       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                ______________________

 MICROSOFT CORPORATION, INTERNATIONAL
    BUSINESS MACHINES CORPORATION,
               Appellants

                           v.

    PARALLEL NETWORKS LICENSING, LLC,
                   Appellee
            ______________________

2016-2515, 2016-2517, 2016-2518, 2016-2519, 2016-2642,
           2016-2644, 2016-2645, 2016-2646
               ______________________

   Appeals from the United States Patent and Trade-
mark Office, Patent Trial and Appeal Board in Nos.
IPR2015-00483,      IPR2015-00484,     IPR2015-00485,
IPR2015-00486,      IPR2015-01729,     IPR2015-01731,
IPR2015-01732, IPR2015-01734.
                ______________________

              Decided: December 1, 2017
               ______________________

    CONSTANTINE L. TRELA, JR., Sidley Austin LLP, Chi-
cago, IL, argued for appellants. Appellant Microsoft
Corporation also represented by RICHARD ALAN
CEDEROTH; MICHAEL D. HATCHER, Dallas, TX; JOSHUA
JOHN FOUGERE, DANIEL HAY, JOSEPH A. MICALLEF, Wash-
ington, DC.
2         MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING




    JOHN M. DESMARAIS, Desmarais LLP, New York, NY,
for appellant International Business Machines Corpora-
tion. Also represented by JON TODD HOHENTHANER,
KEVIN KENT MCNISH, JEFFREY SCOTT SEDDON, II.

   CHRISTOPHER THOR BOVENKAMP, McKool Smith, PC,
Dallas, TX, argued for appellee. Also represented by
DOUGLAS AARON CAWLEY; KEVIN P. HESS, DUSTIN MARK
HOWELL, Austin, TX.
                ______________________

    Before DYK, SCHALL, and TARANTO, Circuit Judges.
TARANTO, Circuit Judge.
    Parallel Networks Licensing, LLC owns U.S. Patents
5,894,554 and 6,415,335 (the Parallel Patents), which
describe and claim systems for managing the handling of
requests for World Wide Web pages having dynamic
(changing) content. ’554 patent, col. 2, lines 15–19, lines
20–32; ’335 patent, col. 2, lines 15–19, lines 20–32. Paral-
lel sued Microsoft Corp. and International Business
Machines (IBM) for infringement. Microsoft and IBM
subsequently filed petitions with the Patent and Trade-
mark Office seeking inter partes reviews of all claims of
the Parallel Patents under 35 U.S.C. §§ 311–319. The
Patent Trial and Appeal Board, acting as the delegate of
the PTO’s Director under 37 C.F.R. § 42.4(a), instituted
reviews of all challenged claims on anticipation and
obviousness grounds, and it consolidated the proceedings
into two, one for each of the Parallel Patents, with Mi-
crosoft and IBM both involved as petitioners. After
conducting the reviews, the Board concluded that the
petitioners failed to demonstrate anticipation or obvious-
ness.
    Microsoft and IBM appeal the Board’s decisions, argu-
ing that the Board erred in construing the claim term
MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING             3



“request” and in rejecting the arguments for unpatentabil-
ity. We affirm the Board’s claim construction, but we
vacate in part the determination regarding anticipation,
vacate the Board’s determination regarding obviousness,
and remand for further proceedings.
                               I
                              A
     The Parallel Patents claim priority to an application
filed in 1996. By the mid-1990s, the number of Web page
requests had grown large. See ’554 patent, col. 1, lines
39–41, col. 4, lines 33–39. 1 If many requests came to a
single-processor server simultaneously, the server could
be overwhelmed, and the efficiency of fulfilling requests
could suffer. Id., col. 4, lines 38–51. The Parallel Patents
address the problem of processing numerous dynamic
Web page generation requests using a partitioned archi-
tecture. Id. at col. 4, lines 51–53. The partitioned archi-
tecture includes a Web server, interceptor, dispatcher,
and multiple page servers. Id., fig. 4. The basic method
recited in the challenged claims is as follows: (1) a Web
page request is sent to a Web server; (2) the request is
intercepted; (3) an appropriate page server to process the
request is determined; and (4) the request is routed to the
appropriate page server. See id., col. 4, lines 54–60, col. 5,
lines 38–43 & fig. 4.
    The page server is determined based on dynamic sys-
tem resource information, e.g., the data sources each page
server can access and the number of requests each page
server is processing. Id., col. 5, line 49 through col. 6, line
19. By routing a request to a page server, the Web server


