Case: 19-1464 Document: 85 Page: 1 Filed: 07/16/2020
NOTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
ALACRITECH, INC.,
Appellant
v.
INTEL CORPORATION, CAVIUM, LLC, DELL INC.,
Appellees
UNITED STATES,
Intervenor
______________________
2019-1464
______________________
Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in Nos. IPR2017-
01393, IPR2017-01714, IPR2018-00374.
______________________
Decided: July 16, 2020
______________________
SANFORD IAN WEISBURST, Quinn Emanuel Urquhart &
Sullivan, LLP, New York, NY, for appellant. Also repre-
sented by JOSEPH M. PAUNOVICH, Los Angeles, CA.
GARLAND STEPHENS, Weil, Gotshal & Manges LLP,
Houston, TX, for appellee Intel Corporation. Also repre-
sented by MELISSA LARUE HOTZE; GREGORY SILBERT, New
Case: 19-1464 Document: 85 Page: 2 Filed: 07/16/2020
2 ALACRITECH, INC. v. INTEL CORP.
York, NY; AMANDA BRANCH, ANNE MARIE CAPPELLA, Red-
wood Shores, CA.
KARINEH KHACHATOURIAN, Rimon, P.C., Palo Alto, CA,
for appellee Cavium, LLC. Also represented by NIKOLAUS
A. WOLOSZCZUK.
KIRK T. BRADLEY, Alston & Bird LLP, Charlotte, NC,
for appellee Dell Inc. Also represented by EMILY CHAMBERS
WELCH, Atlanta, GA; BRADY COX, Dallas, TX.
MELISSA N. PATTERSON, Appellate Staff, Civil Division,
United States Department of Justice, Washington, DC, for
intervenor. Also represented by ETHAN P. DAVIS,
COURTNEY DIXON, SCOTT R. MCINTOSH; THOMAS W.
KRAUSE, FARHEENA YASMEEN RASHEED, Office of the Solic-
itor, United States Patent and Trademark Office, Alexan-
dria, VA.
______________________
Before MOORE, CHEN, and STOLL, Circuit Judges.
CHEN, Circuit Judge.
Alacritech appeals from the final written decisions of
the Patent Trial and Appeal Board (the Board) in the
above-captioned inter partes review (IPR) proceedings
holding claims 1, 6, 9, 12, and 15 of U.S. Patent No.
9,055,104 invalid as obvious. 1 We affirm.
1 Alacritech’s appeal briefing included a challenge to
the appointment of the administrative patent judges on the
Board under the Appointments Clause of the Constitution,
but this challenge has since been withdrawn and waived.
See Dkt. No. 70.
Case: 19-1464 Document: 85 Page: 3 Filed: 07/16/2020
ALACRITECH, INC. v. INTEL CORP. 3
BACKGROUND
The ’104 patent relates to network communications,
and in particular to the use of a network interface device to
offload network processing tasks from the central pro-
cessing unit (CPU) of a host computer. ’104 patent at Ab-
stract. To transmit data to the network, the computer
supplies a command along with the data to the network in-
terface, which in turn processes and transmits that data
according to the Transmission Control Protocol (TCP) be-
fore indicating to the computer that the data has been
transmitted. Id. at col. 3 ll. 37–47. TCP also requires the
recipient of the data to respond with acknowledgments
(ACKs) indicating to the transmitting device—here, the
network interface—which data has been successfully re-
ceived. Id. at col. 2 ll. 10–15. The claimed invention spec-
ifies that the network interface indicates to the
transmitting computer that the data has been transmitted
“prior to receiving” the ACK for all of the transmitted data.
Claim 1 is representative:
1. A method for communication involving a com-
puter, a network, and a network interface device of
the computer, the network interface device being
coupled to the network, the method comprising:
receiving, by the network interface device from the
computer, a command to transmit application data
from the computer to the network;
sending, by the network interface device to the net-
work, data corresponding to the command, includ-
ing prepending a transport layer header to at least
some of the data;
sending, by the network interface device to the com-
puter, a response to the command indicating that
the data has been sent from the network interface
device to the network, prior to receiving, by the net-
work interface device from the network, an
Case: 19-1464 Document: 85 Page: 4 Filed: 07/16/2020
4 ALACRITECH, INC. v. INTEL CORP.
acknowledgement (ACK) that all the data corre-
sponding to the command has been received; and
maintaining, by the network interface device, a
Transport Control Protocol (TCP) connection that
the command, the data and the ACK correspond to.
Id. at claim 1 (emphasis added).
The Board found all of the challenged claims unpatent-
able over U.S. Patent No. 5,937,169 (Connery) in view of
the knowledge of a skilled artisan and, in the alternative,
over Connery in view of PCT Patent Publication No.
WO 00/13091. Relevant to this appeal, the Board found
that Connery discloses the limitation of “sending, by the
network interface device to the computer, a response to the
command indicating that the data has been sent from the
network interface device to the network,” and that Con-
nery’s network interface sends this response “prior to re-
ceiving . . . an acknowledgment (ACK) that all the data
corresponding to the command has been received.” J.A.
