       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                ______________________

             ARISTA NETWORKS, INC.,
                    Appellant

                           v.

               CISCO SYSTEMS, INC.,
                    Cross-Appellant
                ______________________

                 2017-2336, 2017-2347
                ______________________

   Appeals from the United States Patent and Trade-
mark Office, Patent Trial and Appeal Board in No.
IPR2016-00303.
               ______________________

              Decided: November 9, 2018
               ______________________

    MATTHEW D. POWERS, Tensegrity Law Group, LLP,
Redwood Shores, CA, argued for appellant. Also repre-
sented by ROBERT LEWIS GERRITY, WILLIAM P. NELSON;
LAUREN ANN DEGNAN, MICHAEL J. MCKEON, LINHONG
ZHANG, Fish & Richardson, PC, Washington, DC;
ALEKSANDR GELBERG, SETH MCCARTHY SPROUL, San
Diego, CA.

   JOHN C. O’QUINN, Kirkland & Ellis LLP, Washington,
DC, argued for cross-appellant. Also represented by
2               ARISTA NETWORKS, INC.   v. CISCO SYSTEMS, INC.



CRAIG THOMAS MURRAY, CALVIN ALEXANDER SHANK,
JASON M. WILCOX; BENJAMIN A. HERBERT, Los Angeles,
CA; JON WRIGHT, Sterne Kessler Goldstein & Fox, PLLC,
Washington, DC.
                ______________________

      Before PROST, Chief Judge, SCHALL and CHEN,
                     Circuit Judges.
PROST, Chief Judge.
    In this inter partes review, Arista Networks, Inc.
(“Arista”) challenged the validity of claims 1, 2, 7–10, 12–
16, 18–22, 25, and 28–31 of U.S. Patent No. 6,377,577
(“the ’577 patent”). The Patent Trial and Appeal Board
(“Board”) held all but one of the challenged claims invalid.
We affirm.
                             I
    Transmission of data packets between devices in a
computer network may be restricted using access control
techniques. One technique is to use access control lists
(“ACLs”) that include “access control specifiers” describing
which devices are permitted to send packets to which
other devices. ’577 patent col. 1 ll. 9–21.
    The ’577 patent generally relates to methods for per-
forming access control using access control specifiers from
an ACL that are recorded in a content-addressable
memory (“CAM”). Id. at col. 2 ll. 38–44, col. 4 ll. 34–36.
The specification describes an “access control element”
that determines whether to allow transmission of a par-
ticular data packet. Id. at col. 3 ll. 36–38. When a data
packet arrives at the access control element, certain
information from the packet is compared with each access
control specifier in the CAM. Id. at col. 4 ll. 34–47. For
each access control specifier, a “priority encoder” receives
an indicator as to whether that access control specifier
matched the packet’s information. Id. at col. 4 ll. 48–51.
ARISTA NETWORKS, INC.   v. CISCO SYSTEMS, INC.              3



The priority encoder then selects the access control speci-
fier with the highest priority and provides an indicator of
that access control specifier to an output port. Id. at col. 4
ll. 48–55. The indicator provided to the output port
indicates whether the packet may be transmitted from its
source device to its intended destination device. Id. at
col. 4 ll. 57–60.
    Claim 1 of the patent is representative and states:
    1. A method, including the steps of maintaining a
    set of access control patterns in at least one asso-
    ciative memory;
        receiving a packet label responsive to a pack-
        et, said packet label being sufficient to per-
        form access control processing for said packet;
        matching matchable information, said match-
        able information being responsive to said
        packet label, with said set of access control
        patterns in parallel, and generating a set of
        matches in response thereto, each said match
        having priority information associated there-
        with;
        selecting at least one of said matches in re-
        sponse to said priority information, and gen-
        erating an access result in response to said at
        least one selected match; and
        making a [r]outing-decision in response to
        said access result.
Id. at claim 1. Meanwhile, claim 2 recites:
    2. A method as in claim 1, including the step of
    performing at least two of said steps of receiving,
    matching, selecting, and making a routing deci-
    sion, in parallel using a pipeline technique.
Id. at claim 2.
4              ARISTA NETWORKS, INC.   v. CISCO SYSTEMS, INC.