    1   The ’335 patent issued from a divisional applica-
tion that claims priority to the ’554 patent’s underlying
application; the specifications are nearly identical. Thus,
we omit duplicate citations to the ’335 patent.
4         MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING



is free to “concurrently process other Web client requests.”
Id., col. 6, lines 20–25. The partitioned architecture
allows the page servers and the Web server “to simulta-
neously process different requests, thus increasing the
efficiency of the Web site.” Id., col. 6, lines 24–28.
    In July 2012, the PTO issued ex parte reexamination
certificates for both of the Parallel Patents. 2 All of the
original claims in the ’554 patent were canceled and new
claims 12–49 were added. J.A. 67. Similarly, all of the
original claims in the ’335 patent were canceled and new
claims 30–85 were added. J.A. 88. For present purposes,
claim 12 of the ’554 patent is representative. It reads:
    A computer-implemented method for managing a
     dynamic Web page generation request to a Web
     server, said computer-implemented method
     comprising the steps of:
    routing said request from said Web server to a se-
      lected page server, said selected page server re-
      ceiving said request and releasing said Web
      server to process other requests, wherein said
      routing step further includes the steps of inter-
      cepting said request at said Web server, routing
      said request from said Web server to a dispatch-
      er, and dispatching, by said dispatcher, said re-
      quest to said selected page server;
    processing said request, said processing being per-
      formed by said selected page server while said
      Web server concurrently processes said other
      requests; and


    2   The ’335 patent’s ex parte reexamination certifi-
cate issued on July 17, 2012, and the ’554 patent’s ex
parte reexamination certificate issued on July 24, 2012.
Corresponding certificates of correction issued on those
same days. J.A. 66–74, J.A. 87–97.
MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING            5



   dynamically generating a Web page by said se-
    lected page server in response to said request,
    said Web page including data dynamically re-
    trieved from one or more data sources; and
   wherein dispatching includes:
       examining said request to make a selection of
         which page server should process said request
         from among a plurality of page servers that
         can each generate said Web page requested by
         said request;
       selecting one of said plurality of page servers to
         dynamically generate said Web page;
       wherein said selection is based on examining
        dynamic information regarding a load associ-
        ated with each of said plurality of page serv-
        ers; and
       sending said request to said selected page server
         based on said examination.
J.A. 69 (certificate of correction). The dispatcher may
reside on the same machine as the Web server or on a
different machine. ’554 patent, col. 5, lines 8–28.
                              B
    In December 2014, Microsoft filed four petitions for
inter partes reviews, together challenging all claims of the
Parallel Patents under 35 U.S.C. §§ 102 and 103. 3 As to
the ’554 patent, the Board instituted reviews of claims
12–19, 32, 34, 46 and 48 in IPR2015-00483 (IPR-483) and


   3    The Parallel Patents claim priority to a 1996 ap-
plication and are governed by the versions of §§ 102 and
103 that were in effect before amendment by the Leahy-
Smith America Invents Act, Pub. L. No. 112-29, § 3(n)(1),
125 Stat. 284, 293 (2011).
6         MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING



claims 12, 20–31, 33, 35–45, 47 and 49 in IPR2015-00484.
The Board consolidated those reviews into IPR-483, which
involves claims 12–49 of the ’554 patent. As to the ’335
patent, the Board instituted reviews of claims 30–40, 43–
53, and 56–85 in IPR2015-00485 (IPR-485) and claims 32,
33, 35–42, 45, 46, 48–55, 65, 69, 80, and 84 in IPR2015-
00486. The Board consolidated those reviews in IPR-485,
which involves claims 30–85 of the ’335 patent. In August
2015, IBM filed four petitions for inter partes reviews, all
substantially similar to the Microsoft petitions. The
Board instituted reviews on the IBM petitions and joined
IBM as a petitioner to IPR-483 and IPR-485.
    In its August 2016 Final Written Decision for IPR-
483, the Board concluded that Microsoft and IBM (hereaf-
ter collectively “Microsoft”) failed to demonstrate the
unpatentability of claims 12–49 of the ’554 patent over
the cited prior art. Microsoft Corp. v. Parallel Networks
Licensing, LLC, IPR2015-00483, 2016 WL 8944632, at *11
(P.T.A.B. Aug. 11, 2016) (IPR-483 Final Decision). The
Board reached the same conclusion in IPR-485 for claims
30–85 of the ’335 patent. Microsoft Corp. v. Parallel
Networks Licensing, LLC, IPR2015-00485, 2016 WL
8999702, at *10 (P.T.A.B. Aug. 11, 2016) (IPR-485 Final
Decision). 4
   Microsoft appeals the Board’s Final Written Decisions
under 35 U.S.C. §§ 141(c) and 319. We have jurisdiction
under 28 U.S.C. § 1295(a)(4)(A).
                             II
    The main prior-art reference considered by the Board
for both anticipation and obviousness is a 1995 publica-


