`
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`UNITED STATES PATENT AND TRADEMARK OFFICE
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`––––––––––––––––––
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
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`––––––––––––––––––
`
`RIOT GAMES, INC., and
`VALVE CORP.,
`Petitioners,
`
`v.
`
`PALTALK HOLDINGS, INC.,
`Patent Owner.
`
`––––––––––––––––––
`
`Case No. IPR2018-001321
`U.S. Patent No. 6,226,686 & 6,226,686 C1
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`––––––––––––––––––
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`PETITIONERS’ REPLY
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`1 Case IPR2018-01243 has been joined with this proceeding.
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`
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`TABLE OF CONTENTS
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`I.
`
`II.
`
`Introduction .................................................................................................... 1
`
`The Challenged Claims are Unpatentable .................................................. 2
`
`A.
`
`The Combination of Aldred and RFC 1692 was Obvious .................... 2
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`i.
`
`ii.
`
`RFC 1692 Does Not Reorder TCP Segments ............................. 3
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`Aldred Maintains the Order of Serialized Updates ..................... 5
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`iii. Aldred Does Not Require the Use of Large Packets .................. 7
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`iv.
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`The Techniques of Aldred and RFC 1692 are Complementary . 8
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`B.
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`Aldred and RFC 1692 Disclose the Claimed “Aggregated Message,”
`“Server Message,” and “Aggregated Payload” (All Claims) .............. 12
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`i.
`
`ii.
`
`iii.
`
`iv.
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`There is No Basis for PalTalk’s “Transport Layer” Header
`Requirement .............................................................................. 13
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`The ’686 Patent’s Transport Level Protocol Disclosure Cannot
`Support a “Transport Layer” Requirement ............................... 18
`
`PalTalk’s Construction Would Read Out a Preferred
`Embodiment .............................................................................. 20
`
`The ’686 Patent Does Not Disclaim Including “Transport
`Layer” Headers ......................................................................... 21
`
`Claims 22, 41, and 58 are Unpatentable ............................................. 23
`
`Claims 23, 42, and 59 are Unpatentable ............................................. 25
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`Claims 24, 25, 43, 44, 60, and 61 are Unpatentable ........................... 27
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`Remaining Claims ............................................................................... 27
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`C.
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`D.
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`E.
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`F.
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`III. Conclusion .................................................................................................... 28
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`Exhibit List ............................................................................................................. 29
`i
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`Certificate Of Compliance .................................................................................... 32
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`Certificate Of Service............................................................................................. 33
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`
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`ii
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`TABLE OF AUTHORITIES
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` Page(s)
`
`Cases
`Accent Packaging, Inc. v. Leggett & Platt, Inc.,
`707 F.3d 1318 (Fed. Cir. 2013) .......................................................................... 21
`Apple Inc. v. VirnetX Inc.,
`IPR2014-00237, Paper 41 (PTAB May 11, 2015) ............................................... 8
`Bristol-Myers Squibb Co. v. Teva Pharms. USA, Inc.,
`752 F.3d 967 (Fed. Cir. 2014) ............................................................................ 10
`Dealertrack, Inc. v. Huber,
`674 F.3d 1315 (Fed. Cir. 2012) .......................................................................... 21
`In re Fulton,
`391 F.3d 1195 (Fed. Cir. 2004) ...................................................................... 9, 10
`i4i Ltd. P’ship v. Microsoft Corp.,
`598 F.3d 831 (Fed. Cir. 2010) ............................................................................ 22
`KSR Int’l Co. v. Teleflex Inc.,
`550 U.S. 398 (2007) ........................................................................................ 9, 11
`In re Kubin,
`561 F.3d 1351 (Fed. Cir. 2009) .......................................................................... 11
`Liebel-Flarsheim Co. v. Medrad, Inc.,
`358 F. 3d 898 (Fed. Cir. 2004) ........................................................................... 16
`In re Mouttet,
`686 F.3d 1322 (Fed. Cir. 2012) .......................................................................... 24
`PalTalk Holdings, Inc. v. Microsoft Corp.,
`C.A. 2:06-cv-367-DF, Dkt. 55 ............................................................................ 17
`PalTalk Holdings, Inc. v. Riot Games, Inc.,
`C.A. 1:16-cv-1240-JFB-SRF, Dkt. 59, 64, 67, 69 .............................................. 12
`PalTalk Holdings, Inc. v. Sony Comput. Ent. Inc.,
`C.A. 2:09-cv-274-DF, Dkt. 209 (E.D. Tex. Oct. 25, 2010) ................................ 17
`iii
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`Phillips v. AWH Corp.,
`415 F.3d 1303 (Fed. Cir. 2005) .................................................................... 13, 16
`Thorner v. Sony Comput. Entm’t Am. LLC,
`669 F.3d 1362 (Fed. Cir. 2012) .......................................................................... 21
`Vivid Techs., Inc. v. Am. Sci. & Eng’g, Inc.,
`200 F.3d 795 (Fed. Cir. 1999) ............................................................................ 12
`
`iv
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`I.
