connections. All traffic on those connections
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`is encrypted.” “FreeS/WAN” Glossary 24-25, Pl. Br. (Docket No. 194) Ex. 6. The Court’s
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`construction is consistent with this definition.3
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`3
`The Court’s construction largely adopts VirnetX’s proposal. However, this construction excludes
`VirnetX’s proposed language regarding the ability of a virtual private network to expand. VirnetX proposes this
`language to account for the possibility of including additional computers and communication paths in a virtual
`private network. Pl.’s Br. 6. The Court’s construction does not limit a “virtual private network” to any particular
`number of computers or communication paths. Thus, VirnetX’s proposed language is superfluous. Accordingly, the
`Court’s construction accounts for the possibility of additional computers or communication paths.
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`Microsoft contends that the “FreeS/WAN” glossary is not an explicit definition of “virtual
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`private network” and thus is not persuasive. Microsoft argues that the ‘135 patent’s reference to the
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`“FreeS/WAN” project is made only to describe the prior art and not to define “virtual private
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`network.” However, the specification explains that the “FreeS/WAN” project has been developing
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`an implementation of one conventional scheme that provides secure virtual private networks over
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`the Internet. Col. 37:50-58. Also, the applicant disclosed the “FreeS/WAN” project as prior art.
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`See Def.’s Br. (Docket No. 201) Exs. M-O. While these references to the “FreeS/WAN” project do
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`not explicitly define “virtual private network,” they at least point to extrinsic evidence that can be
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`considered in construing “virtual private network.” Thus, the Court may consider the “FreeS/WAN”
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`project/glossary as extrinsic evidence for construing “virtual private network.”
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`Microsoft also contends that even if the “FreeS/WAN” glossary offers an acceptable
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`definition for “virtual private network,” portions of the “FreeS/WAN” glossary definition show that
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`VirnetX’s proposed construction is overly broad. Microsoft cites the portion of the “FreeS/WAN”
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`glossary definition for “virtual private networks” that states “IPSEC [Internet Protocol Security] is
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`not the only technique available for building VPNs, but it is the only method defined by RFCs
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`[Request for Comments, Internet documents
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`some of which are informative while others are
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`standards] and supported by many vendors. VPNs [virtual private networks] are by no means the
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`only thing you can do with IPSEC, but they may be the most important application for many users.”
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`Def.’s Br. (Docket No. 201) at 10; “FreeS/WAN” Glossary 25, Pl. Br. (Docket No. 194) Ex. 6.
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`Microsoft points out that IPSEC is the only method defined by RFCs and supported by many
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`vendors. Microsoft argues that this narrow language shows that the “FreeS/WAN” glossary does not
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`identify Secure Sockets Layer (“SSL”) or Transport Layer Security (“TLS”) as methods for building
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`“virtual private networks.” Microsoft then argues that VirnetX’s proposed construction is overly
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`broad because it allows for a network using SSL and TLS. However, Microsoft’s cited excerpt is
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`an ancillary portion of the “virtual private network” definition and is set apart in a different
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`paragraph from the primary portion of the definition. See “FreeS/WAN” Glossary 24-25, Pl. Br.
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`(Docket No. 194) Ex. 6. Also, Microsoft selectively asserts that IPSEC is the only method defined
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`by RFCs and supported by many vendors and ignores that its cited excerpt states that “IPSEC is not
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`the only technique available for building VPNs.” Thus, Microsoft’s cited excerpt does not support
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`that the “FreeS/WAN” glossary restricts “virtual private network” to IPSEC.
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`Microsoft also contends that VirnetX’s proposed construction suggests that the “virtual
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`private network” achieves only data security when it should include both data security and
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`anonymity. Microsoft is correct that “private” in “virtual private networks” means both data security
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`and anonymity. The specification supports this interpretation. The Background of the Invention
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`section states “[a] tremendous variety of methods have been proposed and implemented to provide
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`security and anonymity for communications over the Internet.” Col. 1:15-17. This section further
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`describes data security as being “immune to eavesdropping” and states “[d]ata security is usually
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`tackled using some form of data encryption” and anonymity as “preventing[ing] an eavesdropper
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`from discovering that terminal 100 is in communication with terminal 110.” Col. 1:23-25, 38-39,
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`27-28. This language suggests that the claimed invention will achieve both data security and
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`anonymity because it prefaces the Detailed Description of the Invention section, which describes a
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`method of creating a virtual private network.