    4   The Board’s Final Written Decisions in IPR-483
and IPR-485 are substantially similar. We will refer only
to the decision in IPR-483, but our conclusions apply to
both.
MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING          7



tion by Daniel Andresen and others: SWEB: Towards a
Scalable World Wide Web Server on Multicomputers,
Dept. of Computer Sci. Tech. Report TRCS95-17, U.C.
Santa Barbara (Sept. 1995) (SWEB). The publication
discloses a “scalable Web server” implemented on a “clus-
ter of workstations and parallel machines” for the efficient
processing of relatively large numbers of simultaneous
Web page requests. Id. at 1–2. The system includes a
number of distributed Web servers that can either (a)
themselves act as a page server when appropriate or (b),
based on dynamic system load information, identify
another Web server that can more efficiently get the
client the desired information and take steps to have that
server do so. Id. SWEB states that its preferred process
for the latter is “URL redirection,” which refers to the
Uniform Resource Locator tool for finding Web resources.
Id. at 10. Figure 6 in SWEB, reproduced below, illus-
trates that process. Id. at 11.




     The Web client (C) sends a Website host name, de-
termined from a URL, to a domain name server (DNS),
asking for an Internet Protocol (IP) address for a Web
server (S?) hosting the site. Id. at 5. In the figure, the
initial server to which the DNS directs the client is server
S0. That server, like others in the system, contains a
8          MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING



scheduler (dispatcher) that communicates with all other
Web servers to exchange system load information. Id. at
9. When the client sends request r to server S0, the
scheduler determines whether S0 or some other server
should supply the client the desired information. Id.
     If, at the time, server S1 is preferable to S0 as a
source for the client to get the desired information, “URL
Redirection” is used to bring about a connection between
the client and S1. Id. at 10. “[W]hen client C sends a
request [r] to server S0, S0 returns a rewritten URL r'
and a response code indicating the information is located
at r'. C then follows r' to retrieve the resulting file f.” Id.
The client computer can take the needed steps without a
new action by, or even the knowledge of, the human user
of client C: “Most Net browsers and clients automatically
query the new location, so redirection is virtually trans-
parent to the user.” Id.
    This URL redirection process, while preferred by
SWEB, is not the only process described in SWEB for
changing the server that will actually supply the client-
desired information. Before describing URL redirection,
SWEB states that, where a server other than the initially
contacted one would be better for serving the client at the
time, “[t]he best situation would be to modify the UNIX
sockets package” so that the initially contacted server
sends the request directly to the desired Web server. Id.
at 10. SWEB explains, however, that such modification
“is difficult since it requires a substantial modification of
the UNIX operating system kernel.” Id. It then explains
the advantages of URL redirection and also the disad-
vantages, which it indicates are small. Id. at 10–11.
    The primary advantages of URL redirection, SWEB
states, are simplicity and universal compatibility. Id. at
10. “The primary disadvantage of URL redirection in
practice is the added overhead of an additional con-
nect/pass request/parse/respond cycle after the redirection
MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING           9