`
`Introduction
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`PalTalk does not dispute that the combination of Aldred and RFC 1692
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`satisfies the literal language of almost every claim. Instead, PalTalk misreads the
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`references and the Petition’s grounds to manufacture disputes, asserting self-
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`serving limitations contrary to the patents’ disclosures and decades of
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`representations in litigation. Because PalTalk’s Response (Paper 22, “Resp.”) fails
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`to overcome the arguments and substantial evidence in the Petition (Paper 1,
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`“Pet.”) demonstrating the unpatentability of claims 1, 3, 7, 12, 18, 22-27, 36, 41-
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`46, 55, and 58-63 of the ’686 patent, the Board should cancel the challenged
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`claims.
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`PalTalk advances two main arguments with respect to the challenged
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`independent claims. First, PalTalk asserts that RFC 1692’s TMux protocol “could
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`disrupt the required order of the serialisation operation” in Aldred. Resp. 18-28.
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`But RFC 1692, Aldred, and the TCP protocol (which Aldred discloses using) all
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`maintain the order of packets. Patent Owner’s other obviousness arguments
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`likewise ignore the prior art’s express teachings and impermissibly treat a skilled
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`artisan as an automaton. Resp. 29-32.
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`Second, PalTalk advances constructions of “aggregated payload” and
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`“aggregated message”/“server message” that ignore the plain language of the
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`claims, the specification, and the testimony of its own expert. Resp. 4-15, 33-50.
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`1
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`The claims require “aggregating said payload[s],” and the record shows that
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`message headers, including transport headers, may be included in such
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`“payload[s].” There is no basis to limit “aggregati[on]” to scenarios where
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`specific “headers” are removed from messages. And in any event, the prior art
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`identified by Petitioners removes those very headers.
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`PalTalk’s arguments with respect to the dependent claims fare no better and
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`are based on a misreading of the Petition and prior art. For the reasons explained
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`in the Petition and below, every challenged claim should be cancelled.
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`II. The Challenged Claims are Unpatentable
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`A. The Combination of Aldred and RFC 1692 was Obvious
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`An Ordinary Artisan would have found it obvious to extend Aldred’s use of
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`TCP/IP for inter-node data transfer to use RFC 1692’s TMux functionality. Pet.
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`33-38. PalTalk argues against the viability of this combination based on a number
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`of assumptions: (i) that RFC 1692 reorders large and small TCP segments; (ii) that
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`“reordering” TCP segments would interrupt Aldred’s serialization; (iii) that Aldred
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`necessarily requires the use of large packets; and (iv) that an Ordinary Artisan
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`would ignore RFC 1692’s benefits in favor Aldred’s “alternative bandwidth
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`solutions.” Resp. 18-31. As explained below, none of these assumptions are
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`supported by the record.
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`2
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`i.