19–25; ’104 patent at claim 1.
Alacritech appeals, and we have jurisdiction under
28 U.S.C. § 1295(a)(4)(A).
DISCUSSION
Obviousness “is a question of law based on underlying
findings of fact.” In re Gartside, 203 F.3d 1305, 1316 (Fed.
Cir. 2000) (citation omitted). We review the Board’s find-
ings regarding the scope and content of the prior art for
substantial evidence. Rambus Inc. v. Rea, 731 F.3d 1248,
1251–52 (Fed. Cir. 2013).
The sole dispute in this appeal relates to what Connery
discloses, and specifically, the relative timing between a
particular “interrupt” message sent from Connery’s net-
work interface to the computer’s central processing unit
(CPU) and the receipt of an ACK sent from a computer that
received the transmitted data.
Case: 19-1464 Document: 85 Page: 5 Filed: 07/16/2020
ALACRITECH, INC. v. INTEL CORP. 5
Like the ’104 patent, Connery discloses that network
protocol processing can be offloaded from the CPU to a net-
work interface. Connery at col. 1 ll. 7–11. As Connery ex-
plains, higher layer network protocols such as TCP were
typically “handled by software drivers” and “a protocol
stack executed in the host processor,” i.e., CPU. Id. at col.
1 ll. 20–21, 31–33. To transmit data according to TCP, the
CPU would first package that data into “appropriately
sized segments.” Id. at col. 1 ll. 37–41. Separately, the
CPU would also monitor acknowledgment (ACK) messages
from the recipient to ensure, for reliability purposes, that
“the amount of data sent onto the network” “does not ex-
ceed” the advertised receiving capacity of the recipient. Id.
at col. 1 l. 56–col. 2 l. 13. To reduce the load on the CPU,
Connery explains that segmentation of data for transmis-
sion can be offloaded from the CPU to the network inter-
face. Id. at col. 7 ll. 47–49, 60–64. With the exception of
data segmentation, Connery’s CPU continues to handle the
remaining aspects of the TCP protocol. Id. at col. 5 ll. 51–
53, col. 6 ll. 15–18.
Connery’s network interface accepts a command from
the CPU to transmit a “large datagram” and divides that
datagram into individually transmitted segments accord-
ing to the TCP network protocol. Id. at col. 2 ll. 46–57.
Once the network interface transmits the data segments of
the large datagram, Connery discloses that the network in-
terface can send a single interrupt to the CPU. Id. at col.
7 ll. 60–63. The parties dispute whether this interrupt sent
by the network interface occurs before, or after, the net-
work interface receives an ACK indicating that all of the
transmitted data was successfully received by a destina-
tion computer.
The Board agreed with the petitioner that a skilled ar-
tisan would understand Connery’s single interrupt per
large datagram as indicating that “all generated packets
from the large datagram have been sent from the network
interface to the network regardless of whether any
Case: 19-1464 Document: 85 Page: 6 Filed: 07/16/2020
6 ALACRITECH, INC. v. INTEL CORP.
corresponding ACK[s] have been received.” J.A. 23. The
Board further found that Connery’s interrupt would be
generated by the network interface prior to receiving an
ACK from the recipient for all of the transmitted data.
Substantial evidence supports the Board’s fact findings.
The Board reasonably found that the interrupt gener-
ated by Connery’s network interface is strictly associated
with the task given to the network interface—transmitting
data in segments—and not other tasks, such as ACK pro-
cessing, that the host computer has not offloaded to the net-
work interface. As Intel’s expert, Dr. Horst, explained,
such an interrupt to indicate that the network interface is
done with segmenting and transmitting data “is needed be-
cause otherwise the host would not know when the [net-
work interface] hardware is free to accept the next large
packet to be sent.” J.A. 1670. In contrast, the Board found
that ACK processing is “unaffected by Connery’s alleged
improvements to segmenting and transmitting data” on
the network interface. J.A. 23. Thus, “an ordinarily skilled
artisan would have presumed ACKs are processed in the
normal processing of a TCP/IP protocol stack operable in
the host computer.” Id. In other words, while Connery con-
templates offloading the task of transmitting data in seg-
ments from the CPU to its network interface, which in turn
sends an interrupt back to the host when that task is com-
plete, ACK processing is not affected; the ACK, as a sepa-
rate message, continues to be sent from the recipient and
handled by the CPU in a conventional manner. Because
ACK processing has not been offloaded from Connery’s
CPU to its network interface, the Board fairly concluded
that the “interrupt” generated by the network interface in-
dicates that the interface has completed its data transmis-
sion assignment rather than referring to the ACK. Thus,
like the Board, we are not persuaded by Alacritech’s argu-
ment that Connery’s interrupt must include the ACK or de-
pend on receipt of the ACK.