occurs.” Id. at 11. SWEB evaluates the magnitude of the
disadvantage. It sets forth a mathematical model based
on “a very short reply going back to the client browser,
who then automatically issues another request to the new
server address.” Id. at 14. It reports experimental results
showing added overhead of URL redirection on the order
of a few milliseconds in an overall process that took
multiple seconds to complete. Id. at 21. SWEB character-
izes this added overhead as “insignificant.” Id. at 23.
                             III
                             A
    Microsoft first argues that the Board, when evaluat-
ing anticipation and obviousness, erroneously modified its
otherwise-proper claim construction. The only claim term
at issue on appeal is “request” in the required “dynamic
Web page generation request.” The Board expressly
adopted the construction of “request” that the parties
agreed on during the pending district court litigation: “a
message that asks for a Web page.” IPR-483 Final Deci-
sion, 2016 WL 8944632, at *4.
    When conducting its analysis of the alleged anticipa-
tion by SWEB, the Board explained that the claims of the
Parallel Patents “are directed to the routing and pro-
cessing of a single request.” Id. at *5. That conclusion is
not meaningfully in dispute here. And in any event, we
see no error in it.
     What Microsoft argues is that, in its anticipation
analysis of whether SWEB teaches the claim-required
steps involving a single request, the Board changed the
agreed-to simple construction of “request.” Microsoft
contends that the Board imposed requirements on what
can be a “request” based on what Microsoft describes as
(1) the particular route the request travels; (2) the partic-
ular URL or destination specified; and (3) who or what
the request contacts along its route. But the Board did
10        MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING



none of those things. Instead, it determined that, under
the agreed-on construction, each time the client computer
sends a message asking for a Web page, it has made a
new request. IPR-483 Final Decision, 2016 WL 8944632,
at *6. The Board stated “that it is the act of asking—an
action taken by the client computer—that defines a
request.” Id. (emphasis omitted). Contrary to Microsoft’s
contention, that conclusion does not turn on the route
taken, destination, or intermediate contacts.
     Microsoft’s core complaint seems to be that the Board
should have focused on what the client is asking for, not
each individual act of asking, and with that focus should
have treated even multiple acts of asking as a single
“request” as long as the content is the same. We have two
difficulties with this position.
    First, at best (for Microsoft’s purposes), there is ambi-
guity in the agreed-on construction’s term “message”—
whether it refers to substantive communicative content or
to a discrete act of utterance to convey communicative
content. But if there is such ambiguity even in the pre-
sent computer context, it is apparent on the face of the
term. Yet Microsoft agreed to the term “message” as the
defining construction in district court, leaving it to the
fact finder to apply it. And in the present proceedings,
Microsoft never presented to the Board a request for
further claim construction.
    Second, we agree with the Board as to the best con-
struction in the context of this patent. This patent con-
cerns computers sending out communications that other
machines must process, with both the sending and the
processing requiring expenditure of precious time and
scarce resources. In this context, the more natural under-
standing of “request,” as of “message,” is one denoting
each discrete act of communicating, not one that equates
MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING        11



discrete utterances when they convey the same content.
IPR-483 Final Decision, 2016 WL 8944632, at *6–8. 5
   Accordingly, we reject Microsoft’s assertion that the
Board committed a claim-construction error.
                             B
    “[T]he dispositive question regarding anticipation is
whether one skilled in the art would reasonably under-
stand or infer from the prior art reference’s teaching that
every claim element was disclosed in that single refer-
ence.” Dayco Prods., Inc. v. Total Containment, Inc., 329
F.3d 1358, 1368 (Fed. Cir. 2003) (internal quotation
marks, alterations, and citation omitted). Anticipation is
a question of fact, subject to review for substantial evi-
dence. In re Rambus, 753 F.3d 1253, 1256 (Fed. Cir.
2014).
    Microsoft challenged the Parallel Patents as antici-
pated by two separate methods disclosed in SWEB: (1)
URL redirection; and (2) modifying the UNIX sockets
package. We affirm the Board’s finding that SWEB’s
URL redirection method does not anticipate the claims of
the Parallel Patents. But the Board failed to address the
allegation of anticipation by the UNIX sockets modifica-
tion method. We therefore vacate the Board’s rejection of
anticipation in part and remand for the Board to consider
that ground of anticipation in the first instance.