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`RFC 1692 Does Not Reorder TCP Segments
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`PalTalk argues that, in RFC 1692, “large” TCP segments could be
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`transmitted “out of order” with respect to a pending multiplexed packet (containing
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`“small” TCP segments), thereby violating Aldred’s “order” requirement. Resp. 18-
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`28. But, as explained below, RFC 1692 expressly discloses that large TCP
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`segments can be added to the end of any pending multiplexed packet, such that all
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`segments would be sent in the order received.
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`PalTalk asserts that “large” segments (such as those sent using FTP) in RFC
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`1692 “would be transmitted immediately in a separate IP datagram before the
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`TMuxed message under construction” is sent. Resp. 25-26; Ex.2002, ¶¶68-75.
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`However RFC 1692 merely suggests sending large segments separately. Ex.1010,
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`7. If following that suggestion would have imperiled the functionality of the
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`combination of Aldred and RFC 1692, an Ordinary Artisan would have known to
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`disregard that suggestion in a combined implementation. Ex.1053, ¶¶19-23, 35.
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`In fact, the very next page of RFC 1692 describes such a scenario. In
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`Section 5.2, RFC 1692 explains that when a segment that would not normally be
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`multiplexed—such as a large segment—is received and a multiplexed message is
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`under construction, “the extra segment can be added to the TMux message under
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`construction, and this complete message should be sent immediately ….”
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`Ex.1010, 8-9 (emphasis added). This disclosure specifically relates this
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`3
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`functionality to the “large” segments identified by PalTalk (“segments sent by
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`FTP,” id.), and works analogously to TMux’s operation when sufficient data to fill
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`a multiplexed message is received: “If, during construction of the Multiplexed
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`Message, the buffer holding the message fills, the Multiplexed Message is
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`transmitted immediately.” Ex.1010, 6; Ex.1053, ¶¶19-23. RFC 1692 therefore
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`teaches exactly what PalTalk claims it does not: large and small TCP segments can
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`be sent in-order by the multiplexing process. Ex.1053, ¶¶19-23. Neither PalTalk
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`nor its expert acknowledge, let alone address, this disclosure.
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`Dr. Almeroth further ignores the express disclosures of RFC 1692 in arguing
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`that this reference “does not discuss the order of packets to be TMuxed as being a
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`concern.” Ex.2002, ¶68. But RFC 1692 discusses adding segments to a
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`multiplexed message in the order they are received (Ex.1010, 6-7)2 and also
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`recommends “that the segments in the TMux message should be processed in the
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`same order that they are in the TMux message” (id., 3 (emphasis added)). Having
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`repeatedly ignored its disclosures, Dr. Almeroth’s characterizations of RFC 1692
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`are not credible. Absent PalTalk’s assumption that RFC 1692 reorders large and
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`small TCP segments, PalTalk cannot show that concerns about in-order packet
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`delivery would deter the Ordinary Artisan from combining RFC 1692 with Aldred.
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`
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`2 Patent Owner does not contest that the “small” segments are sent in order.
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`4
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`ii.
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`Aldred Maintains the Order of Serialized Updates
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`Even if PalTalk’s first assumption was correct—that RFC 1692 might re-
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`order some “large” TCP segments relative to “small” TCP segments—PalTalk’s
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`arguments remain premised on another incorrect assumption: that out-of-order
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`TCP segments would go uncorrected by the combined system. Resp. 18-28. But
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`Aldred’s scheme maintains the order of serialized updates regardless of the order
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`of IP packets transmitted by RFC 1692 through both Aldred’s channel mechanism
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`and the use of TCP, as explained below.
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`Aldred’s channel mechanism maintains the order of updates within a
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`channel regardless of the underlying layers. Ex.1053, ¶25. Channels are designed
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`so that a node “receives data packets from the channel in the order in which they
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`were sent,” regardless of the “physical communication network in existence
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`between the nodes.” Ex.1009, 6, 29-30. Aldred’s channels therefore maintain the
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`order of data packets within a given channel. Ex.1009, 6, 51. As Dr. White
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`explains, “Aldred provides an order guarantee at the logical channel level,
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`regardless of the underlying networking scheme.” Ex.1053, ¶25. PalTalk argues
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`that transmitting TCP segments out-of-order would break this functionality, but
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`fails to address Aldred’s disclosure that order is maintained regardless of the
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`physical network’s implementation. Resp. 21-28; Ex.2002, ¶¶73-79.