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`Indeed, the descriptions of the invention later indicate that “private” in “virtual private
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`network” means data security and anonymity. The Detailed Description of the Invention, Further
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`Extensions section describes a mode of the invention as being able to “reduce the amount of
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`overhead involved in checking for valid frames” while allowing “IP addresses . . . [to] still be hopped
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`as before for secure communication within the VPN.” Col. 23:20-25 (emphasis added). The
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`“anonymity” feature of a VPN can be handled by the Tunneled Agile Routing Protocol (“TARP”),
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`which executes “address hopping.” See Col. 2:66-3:17; see Col. 5:49-64. Thus, the language “still
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`be hopped” indicates that the modifications of the invention retain the anonymity feature of the
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`“virtual private network.” Accordingly, the Court construes “virtual private network” as requiring
`4
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`both data security and anonymity.
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`Finally, Microsoft contends that “virtual private network” requires IP tunneling. Microsoft
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`argues that the intrinsic evidence shows that TARP and IPSEC are two ways of obtaining anonymity
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`in a virtual private network. Microsoft then argues that tunneling is required to achieve anonymity
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`when TARP, IPSEC, or any other means is employed to achieve anonymity. The Court first and
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`foremost considers the intrinsic evidence. The claims do not assert “tunneling” as a limitation nor
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`has Microsoft pointed to any type of limitation in the specification. Microsoft’s citations to the
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`Background of the Invention section only state explanations of how TARP works and does not use
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`any limiting language. See Col. 3:5-18, 19-20, 58-60. Furthermore, Microsoft’s citation to the
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`Detailed Description of the Invention, Further Extensions section only refers to a preferred
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`implementation of the virtual private network, stating “The VPN is preferably implemented using
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`4
`While the specification states that this mode of the invention “[o]f course . . . compromises the anonymity
`of the VPNs,” this only means that those outside the VPN can discover the VPN and does not mean that the
`anonymity of the users within the VPN is compromised. This is clear from the example that follows the
`“compromising anonymity of the VPN” statement: “(i.e., an outsider can easily tell what traffic belongs in which
`VPN, though he cannot correlate it to a specific machine/person).” Col. 23:25 28 (emphasis added). Thus, the
`specification is consistent with construing a “virtual private network” as achieving both data security and anonymity.
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`the IP address ‘hopping’ features of the basic invention described above, such that the true identity
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`of the two nodes cannot be determined even if packets during the communication are intercepted.”
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`Col. 38:2-6. Again, this excerpt does not include any limiting language and in fact expressly uses
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`the non-limiting language “preferably.” Accordingly, “virtual private network” is not limited to IP
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`tunneling, and the Court construes “virtual private network” as “a network of computers which
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`privately communicate with each other by encrypting traffic on insecure communication paths
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`between the computers.”
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`“transparently creating [creates] a virtual private network”
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`The ‘135 patent, claims 1 and 10 contain the phrase “transparently creating [creates] a virtual
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`private network.” The parties dispute whether “transparently creating a virtual private network” in
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`the preamble is limiting and whether “transparently” refers to not involving a user or not involving
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`the client and target computers in creating a virtual private network. VirnetX contends that this
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`phrase means “a user need not be involved in creating a virtual private network.” Microsoft
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`contends that the phrase does not require construction and alternatively that the phrase means
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`“creating a virtual private network (VPN) without the client or target computer involved in
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`requesting such creation.”
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`“Transparently creating a virtual private network” in the preamble is not a limitation because
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`“transparently” does not add meaning to claims 1 and 10. “A preamble limits the invention if it
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`recites essential structure or steps, or if it is ‘necessary to give life, meaning, and vitality’ to the
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`claim. Conversely, a preamble is not limiting ‘where a patentee defines a structurally complete
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`invention in the claim body and uses the preamble only to state a purpose or intended use for the
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`invention.’” Catalina Mktg. Int’l, Inc. v. Coolsavings.com, Inc., 289 F.3d 801, 808 (Fed. Cir. 2002)
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`10
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`(citations omitted). If a preamble “is reasonably susceptible to being construed to be merely
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`duplicative of the limitations in the body of the claim (and was not clearly added to overcome a
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`rejection), we do not construe it to be a separate limitation.” Symantec Corp. v. Computer Assocs.
