VMware, Inc.

Patent Trials and Appeals Board

Jan 19, 2021

2019005568 (P.T.A.B. Jan. 19, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
14/628,137 02/20/2015 Lizhu Zhang C176 9422
152689 7590 01/19/2021
Novum Patent Services
515 Powhattan Ave
San Francisco, CA 94110
EXAMINER
SPRATT, BEAU D
ART UNIT PAPER NUMBER
2143
NOTIFICATION DATE DELIVERY MODE
01/19/2021 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
aram@novumpatent.com
ipadmin@vmware.com
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte LIZHU ZHANG
____________

Appeal 2019-005568
Application 14/628,137
Technology Center 2100
____________

Before KARA L. SZPONDOWSKI, SCOTT B. HOWARD, and
STEVEN M. AMUNDSON, Administrative Patent Judges.

AMUNDSON, Administrative Patent Judge.

DECISION ON APPEAL
Appellant1 seeks our review under 35 U.S.C. § 134(a) from a final
rejection of claims 1–5, 7–12, and 14–22, i.e., all pending claims. We have
jurisdiction under 35 U.S.C. § 6(b).
We reverse.

1 We use the word “Appellant” to refer to “applicant” as defined in
37 C.F.R. § 1.42 (2018). Appellant identifies the real party in interest
as VMware, Inc. Appeal Br. 3.
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STATEMENT OF THE CASE
The Invention
According to the Specification, the invention “generally relates to
caching image data and more particularly relates to enabling multiple client
devices to share image cache data in remote desktop environments.” Spec.
¶ 1.2 The Specification explains that “remote desktop environments, such
as those based on Virtual Desktop Infrastructure (VDI) and Desktop-as-a-
Service (DAAS)” allow users to access “their virtual desktop[s] over a
remote network connection.” Id. ¶ 2. Using “a remote desktop protocol, the
user can interact with applications of the virtual desktop, which are running
on the remote host server, such that only the display (i.e., image data),
keyboard, and mouse information is communicated with the local client
device.” Id.
The Specification also explains that remote desktop environments
still present “a number of inconveniences and inefficiencies,” e.g., due to
“bandwidth and latency limitations.” Spec. ¶ 4; see id. ¶ 13. For instance,
“network limitations may cause the interface presented at the client device to
appear choppy, visually distorted or unresponsive at times” because “large
amounts of image data need to be communicated from the virtual desktop
to the client device.” Id. ¶ 4.
Hence, the invention endeavors to “deliver the image information to
the client device” more efficiently to “improve the experience of the end