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`5
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`Aldred’s use of TCP also maintains the order of serialized updates. Aldred
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`supports TCP/IP, and RFC 1692 is an extension of IP that expressly applies to
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`TCP/IP. Ex.1009, 29-30, Fig.10; Ex.1010, 4-8, 10; Ex.1007, ¶¶143-48. The
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`Petition demonstrated that it would be obvious to extend Aldred’s use of TCP/IP to
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`apply RFC 1692 at the IP layer. Pet. 33-38. TCP is “a connection-oriented, end-
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`to-end reliable protocol” that provides a mechanism for recovering “from data that
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`is … delivered out of order by the internet communication system” in the form of
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`“assigning a sequence number to each octet transmitted.” Ex.1051, 1, 4. These
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`sequence numbers are used “to correctly order segments that may be received out
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`of order.” Id., 4, 24-30 (emphasis added). Aldred’s use of TCP/IP would thus
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`guarantee in-order delivery of TCP segments regardless of any purported
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`reordering by RFC 1692’s TMux-enhanced IP layer. Ex.1053, ¶¶28-31.
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`PalTalk and its expert never address TCP’s order guarantee, despite the ’686
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`patent’s express disclosure that “TCP … ensures reliable, in-order delivery.”
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`Ex.1002, 3:45-56 (citing RFC 793 (Ex.1051)). Dr. Almeroth agreed that TCP re-
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`orders out-of-order segments upon receipt. Ex.1052, 11:4-13, 43:7-44:13.
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`Therefore, Aldred and RFC 1692 maintain the correct ordering of packets at every
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`layer of the combined system: (1) Aldred maintains the order of data packets
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`within a logical channel, (2) TCP maintains the order of TCP segments using
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`6
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`sequence numbers,3 and (3) RFC 1692’s TMux-enhanced IP protocol never
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`reorders small and large TCP segments during the multiplexing process. As
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`combined, TMux would not interfere with Aldred’s “order” requirement.
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`iii.
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`Aldred Does Not Require the Use of Large Packets
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`Even if PalTalk’s second assumption was also correct—out-of-order TCP
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`segments are uncorrected by the combined system—PalTalk further unjustifiably
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`assumes that every embodiment of Aldred would require the use of “large” TCP
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`segments. Resp. 18-28.
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`However, neither the challenged claims nor Aldred require “large” packets;
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`both encompass scenarios where only small packets are generated. Ex.1007, ¶146;
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`Ex.2004, 43:15-25; Ex.1053, ¶¶26-27. As one example, PalTalk fails to address
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`Aldred’s support of a “broad spectrum of collaborative applications” (Ex.1009, 1-
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`2), including a shared drawing board application (id., 7), and a chat program where
`
`
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`3 TCP ensures that packets arrive at Aldred’s “receiving ports” in an identical
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`sequence. Ex.1051, 9-10. Aldred’s “ports” are the “ends of channels” and need
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`not correspond to a specific network implementation (e.g., TCP ports). Id., 7.
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`Even assuming that segments were received “out of order” at the network (TCP)
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`level of a node, TCP’s ordering mechanism would ensure in-order delivery at
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`Aldred’s ports (the channel level). Ex.1053, ¶30.
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`7
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`“each participant sees all the exchanged messages, and in the same sequence” (id.,
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`27-28). These applications “would result in messages significantly smaller than
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`the IP protocol supports, such that RFC 1692’s methodology would improve
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`Aldred’s performance by reducing the number of packets.” Ex.1007, ¶146;
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`Ex.2004, 43:15-25 (“The particular systems that I analyzed have short packets
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`….”).