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`Int’l, Inc., 522 F.3d 1279, 1288-89 (Fed. Cir. 2008). “Transparently” is merely descriptive of what
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`is found in steps (2) and (3) of claim 1. As discussed below, those steps require that a user is not
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`involved in creating a VPN. This requirement corresponds to the meaning of “transparently” as
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`described in the specification, which states that creating a VPN “is preferably performed
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`transparently to the user (i.e., the user need not be involved in creating the secure link).” Col. 39:28-
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`29. Thus, “transparently” is merely duplicative of what is found in the body of claim 1. As a result,
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`the preamble is not a limitation. Accordingly, “transparently” does not require construction.
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`“Domain Name Service”
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`The ‘135 patent, claims 1 and 10 and the ‘180 patent, claims 1, 17, and 33 contain the term
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`“Domain Name Service” (“DNS”). VirnetX contends that “Domain Name Service” means “a
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`service that receives requests for computer network addresses corresponding to domain names, and
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`which provides responses.” Microsoft contends that “Domain Name Service” means “the
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`conventional lookup service defined by the Internet Engineering Task Force (“IETF”) that returns
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`the IP address of a requested computer or host.” The parties dispute whether “Domain Name
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`Service” is limited by the definition given in the IETF that defines Domain Name Service as the
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`conventional scheme or if it more broadly includes both conventional and modified Domain Name
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`Service that is described in the specification.
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`The specification’s description of DNS is consistent with construing DNS as “a lookup
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`service that returns an IP address for a requested domain name.” The specification states
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`Conventional Domain Name Servers (DNSs) provide a look-up function that returns
`the IP address of a requested computer or host. For example, when a computer user
`types in the web name “Yahoo.com,” the user’s web browser transmits a request to
`a DNS, which converts the name into a four-part IP address that is returned to the
`user’s browser and then used by the browser to contact the destination web site.
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`Col. 37:22-29. According to this excerpt, a DNS “provides a look-up function” and “returns the IP
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`address of a requested computer or host.” A “computer or host” includes domain names as
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`exemplified by the specification’s reference to “Yahoo.com” and “destination web site” as “a
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`requested computer or host.” Accordingly, the Court construes “DNS” as “a lookup service that
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`returns an IP address for a requested domain name.”5
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`“domain name”
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`The ‘135 patent, claims 1 and 10 and the ‘180 patent, claims 1, 17, and 33 contain the term
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`“domain name.” VirnetX contends that “domain name” means “a series of characters that
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`corresponds to an address of a computer or group of computers that is to be sent to a domain name
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`service (DNS).” Microsoft contends that “domain name” means “a hierarchical name for a computer
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`(such as www.utexas.edu) that the Domain Name Service converts into an IP address.” The parties
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`dispute whether “domain name” can correspond to a group of computers or only a single computer,
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`whether “domain name” is a hierarchical name for a computer, whether “domain name” is limited
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`to web site names, and whether “domain name” is limited to a computer name being converted into
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`an IP address.
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`The claims themselves describe “domain name.” Claim 1 states “a Domain Name Service
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`(DNS) request that requests an IP address corresponding to a domain name associated with the target
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`computer.” Col. 47:23-26. Also, claim 10 states “a DNS proxy server that receives a request from
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`5
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`See below for the Court’s construction of “domain name.”
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`the client computer to look up an IP address for a domain name.” Col. 48:6-7. In both claim 1 and
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`claim 10 an IP address corresponds to a domain name. Thus, the domain name corresponds to an
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`IP address. Accordingly, the Court construes “domain name” as “a name corresponding to an IP
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`address.”
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`VirnetX proposes that “domain name” corresponds to a group of computers (IP addresses)
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`or a single computer because claims 1 and 10 of the ‘135 patent refer to IP address using the
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`indefinite article “an.” The Federal Circuit has stated,
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`An indefinite article ‘a’ or ‘an’ in patent parlance carries the meaning of ‘one or
`more’ in open-ended claims containing the transitional phrase ‘comprising.’” That
`“a” or “an” can mean “one or more” is best described as a rule, rather than merely as
`a presumption or even a convention. The exceptions to [the “indefinite article”] rule
`are extremely limited: a patentee must “evince [ ] a clear intent” to limit “a” or “an”
`to “one.” The subsequent use of definite articles “the” or “said” in a claim to refer
`back to the same claim term does not change the general plural rule, but simply
`reinvokes that non-singular meaning. An exception to the general rule that “a” or
`“an” means more than one only arises where the language of the claims themselves,
`the specification, or the prosecution history necessitate a departure from the rule.