    The Board held all challenged claims, except claim 2,
invalid as obvious based on the combination of
U.S. Patent No. 5,467,349 (“Huey”) in view of the ATM
User-Network Interface Specification, Version 3.0, Sept.
10, 1993 (“ATM UNI Specification”). Arista Networks,
Inc. v. Cisco Sys., Inc., IPR2016-00303, 2017 WL 2304429,
at *16 (May 25, 2017) (Paper 53) (“Final Written Deci-
sion”). Arista timely appealed the Board’s decision up-
holding the validity of claim 2. Cisco timely cross-
appealed with respect to the invalidated claims. We have
jurisdiction under 28 U.S.C. § 1295(a)(4)(A).
                            II
    Obviousness is a question of law based on underlying
factual inquiries. In re Applied Materials, Inc., 692 F.3d
1289, 1294 (Fed. Cir. 2012). We review the Board’s obvi-
ousness determination de novo, and we review its factual
findings for substantial evidence. Id.
                            A
    Arista’s appeal seeks to overturn the Board’s decision
upholding the validity of claim 2. Specifically, Arista
contends that the Board’s analysis of the “in parallel
using a pipeline technique” limitation of claim 2 was
flawed.
    Arista first argues that the Board erred by reading
this limitation to require that the relevant steps be per-
formed on the same packet at the same time, rather than
on different packets at the same time. Appellant’s Br. 27–
34. But there was no dispute between the parties on this
issue before the Board. See Final Written Decision, at *14
(“Patent Owner does not appear to suggest that the
relevant steps must occur on the same packet at the same
time.” (emphasis added)). Moreover, there is no indica-
tion that the Board’s analysis required the steps to be
performed on the same packet. To the contrary, immedi-
ately after the statement Arista takes issue with, the
ARISTA NETWORKS, INC.   v. CISCO SYSTEMS, INC.              5



Board concluded that Arista’s argument that steps must
occur at the same time for different packets was “irrele-
vant” given that Cisco did not raise an argument to the
contrary. Id. In short, there is simply no reason to be-
lieve that the Board’s analysis required the steps to be
performed on the same packet at the same time. We
therefore decline to address this issue further. And to the
extent Arista disputes the Board’s factual findings with
respect to whether Huey and the ATM UNI Specification
disclose this limitation under the understanding that
steps are performed on different packets at the same time,
there is substantial evidence to support the Board’s
findings.
     Arista next argues that the Board did not sufficiently
consider two pieces of evidence related to this limitation:
(1) certain deposition testimony of Arista’s expert, Dr.
Chao; and (2) a book titled “The Architecture of Pipelined
Computers” by Peter Kogge (“Kogge”). Appellant’s Br.
35–40. In Arista’s view, this evidence demonstrated that
one of ordinary skill would have understood Huey and the
ATM UNI Specification as satisfying the “in parallel using
a pipeline technique” limitation of claim 2. But Arista
raised both pieces of evidence for the first time in its reply
brief before the Board. Moreover, the Board explained
why Kogge did not support Arista’s position, and there is
substantial evidence to support the Board’s analysis. See
Final Written Decision, at *14–15. We find no error in the
Board’s treatment of this evidence.
                              B
    In its cross-appeal, Cisco challenges the merits of the
Board’s patentability analysis as well as the Board’s
refusal to apply the doctrine of assignor estoppel. Alt-
hough Cisco attempts to frame its patentability argu-
ments as claim construction disputes, the arguments
appear to be directed to the Board’s factual analysis of the
prior art, which we review for substantial evidence.
6               ARISTA NETWORKS, INC.   v. CISCO SYSTEMS, INC.



    First, Cisco contends that the Board erroneously con-
cluded that the claims of the ’577 patent allow for some
steps to be performed via software. Cross-Appellant’s Br.
64–69. Although the parties appear to agree that the
claims incorporate at least one hardware element (the
CAM), and that certain claimed steps necessary to im-
plement access control (namely, the “maintaining” and
“matching” steps) are performed in that hardware ele-
ment, nothing in the claim language limits the remaining
steps to being performed on hardware.
    Cisco’s remaining patentability arguments are also
unpersuasive. There is substantial evidence to support
the Board’s finding that Huey’s virtual channel and
virtual path addresses, which are stored in CAM arrays in
the address handler, satisfy the “access control patterns”
limitation of the claims. Final Written Decision, at *6,
*10–11. Likewise, substantial evidence supports the
Board’s finding that Huey’s cell policer satisfies the claim
limitation requiring an access result to be generated “in
response to” a match. See id. On this point, the Board
found that no cell in Huey is discarded by the cell policer
unless that cell has first been matched by the address
handler. Id. at *11. And, as the Board noted, there is
simply no requirement in the claims that access control
patterns be directly used in making the ultimate routing
decision. Id.
    Finally, as to the overarching issue of assignor estop-
pel, this court held in a concurrently issued opinion that
assignor estoppel does not apply in inter partes review
proceedings. Arista Networks, Inc. v. Cisco Sys., Inc., No.
17-1725, slip. op. at 17–23 (Fed. Cir. Nov. 9, 2018). Cis-
co’s argument regarding assignor estoppel is therefore
unavailing.
ARISTA NETWORKS, INC.   v. CISCO SYSTEMS, INC.        7



                              III
   For the reasons above, we affirm the decision of the
Board with respect to Arista’s appeal and Cisco’s cross-
appeal.
                        AFFIRMED
                            COSTS
   The parties shall bear their own costs.