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`PalTalk’s only rebuttal is to construct a hypothetical system that “could
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`involve interactive notation on a foreground plane,” where “if [an] application
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`attaches an image from its local clipboard onto its drawing plane,” then “[i]n many
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`situations the packet … could be deemed a large packet,” causing “a disruption in
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`the packet order.” Resp. 26-27 (emphasis added). However, prior art references
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`“must be evaluated for what they fairly teach one of ordinary skill in the art.” In re
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`Boe, 355, F.2d 961, 965 (CCPA 1968). PalTalk’s “large” packet scenario does not
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`show nonobviousness when the claims and Aldred’s disclosure encompass systems
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`that use only small packets. Apple Inc. v. VirnetX Inc., IPR2014-00237, Paper 41
`
`at 40 (PTAB May 11, 2015) (teaching away must be “commensurate in scope with
`
`the challenged claims”).
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`iv.
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`The Techniques of Aldred and RFC 1692 are Complementary
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`Finally, PalTalk argues that an Ordinary Artisan would not have turned to
`
`RFC 1692 because Aldred “already discusses alternative bandwidth solutions” and
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`8
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`adding TMux “would introduce additional latency into the system.” Resp. 18-19,
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`29-30. But the techniques proposed by RFC 1692 were complementary to the
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`techniques discussed in Aldred, providing ample reason for an Ordinary Artisan to
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`use them together.
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`Aldred’s disclosure of “alternative bandwidth solutions” does not constitute
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`a “teaching away” because disclosing an alternative, without more, does not
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`criticize, discredit, or otherwise discourage the use of another. See In re
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`Fulton, 391 F.3d 1195, 1200-01 (Fed. Cir. 2004). In fact, Aldred actually
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`encourages multiplexing at lower layers—the very technique to which RFC 1692
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`is directed. Ex.1009, 32.
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`Moreover, each of Aldred’s “bandwidth” techniques—degrading video
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`quality, compressing data, or dynamically re-allocating bandwidth across
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`channels—are complementary with TMux. Ex.1053, ¶33. As Dr. White
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`explained, when there is a high-volume of small packets and high data redundancy,
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`TMux and compression are “both obvious things to do” and “[y]ou can use them
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`both at the same time. They’re not exclusive.” Ex.2004, 54:21-55:20; see Ex.1053,
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`¶33.
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`Furthermore, PalTalk’s latency and quality of service arguments (Resp. 30-
`
`31) ignore that “[a] person of ordinary skill is also a person of ordinary creativity,
`
`not an automaton.” KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 419 (2007). Both
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`9
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`Aldred’s quality of service (QOS) requirements and RFC 1692’s timer are
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`configurable (Ex.1009, 39-41; Ex.1010, 6), and RFC 1692 even suggests setting
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`the user-configurable timer small enough so that the “response time” does not
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`become a “problem.” Ex.1010, 6; Ex.1053, ¶36. An Ordinary Artisan would
`
`know how to configure the combination to avoid the complications PalTalk
`
`identifies, e.g., setting the timer short enough that it does not interfere with
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`Aldred’s QOS requirements. Ex.1053, ¶¶35-36. And, any increased latency from
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`RFC 1692’s timer can also be offset by reduced latency from network congestion:
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`“[T]here’s an engineering tradeoff going on here between tolerating a little bit of
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`latency and using up the network bandwidth. … [I]f you have a whole lot of
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`packets going on the network bandwidth, that can also adversely affect latency.”
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`Ex.2004, 50:23-51:10; In re Fulton, 391 F.3d at 1200-01 (“[Obviousness] does not
`
`require that a particular combination must be the preferred, or the most desirable,
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`combination....”). PalTalk and Dr. Almeroth offer no response to this testimony.
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`Moreover, obviousness requires only a showing “that a skilled artisan would
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`have been motivated to combine the teachings of the prior art references to achieve
`
`the claimed invention, and that the skilled artisan would have had a reasonable
`
`expectation of success from doing so.” Bristol-Myers Squibb Co. v. Teva Pharms.
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`USA, Inc., 752 F.3d 967, 973 (Fed. Cir. 2014). A “reasonable expectation of
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`success” does not require “absolute certainty” that a combination would succeed.