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`Baldwin Graphic Sys., Inc. v. Siebert, Inc., 512 F.3d 1338, 1342-43 (Fed. Cir. 2008) (citations
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`omitted). Claims 1 and 10 of the ‘135 patent are open-ended construction claims using the word
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`“comprising” and use the indefinite article “an” to refer to “IP address.” See Col. 47:20-26; see Col.
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`48:3-7. By the “one or more” rule, these claims allow for one or more IP addresses. Any subsequent
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`use of the definite article “the” to refer to “IP address” simply refers back to the previously used “IP
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`address” and thus reinvokes the non-singular meaning. See Col. 47:39-40; see Col. 48:8. Microsoft
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`does not assert any evidence to show that an exception to the “one or more” rule exists. Thus, there
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`may be more than one IP address, and thus more than one computer, that corresponds with the
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`domain name. This would allow for a situation where the IP address that corresponds to the domain
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`name is not the IP address of the target computer. See Col. 38:23-42. Accordingly, “domain name”
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`can correspond to more than one computer.
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`Microsoft contends that the patents limit “domain name” to a hierarchical name for a
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`computer under traditional hierarchical DNS format. However, Microsoft relies largely on extrinsic
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`evidence
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`including expert testimony and Microsoft’s own technology tutorial
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`to support its
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`contentions, which does not carry great weight in light of the fact that claim language provides
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`guidance on the meaning of “domain name.” Also, where Microsoft uses intrinsic evidence for
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`support, Microsoft only refers to non-limiting language from the specification. For instance,
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`Microsoft suggests that the examples used in the specification for domain names, which include
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`“Yahoo.com” and “Target.com,” show that the patents use “domain name” in its traditional
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`hierarchical DNS format. Microsoft further suggests that “domain name” is limited to a traditional
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`hierarchical name because the patents do not provide a single example of “domain name” that is not
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`written in traditional hierarchical DNS format. However, Microsoft argues only the presence and
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`absence of examples rather than any enforceable language of limitation. The specification’s
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`disclosure or omission of examples does not create limitations on claims. Accordingly, Microsoft
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`does not offer sufficient support for limiting “domain name” to a hierarchical name for a computer.
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`Microsoft also contends that the patents limit “domain name” to web site names. However,
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`no such limitation is found in the claims, and Microsoft merely references its arguments on
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`construing “web site” without showing how “domain name” is necessarily linked to web site names.
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`Accordingly, “domain name” is not limited to web site names.
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`Finally, Microsoft contends that “domain name” is limited to a computer name being
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`converted into an IP address. Microsoft supports this proposed limitation by arguing that a “domain
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`name” has the capacity to be converted by DNS into an IP address and that the specification
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`emphasizes this point by describing that identical DNS requests may result in conventional domain
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`name resolution, “host unknown” error messages, or VPN initiation, depending not on whether
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`something is a “domain name” but on what type of web site was requested. However, Microsoft
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`incorrectly argues that a “capacity” to be converted by DNS into an IP address demonstrates a
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`required limitation. A mere capacity to perform an act does not make that act necessary. Thus,
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`Microsoft has not sufficiently supported limiting “domain name” to a computer name being
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`converted into an IP address. Accordingly, the Court construes “domain name” as “a name
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`corresponding to an IP address.”
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`“web site”
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`The ‘135 patent, claims 1 and 10 contain the term “web site.” VirnetX contends that
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`construing “secure web site” as addressed below sufficiently addresses the meaning of “web site”
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`and that “web site” does not require further construction. Alternatively, VirnetX contends that “web
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`site” means “a computer associated with a domain name and that can communicate in a network.”
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`Microsoft contends that “web site” means “one or more related web pages at a location on the World
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`Wide Web.” The parties dispute whether “web site” should be given a construction separate from
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`“secure web site” and whether “web site” is limited to web pages on the World Wide Web.
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`VirnetX argues that “web site” should not be construed separately from “secure web site”
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`because the ‘135 patent claims never state “web site” without the preceding word “secure.”
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`However, “secure” is separable from “web site” as a modifier of “web site.” The claims show that
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`“secure” can be replaced by other modifiers to “web site.” Claims 1 and 10 of the ‘135 patent refer
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`to “web site” preceded by “non-secure” and “secure target.” Col. 47:28, 30; Col. 48:10, 14. This
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`demonstrates that “web site” can be separated from its modifier and thus is its own term separate
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`from “secure.” Thus, “web site” may be construed as its own claim te