Case: 19-1464 Document: 85 Page: 7 Filed: 07/16/2020
ALACRITECH, INC. v. INTEL CORP. 7
After determining that Connery’s “interrupt for trans-
mit complete” is sent by the network interface to the CPU
independently of the receipt of any ACK, the Board consid-
ered the relative timing between the transmit complete in-
terrupt and the return of ACKs for all of the transmitted
data. J.A. 24. We see no error in the Board’s reasoning
that “an interrupt for transmit complete would precede”
the ACK indicating that all data segments of the datagram
have been transmitted “because there is substantial la-
tency in receipt of the ACK as compared to” the interrupt.
Id. After the network interface “transmit[s] the last packet
of the datagram,” the transmit complete interrupt would
be “sent immediately” and “virtually instantaneous” be-
tween the network interface and the CPU, whereas there
would be “substantial latency,” i.e., delay, from the trans-
mission of the last packet of the datagram over the net-
work, the processing of that packet at the receiving
computer, and the return transmission of an ACK for that
packet from the receiving computer to the transmitting
network interface. Id.
Alacritech alleges that, under the Board’s reading,
Connery’s network interface must also generate a second
interrupt “to let the CPU know that the ACKs have been
received and the data transfer is complete,” rendering the
initial transmit complete interrupt “meaningless.” Appel-
lant’s Br. at 20–22. According to Alacritech, the CPU must
wait for this alleged second interrupt indicating receipt of
the ACKs for the first batch of data before “sending the
next batch of data to the [network interface] for transmis-
sion.” Id. We note that Alacritech did not make this “sec-
ond interrupt” argument before the Board, and arguments
not made below are generally waived. In re NuVasive, Inc.,
842 F.3d 1376, 1380 (Fed. Cir. 2016) (“a party waives an
argument that it ‘failed to present to the [PTAB]’ because
it deprives the court of ‘the benefit of the [PTAB]’s informed
judgment’”) (citing In re Watts, 354 F.3d 1362, 1367–68
(Fed. Cir. 2004)). Although Alacritech points out that it
Case: 19-1464 Document: 85 Page: 8 Filed: 07/16/2020
8 ALACRITECH, INC. v. INTEL CORP.
argued to the Board that a skilled artisan would not depart
from the allegedly “conventional” practice in which “the
network interface device waits for an ACK for all the trans-
mitted data before it sends a response indicating the com-
mand has been completed to the local host,” that says
nothing about a second interrupt in addition to Connery’s
or that Connery’s CPU must wait for a second interrupt
before supplying additional data to its network interface
for transmission. Appellant’s Reply Br. at 1–2 (citing J.A.
444). To the extent that Alacritech argued that Connery’s
interrupt is dependent on the receipt of an ACK, we ex-
plained above that substantial evidence supports the
Board’s conclusion that Connery’s interrupt is indicative of
transmit completion rather than ACK receipt.
In any event, nothing in Connery or the record suggests
that Connery’s CPU must wait for ACK confirmation be-
fore supplying additional data to the network interface for
transmission. Alacritech does not contend that the TCP
protocol itself imposes such a requirement on the interac-
tion between the CPU and the network interface. Appel-
lant’s Reply Br. at 8–9 (acknowledging that TCP’s flow
control mechanism, which includes ACKs, “does not specify
the communications between the sending computer’s CPU
and a [network interface card]”). As both parties agree, the
TCP protocol controls the flow of data between transmit-
ting and receiving devices based on a “window” advertised
by the receiving device. The receiving window defines how
much data the transmitting device can send to the receiv-
ing device without waiting for ACKs from the receiving de-
vice. Connery itself explains that the sending computer
can continue to transmit data without waiting for any
ACKs so long as the “sender controls the amount of data
sent onto the network so that it does not exceed the size of
the advertised window of the destination.” Connery at col.
2 ll. 3–13. Connery further confirms that, consistent with
TCP’s constraints on transmitting data, the CPU can
“send[] a plurality of datagrams to the network interface
Case: 19-1464 Document: 85 Page: 9 Filed: 07/16/2020
ALACRITECH, INC. v. INTEL CORP. 9
for the same session,” and the network interface will “con-
catenate[],” i.e., link, “data from the current datagram”
that is sequentially aligned “with data from the following
datagram.” Id. at col. 4 ll. 34–41. As Intel explains, such
concatenation between datagrams would be impossible if,
as Alacritech urges, the following datagram was not made
available to the network interface until after the current
datagram is transmitted and an ACK received.
In sum, the Board’s decision finding that Connery’s in-
terrupt represents the network interface’s completion of
transmission of a large datagram and occurs prior to the
receipt of an ACK for all of the data in that large datagram
is supported by substantial evidence.
CONCLUSION
We have considered Alacritech’s remaining arguments
and find them unpersuasive. For the reasons stated above,
we affirm the Board’s conclusion that the claims at issue
are unpatentable.
AFFIRMED