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`10
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`In re Kubin, 561 F.3d 1351, 1360 (Fed. Cir. 2009). Dr. Almeroth’s testimony
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`reveals that he did not consider the level of ordinary skill when opining on this
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`issue; this undermines his testimony. For example, after explaining the various
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`ways that he could tune RFC 1692’s configurable timer, he stated that he was “not
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`sure a person of skill in the art at the time would have had the same appreciation
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`….” Ex.1052, 53:11-54:23, 56:3-59:8; but see id., 63:5-64:10 (Dr. Almeroth
`
`teaches network configuration to his undergrads), Resp., 3 n.1 (Ordinary Artisan
`
`would know network protocols and network programming). An Ordinary Artisan
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`would have been more than capable of configuring Aldred and RFC 1692 to
`
`maintain QOS requirements. Ex.1053, ¶¶35-36. Dr. Almeroth’s uncertainty
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`regarding what one of skill in the art would have known shows he has not properly
`
`considered obviousness from the perspective of a skilled artisan, making his
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`testimony on this point unreliable and deserving of little to no weight. See KSR,
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`550 U.S. at 420 (“The question is … whether the combination was obvious to a
`
`person with ordinary skill in the art.”).
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`11
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`B. Aldred and RFC 1692 Disclose the Claimed “Aggregated
`Message,” “Server Message,” and “Aggregated Payload” (All
`Claims)
`
`PalTalk advances arguments premised on impermissibly narrow
`
`constructions of “aggregated message”/“server message”4 and “aggregated
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`payload” (related to its “transport layer” header requirements) that the Board
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`already rejected. Resp. 4-15, 33-50.5 The Board should reject those arguments
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`again because they are contrary to the claims’ ordinary meaning.
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`
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`4 PalTalk’s analysis equates claim 18’s “server message” with the “aggregated
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`message” used in the remaining independent claims. Resp. 2-3 (“‘aggregated
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`message’ … referred to a server message in Claim 18 …”).
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`5 The parties dispute other portions of Patent Owner’s proposed constructions of
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`these terms in district court. See PalTalk Holdings, Inc. v. Riot Games, Inc., C.A.
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`1:16-cv-1240-JFB-SRF, Dkt. 59, 64, 67, 69. Here, as Patent Owner’s patentability
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`arguments rely only on its “transport layer” header requirements, Petitioners
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`respectfully request the Board determine only whether, and to what extent, the
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`claims include Patent Owner’s “transport layer” header requirements. See Vivid
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`Techs., Inc. v. Am. Sci. & Eng’g, Inc., 200 F.3d 795, 803 (Fed. Cir. 1999).
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`12
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`IPR2018-00132 (U.S. Pat. No. 6,226,686)
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`Petitioners’ Reply
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`i.
`
`There is No Basis for PalTalk’s “Transport Layer” Header
`Requirement
`
`Claims 1, 3, 7, 12, and 18 of the ’686 patent do not limit the content of
`
`“payloads,” and thus does not limit what “aggregated payload” and “aggregated
`
`message”/“server message” can comprise. PalTalk concedes that “aggregated
`
`payload” and “aggregated message”/“server message” can encompass
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`encapsulated headers generally (Resp. 8-9), yet fails to justify why the claim
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`requires the “aggregated payload” and “aggregated message”/“server message”
`
`exclude all or all but one of a specific type of header.