   5    Because the Parallel Patents expired on April 23,
2016, before the Board issued its Final Written Decisions,
the Board properly applied judicial claim-construction
principles to identify the best construction, rather than
seeking to identify the broadest reasonable construction.
See In re Rambus Inc., 694 F.3d 42, 46 (Fed. Cir. 2012)
(inter partes reexamination); Black & Decker, Inc. v.
Positec USA, Inc., 646 F. App’x 1019, 1024 (Fed. Cir.
2016) (inter partes review).
12        MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING



                              1
    Substantial evidence supports the Board’s finding
that the Web client in the URL redirection disclosure in
SWEB makes two separate requests as that term is used
in the Parallel Patents. One is made when the initial
request (r) is sent to the Web server selected by the DNS
server. Another is made when the request (r') is sent to
the second Web server identified by the scheduler. IPR-
483 Final Decision, 2016 WL 8944632, at *8.
    Putting aside Microsoft’s claim-construction argu-
ment, which we have already rejected, Microsoft makes
only one response. It accepts the Board’s focus on the
redirection from one server to another. But it points out
that the client computer’s human user makes only one
communication—gives the client computer an instruction
only once—in the SWEB URL redirection method in that
circumstance. Microsoft’s Opening Br. 44–45; Microsoft’s
Reply Br. 13. But that is irrelevant under the Parallel
Patents. The patents refer interchangeably (for these
purposes) to a request, Web client request, Web browser
request, and URL request. And, more generally, the
patents make clear that the requesting entity is the user’s
computer, i.e., the Web client, not the client’s human user.
’554 patent, col. 4, line 55 (“Web client 200 issues a URL
request”), col. 6, lines 29–30 (“Web page is . . . transmitted
back to requesting Web client 200”).
    We find no error in the Board’s determination that
SWEB’s URL redirection method fails to anticipate the
challenged claims of the Parallel Patents.
                              2
     Microsoft challenges the Board’s rejection of anticipa-
tion by SWEB on a separate ground. It observes, correct-
ly, that the Board failed to address Microsoft’s argument
for anticipation based on SWEB’s disclosure—as an
alternative to URL redirection—of modifying the UNIX
MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING          13



sockets package of a server that has received a request so
that the server forwards the request to a second server
without, as in URL redirection, involving the client in
initiating contact with the second server. Such a process
is a form of what Microsoft’s expert (and the Board) called
“request forwarding” as a name for what the Parallel
Patents require. See IPR-483 Final Decision, 2016 WL
8944632, at *9 (quoting J.A. 11449). We agree with
Microsoft that the Board erred in not addressing this
argument.
    Parallel could not show that the Board actually did
address this separate basis of alleged anticipation. It
argues, however, that Microsoft waived this ground of
anticipation. We cannot so find. Microsoft stated in its
petitions that SWEB discloses two methods for routing
requests: URL redirection and UNIX socket modification.
J.A. 228. Microsoft also clearly argued UNIX socket
modification as an alternative ground for anticipation of
the Parallel Patents’ routing limitation. J.A. 231. The
Board did not find that those clear statements were
insufficient to entitle Microsoft to a decision on the issue,
and Parallel has not identified a regulatory or comparable
requirement for preservation that Microsoft failed to
meet. We see no basis for Parallel’s argument for finding
a complete waiver of the issue.
    We vacate the rejection of anticipation in part and
remand for the Board to consider the issue of anticipation
by SWEB’s disclosure of modifying the UNIX sockets
package. The Board may consider whether Microsoft
committed a waiver and, if so, the scope of the waiver. If
the Board finds no waiver, it should consider whether
Microsoft has met the required elements of anticipation—
“disclosure of all elements of [the] claimed invention
arranged as in the claim.” Connell v. Sears, Roebuck &
Co., 722 F.2d 1542, 1548 (Fed. Cir. 1983). And, if neces-
sary, the Board should address Parallel’s contention that
this disclosure in SWEB is not enabled—applying our law
14        MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING



that generally accords a presumption of enablement to
printed-publication and patent prior art. In re Antor
Media Corp., 689 F.3d 1282, 1289, 1292 (Fed. Cir. 2012)
(printed publications); Amgen Inc. v. Hoechst Marion
Roussel, Inc., 314 F.3d 1313, 1355 (Fed. Cir. 2003) (pa-
tents).
                             C
    Microsoft challenged the claims of the Parallel Pa-
tents as unpatentable for obviousness over SWEB (and
other prior art) even if SWEB did not anticipate the
“request forwarding” required by the claims. In rejecting
the obviousness challenge, the Board relied on its deter-
mination that Microsoft and its expert had “not articulat-
ed a sufficient reason why a person of ordinary skill in the
art would have modified SWEB to include request for-
warding.” IPR-483 Final Decision, 2016 WL 8944632, at
*9–10. Microsoft argues on appeal that the Board failed
to give proper effect to the testimony of its expert under
the legal standards for obviousness. We agree to this
extent: the Board provided insufficient explanation to
justify rejecting the challenge. We vacate the rejection of
the obviousness challenge and remand for further pro-
ceedings on that challenge. See, e.g., In re Nuvasive, Inc.,
842 F.3d 1376, 1383 (Fed. Cir. 2016); Synopsys, Inc. v.
Mentor Graphics Corp., 814 F.3d 1309, 1322 (Fed. Cir.
2016), overruled on other grounds by Aqua Prod., Inc. v.
Matal, 872 F.3d 1290 (Fed. Cir. 2017); In re Sang Su Lee,
277 F.3d 1338, 1346 (Fed. Cir. 2002).
    An obviousness challenger “must demonstrate . . .
that a skilled artisan would have had reason to combine
[or modify] the teaching of the prior art references to
achieve the claimed invention, and that the skilled arti-
san would have had a reasonable expectation of success
from doing so.” Redline Detection, LLC v. Star Enviro-
tech, Inc., 811 F.3d 435, 449 (Fed. Cir. 2015) (quoting PAR
Pharm., Inc. v. TWI Pharm., Inc., 773 F.3d 1186, 1193
MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING         15



(Fed. Cir. 2014)). A reason “to modify a reference can
come from the knowledge of those skilled in the art, from
the prior art reference itself, or from the nature of the
problem to be solved.” SIBIA Neurosciences, Inc. v. Cadus
Pharm. Corp., 225 F.3d 1349, 1356 (Fed. Cir. 2000).
     Those standards can and must be understood to follow
the Supreme Court’s various formulations in KSR Int’l
Co. v. Teleflex, Inc., 550 U.S. 398 (2007). The KSR formu-
lations include those referring to the “combination of
familiar elements according to known methods” that “does
no more than yield predictable results,” id. at 416; “a
structure already known in the prior art that is altered by
the mere substitution of one element for another known in
the field,” requiring more than “a predictable result” for
patentability, id.; “‘simply arrang[ing] old elements with
each performing the same function it had been known to
perform,’ and yield[ing] no more than one would expect
from such an arrangement,” id. at 417; “a technique [that]
has been used to improve one device,” where “a person of
ordinary skill in the art would recognize that it would
improve similar devices in the same way” and that appli-
cation is not beyond the ordinary skilled artisan’s skill,
id.; “the simple substitution of one known element for
another or the mere application of a known technique to a
piece of prior art ready for the improvement,” id.; circum-
stances in which “there is a design need or market pres-
sure to solve a problem and there are a finite number of
identified, predictable solutions” and “the known options
[are] within [an ordinary skilled artisan’s] technical
grasp” and pursuing those options “leads to the anticipat-
ed success,” in which case the options are “obvious to try”
and “might” be obvious, id. at 421. That enumeration is
not exhaustive, and we are not identifying what aspects of
KSR are ultimately important in this case.
     Microsoft’s expert, Dr. Mitzenmacher, stated in his in-
itial declaration:
16         MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING



          214. To the extent Patent Owner may argue
     that SWEB 95 does not disclose “routing said re-
     quest from said Web server to a selected page serv-
     er” considering either disclosed method of sending
     requests to other servers, it would have been obvi-
     ous to include that functionality in the scheme of
     SWEB 95. It was known in the prior art to route
     requests from one machine to another via request
     forwarding based upon a determination of which
     server should be used to process such a request.
     See, e.g., Berson, Client/Server Architecture (2d.
     ed. 1996) (published by April 11, 1996 per U.S.
     Copyright Office) (“Berson”) (Ex. 1036) at 207-208
     [J.A. 13311–12] (“Client/server interactions are
     defined as those in which a client initiates the in-
     teraction and requests a particular service from
     its ‘home’ server. This server reacts to the client’s
     request by either performing the desired service
     or routing the request to another server for ful-
     fillment of the request; irrespective of the final lo-
     cation of the service, the original or home server
     sends the response back to the client.”); Pfister, In
     Search of Clusters (1995) (“Pfister”) (Ex. 1037) at
     78 (processing node in a cluster may “dynamically
     move work from one internal node to another to
     better balance the node”), 226-228 [J.A. 13926–
     28]; Ex. 1012 [Garland et al., Implementing Dis-
     tributed Server Groups for the World Wide Web
     (1995)] at 8 [J.A. 12427] (“We could also extend
     the dispatcher to support anonymous members. It
     is conceivable that some servers might not want to
     advertise their location to the rest of the world. In
     this case, the dispatcher could serve as an inter-
     mediary between the client and the anonymous
     server.”) (emphasis added). And performing such
     routing was known to free up CPU cycles and
     memory resources of the sending device – that is
MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING           17



   why the requests are routed away. See, e.g., Ex.
   1036 [Berson] at 9; Ex. 1037 [Pfister] at 226-228
   [J.A. 13926–28]; Ex. 1012 [Garland] at 1 [J.A.
   12420] (“When the volume of requests to a server
   becomes prohibitively high the server tends to
   drop requests and eventually crashes. The service
   provider needs more computing power to meet the
   demands of the clients requesting the service. … A
   fairly obvious solution to this problem is to imple-
   ment a distributed Web server which will spread
   incoming request load among several machines.”)
   (emphasis added). A person of ordinary skill in the
   art would therefore have been motivated to em-
   ploy such a technique in the scheme of SWEB 95,
   which is expressly concerned with the efficient use
   of server resources. See Ex. 1009 [SWEB] at 2
   (“Several resource constraints affect the perfor-
   mance of the server: the CPU speed and memory
   size of one processing unit, the existing system
   load, the transmission bandwidth between the
   processing unit and its local disk, the network la-
   tency and bandwidth between a processing unit
   and a remote disk when the accessed files are not
   stored in the local disk, and disk contention when
   multiple I/O requests access the same disk, can all
   affect the performance. Server scalability is
   achieved by actively monitoring the run time
   CPU, disk IO, and network loads of system re-
   source units, and dynamically scheduling user
   HTTP requests to a proper node for efficient pro-
   cessing.”). Moreover, to do so would have been
   within the level of ordinary skill in the art, as the
   prior art shows, and merely the application of a
   prior art technique for its known purpose to
   achieve a predictable result.
J.A. 11449–51.
18         MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING



    The Board, referring to this testimony, concluded that
Microsoft had not explained why a person of ordinary skill
in the art would have been motivated to modify SWEB’s
URL redirection, because, it determined, the stated
benefits of request forwarding were already provided by
URL redirection. IPR-483 Final Decision, 2016 WL
8944632, at *9. This reasoning is inadequate. It does not
address the legal significance, in light of some of the KSR
formulations, of Dr. Mitzenmacher’s statement, which is
amply supported by references of record, that request
forwarding was a well-known technique for a request-
receiving server to use to get another server to provide the
client the desired information. It does not address the
statement that an interest in anonymity is a reason for
request forwarding. It does not address the statements in
SWEB itself suggesting that the “best situation” might be
to use a form of request forwarding (by UNIX socket
modification) and identifying a “disadvantage” of URL
redirection. SWEB at 10, 11.
     In these circumstances, we conclude that the Board
failed to provide adequate reasoning to support its deter-
mination on the component of the obviousness analysis it
said was decisive. That inadequacy, together with the
failure to consider the contention that SWEB teaches
UNIX sockets modification, requires vacatur of all of the
Board’s obviousness rulings. We remand for reconsidera-
tion of obviousness.
                              IV
    For the foregoing reasons, we affirm the Board’s claim
construction and rejection of anticipation by the URL
redirection embodiment of SWEB. We vacate the rejec-
tion of anticipation based on the UNIX socket modifica-
tion teaching in SWEB and the rejection of the
obviousness challenge. We remand for further proceed-
ings consistent with this opinion.
     No costs.
MICROSOFT CORP.   v. PARALLEL NETWORKS LICENSING   19



  AFFIRMED IN PART, VACATED IN PART, AND
                REMANDED