`
`The ordinary meaning of these terms is readily apparent from the context in
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`which they appear, Phillips v. AWH Corp., 415 F.3d 1303, 1314 (Fed. Cir. 2005),
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`and this context does not require excluding any headers. Claims 1, 3, 7, 12, and 18
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`separately recites “aggregating,” “message,” and “payload,” and PalTalk do not
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`suggest that those terms require construction. Ex.1052, 68:20-25, 70:5-18, 107:5-
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`108:7. There is no dispute that the claimed “aggregated payload” is the result of
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`“aggregating said payload portions of said [host] messages”/“aggregating said
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`payload portion with the payload portion of a second host message” (Ex.1053,
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`¶¶12-14), or that the claimed “aggregated message”/“server message” is the result
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`of forming a message “using said [aggregated payload]” (id., ¶¶12-14). Thus, the
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`terms “message” and “payload” are used by the ’686 patent in their conventional
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`sense. Ex.1053, ¶¶5-6; Ex.1002, 1:28-55, 3:57-4:17. PalTalk’s district court
`13
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`Petitioners’ Reply
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`construction of “aggregating/aggregated” likewise includes no “transport layer”
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`header requirement. Ex.1055, 2-3. The claims provide sufficient guidance on the
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`meaning of “aggregated payload” and “aggregated message”/“server message.”
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`They do not support excluding any “transport layer” headers.
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`The specification supports this reading of the claims as well. The ’686
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`patent explains the Internet Protocol (IP) and conventional networking use the OSI
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`reference model, where network protocols are layered. Ex.1002, 3:28-56 (citing
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`RFC 791). OSI network layers are hierarchical—the packet for each layer
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`(containing a header and payload) encapsulates the packets for the layers above:
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`thus, an IP packet payload may contain an entire TCP packet including a TCP
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`header and payload. This is shown below in two figures annotated by Dr.
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`Almeroth in testimony from different proceedings. E.g., Ex.1011 (RFC 791), 1
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`(“[The IP module could] take a TCP segment (including the TCP header and user
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`data) as the data portion of an [IP datagram].”).
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`14
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`Petitioners’ Reply
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`Ex.1056, 5.
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`Ex.1058, 3. The “payload portion” of an IP packet could thus comprise a TCP
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`header, and an “aggregated payload” and “aggregated message”/“server message”
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`could have multiple TCP headers. Ex.1053, ¶¶7-8.
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`15
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`Petitioners’ Reply
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`Moreover, PalTalk bases its “transport layer” header limitation on nothing
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`more than an embodiment in the ’686 patent (Ex.1002, 20:21-25), where the server
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`removes Transport Level Protocol (TLP) headers from received messages. Resp.
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`4-11, 13-14. But even if a patent discloses only a single embodiment, the claims
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`of the patent are not “construed as being limited to that embodiment.” Phillips,
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`415 F.3d at 1323 (citation omitted). The focus is instead “on understanding how a
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`person of ordinary skill in the art would understand the claim terms” in light of the
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`specification. Id. at 1323. Notably, Patent Owner points to no “special definition”
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`or lexicography that would redefine “aggregated payload” and “aggregated
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`message”/“server message” from their ordinary meaning as described above. Id. at
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`1316.
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`The doctrine of claim differentiation also undercuts PalTalk’s position. See
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`Liebel-Flarsheim Co. v. Medrad, Inc., 358 F. 3d 898, 910 (Fed. Cir. 2004). Claims
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`1, 3, 7, 12, and 18 do not expressly recite “aggregating” at any specific “layer,”
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`but certain dependent claims recite specific “layers” with respect to their
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`requirements. E.g., claim 14 (“session layer protocol”); claims 28, 29, 48, 47, 64,
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`65 (“upper-level protocol … transport layer protocol”). These dependent claims
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`show PalTalk knew how to draft claims requiring operations at specific “layers”
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`when it wanted to, and it failed to do so with respect to the claimed “aggregating.”
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`16
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`Petitioners’ Reply
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`Finally, PalTalk’s position is further undercut by the broader constructions it
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`proposed, over more than a decade, in district courts and during reexamination—
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`PalTalk never advanced a “transport layer message header” requirement until after
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`these proceedings were filed. E.g., PalTalk Holdings, Inc. v. Sony Comput. Ent.
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`Inc., C.A. 2:09-cv-274-DF, Dkt. 209, at 17 (E.D. Tex. Oct. 25, 2010); PalTalk
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`Holdings, Inc. v. Microsoft Corp., C.A. 2:06-cv-367-DF, Dkt. 55, Ex. A at 7 (E.D.
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`Tex. May 14, 2007); Ex.1005, 396-97; Ex.1006, 234-36; Ex.1052, 108:8-24. In
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`fact, PalTalk proposed constructions of these terms without any limitation as to
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`“headers” as late as January 30, 2018, only two and a half weeks before it filed its
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`preliminary response on February 15, 2018. Ex.1054, Ex. A at 1, 3. Shortly after
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`filing its preliminary responses, it changed its district court positions to follow suit.
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`Ex.1055, 2-4. PalTalk offers no explanation for its reversal.
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`The Board should reject PalTalk’s self-serving “transport layer” header
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`limitations. PalTalk does not contest that Aldred as combined with RFC 1692
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`would disclose an “aggregated message” and an “aggregated payload” without the
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`“transport layer” header requirement. Resp. 42-47. Thus, without these
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`requirements, PalTalk concedes that the combination of Aldred and RFC 1692
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`satisfies each and every element of claims 1, 3, 7, 12, and 18. Id.
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`17
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`Petitioners’ Reply
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`ii.
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`The ’686 Patent’s Transport Level Protocol Disclosure Cannot
`Support a “Transport Layer” Requirement
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`Even assuming arguendo that the claims require removing headers, only
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`Transport Level Protocol (TLP) headers would need to be removed, not “transport
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`layer” headers. Ex.1002, 20:22-23 (“GMS … removes the TLP header from the
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`datagram … .”). This distinction is critical, because RFC 1692 removes, as part of
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`its multiplexing process, the headers that the patent characterizes as TLP headers.
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`The ’686 patent explains that TLP and transport layer protocol are not
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`synonymous. PalTalk attempts to equate these terms, but Transport Level Protocol
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`(TLP) is a coined term that does not directly correspond to “transport layer.”
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`Ex.1002, 8:38-43, 12:46-50; Ex.1052, 79:21-80:15 (Dr. Almeroth: “the patent can
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`characterize a TLP in any way it wants”).
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`Only two embodiments in the patent discuss TLP; in neither is TLP a
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`transport layer protocol. In the first embodiment, the specification explains that
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`the TLP is IP: “As before, a TLP such as IP (where the message header contain[s]
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`the source and destination TLP addresses) is assumed to be used here.” Ex.1002,
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`9:10-12 (emphasis added); Ex.1052, 79:21-80:15 (Dr. Almeroth agreeing that IP is
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`an example of a TLP). Dr. Almeroth testified that IP is not a transport layer
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`protocol. Ex.1052, 79:16-20. In the second embodiment, the specification
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`suggests that the TLP is TCP and IP together: “In the preferred embodiment, the
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`wide area network is the Internet and the TLP protocol is TCP/IP.” Ex.1002,
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`Petitioners’ Reply
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`26:28-29 (emphasis added). Here, the ’686 patent refers to a “TCP/IP header” as a
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`single header. Id., 26:41-43.
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`These disclosures are fatal to PalTalk’s argument because it means every
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`example in the ’686 patent that describes removing a TLP header encompasses
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`removing the IP header alone. Thus, even if the claims are limited to removing a
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`single TLP header, such a negative limitation would not distinguish the prior art.
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`As explained in the Petition and by Dr. White, Aldred in view of RFC 1692 results
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`in an “aggregated payload” without any IP headers and an “aggregated message”
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`with a single IP header. Pet. 34-38; Ex.1007, ¶¶68-76, 143; Ex.1053, ¶34. The
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`’686 patent’s disclosure of IP as the TLP protocol means that RFC 1692 discloses
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`precisely the same functionality: removing incoming IP headers and sending
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`aggregated messages with only a single IP header.
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`In the second embodiment, disclosing a TLP that is the combined TCP
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`header and IP header, Aldred in view of RFC 1692 would similarly result in at
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`most a single combined TCP header and IP header in the multiplexed packet: the
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`single IP header and the first TCP header. Ex.1010, 2-3, 6-8; Ex.1053, ¶34. The
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`remaining TCP headers would not be TLP headers b