2 This decision uses the following abbreviations: “Spec.” for the
Specification, filed February 20, 2015; “Final Act.” for the Final Office
Action, mailed November 5, 2018; “Appeal Br.” for the Appeal Brief, filed
April 5, 2019; “Ans.” for the Examiner’s Answer, mailed May 13, 2019; and
“Reply Br.” for the Reply Brief, filed July 15, 2019.
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user accessing the virtual desktop.” Spec. ¶ 4. For example, client devices
typically connect to a remote server through a wide area network (WAN)
connection, e.g., an Internet connection. Id. Thus, “enabling a client device
to obtain the necessary image data” from another client device through a
local area network (LAN) connection “can drastically improve the speed of
delivery of the required image data” because “WAN connections are usually
orders of magnitude slower than LAN connections.” Id. ¶ 15.
Exemplary Claim
Independent claim 1 exemplifies the claims at issue and reads
as follows:
1. A method for providing image cache collaboration
between multiple client devices in a remote desktop
environment, the method comprising:
detecting, by a virtual desktop agent executing on a host
server, an update to at least a portion of a graphical user
interface (GUI) of a virtual desktop executed on the host server
for a first client device;
transmitting an image hash key of the update from the
virtual desktop agent executing on the host server to a central
cache manager executing on a connection server, wherein the
connection server is a separate device from the host server and
is configured to establish virtual desktop connection sessions
for each of the client devices;
determining, by the central cache manager, that an image
cache on a second client device currently contains image data
needed to update the GUI of the virtual desktop for the first
client device, wherein the central cache manager knows the
contents of all image caches of each of the client devices that
are connected to the connection server by using an agreed upon
caching algorithm between the central cache manager and the
client devices, wherein the agreed upon caching algorithm
enables the central cache manager to determine, at the time of
transmitting the image data to the client devices, whether the
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image data will be cached by the client devices; and
transmitting a message, from the central cache manager
executing on the connection server to the first client device
identifying the second client device that contains the image
data, wherein the first client device requests the image data
from the second client device in response to receiving said
message.
Appeal Br. 15 (Claims App.).
The Prior Art Supporting the Rejection on Appeal
As evidence of unpatentability under 35 U.S.C. § 103, the Examiner
relies on the following prior art:
The Rejection on Appeal
Claims 1–5, 7–12, and 14–22 stand rejected under 35 U.S.C. § 103
as unpatentable over Luxenberg and Anderson. Final Act. 2–19.
ANALYSIS
We have reviewed the § 103 rejection in light of Appellant’s
arguments that the Examiner erred. Based on the record before us and for
the reasons explained below, we agree with Appellant’s arguments that the
Examiner erred in finding that the cited portions of the references teach or
suggest the claimed subject matter. We provide the following to address and
emphasize specific findings and arguments.
Independent Claims 1, 8, and 15
As noted above, the § 103 rejection of independent claims 1, 8, and 15
rests on Luxenberg and Anderson. See Final Act. 3–5, 8–10, 13–16.
Name Reference Date
Anderson et al. (“Anderson”) US 2010/0235581 A1 Sept. 16, 2010
Luxenberg et al. (“Luxenberg”) US 2014/0156778 A1 June 5, 2014
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Appellant argues that the Examiner erred in rejecting the claims because the
references fail to teach or suggest the following limitations in each claim:
wherein the central cache manager knows the contents of all
image caches of each of the client devices that are connected
to the connection server by using an agreed upon caching
algorithm between the central cache manager and the client
devices, wherein the agreed upon caching algorithm enables the
central cache manager to determine, at the time of transmitting
the image data to the client devices, whether the image data will
be cached by the client devices.
See Appeal Br. 8–12; Reply Br. 1–3.
In particular, Appellant contends that the claims require an “agreed
upon” algorithm so that “the central cache manager can determine ‘at the
time of transmitting the image data’ whether the transmitted image data will
be cached by the client devices” without “needing to communicate with the
client devices to check whether the image data is actually cached on the
client devices.” Appeal Br. 9. Appellant also contends that applying an
“agreed upon” algorithm “means using the same caching logic agreed by the
central cache manager and the client devices to determine whether the client
devices will cache the data, before the data is actually cached.” Id. at 10.
According to Appellant, “the central cache manager applies the same
algorithm that is used by the client devices to determine whether or not any
particular image data that is being transmitted to a client device will be
cached by the client device.” Appeal Br. 9. Appellant asserts that by
applying the same algorithm “the central cache manager keeps track of the
contents of each of the client devices by using the agreed upon caching
algorithm” without “needing to query or receive updates about actual cache
contents from the client devices themselves.” Id.
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Appellant seeks to distinguish the claims from the references by
asserting that the references “discuss other approaches, such as ones where
the server is notified of cache contents of client devices by communicating
with the client devices” instead of “applying an agreed upon algorithm.”
Appeal Br. 9; see Reply Br. 2–3. Specifically, Appellant concedes that
Luxenberg discloses “a cache manager that tracks which objects are
provided to which clients.” Appeal Br. 11 (citing Luxenberg ¶ 12; Final
Act. 21); see Reply Br. 3. But Appellant contends that Luxenberg does not
disclose:
(1) “how the cache manager tracks caches”;
(2) “that tracking is performed by using an agreed upon
caching algorithm between the central cache manager
and the client devices”; or
(3) “that the central cache manager uses the agreed upon
caching algorithm to determine, at the time of
transmitting the image data to the client devices,
whether the image data will be cached by the client
devices.”
Appeal Br. 11–12; see Reply Br. 3.
Appellant asserts that Anderson discloses (1) “that client devices
communicate changes in cache contents to the directory server” and
(2) “that the directory server can determine how to evict cached content
when requested by a client.” Appeal Br. 10–11 (citing Anderson ¶¶ 21,
41–42); see Reply Br. 2. Appellant also asserts that Anderson does not
disclose an “agreement to use a particular algorithm” when client devices
update a distributed hash table with information to track locations of cached
data. Appeal Br. 9–10 (citing Anderson ¶ 20).
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The Examiner determines that Luxenberg discloses “a cache manager
that tracks which objects are provided to which clients.” Final Act. 21
(citing Luxenberg ¶ 12); Ans. 22–23 (citing Luxenberg ¶ 12). In addition,
the Examiner determines that Anderson discloses “a ‘cooperative caching
algorithm’ and such an algorithm does not contradict ‘an agreed upon
algorithm’ since this cooperation requires that both clients [and] a server
agree to cache with each other and peers and still be managed.” Ans. 22
(citing Anderson ¶¶ 14, 20–21, 41–42); see Final Act. 4–5, 10, 15–16, 21.
Based on the record before us, we agree with Appellant that the
Examiner has not adequately explained how the cited portions of Luxenberg
and Anderson teach or suggest the disputed limitations in claims 1, 8,
and 15.
Luxenberg discloses a cache manager that (1) “may track and/or
manage which graphical objects have been provided to which clients” and
(2) “may manage and/or track the caches distributed across multiple clients
(e.g., may manage a distributed cache).” Luxenberg ¶ 12. In the cited
portions, however, Luxenberg does not disclose that the cache manager and
the client devices use the same “agreed upon” algorithm to enable the cache
manager “to determine, at the time of transmitting the image data to the
client devices, whether the image data will be cached by the client devices”
as required by the claims.
Anderson discloses “a cooperative caching scheme” where “every
client dedicates a portion of its main memory to caching and attempts to
satisfy requests from its peers for system contents.” Anderson ¶ 14. The
system includes a directory server that “manage[s] communications among
the clients” and (2) “track[s] locations of cached data.” Id. ¶ 20. The
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directory server includes a directory with one or more tables mapping
cached-data identifiers to clients. Id. ¶ 21; see id. ¶ 41. “When a client’s
cache contents change, the change is communicated to the directory server”
so that the directory server “may update its directory.” Id. Further, “the
clients may participate in management of communications regarding cached
data” using “a distributed hash table” to track locations of cached data. Id.
¶ 20. In addition, the directory server may respond to an eviction notice
from a client by “identifying a target client” to receive evicted data. Id.
¶¶ 41–42, Fig. 5.
In the cited portions, however, Anderson does not disclose that the
directory server and the client devices use the same “agreed upon” algorithm
to enable the directory server “to determine, at the time of transmitting the
image data to the client devices, whether the image data will be cached by
the client devices” as required by the claims. For instance, if the directory
server and the client devices used the same “agreed upon” algorithm, the
directory server would not need to receive a communication from a client
device when its cache contents changed. Further, client devices using
“a distributed hash table” to track locations of cached data differ from
the directory server and the client devices using the same “agreed upon”
algorithm that enables a determination about whether the data will be cached
“at the time of transmitting” the data. In addition, the directory server
“identifying a target client” to receive evicted data differs from the directory
server and the client devices using the same “agreed upon” algorithm that
enables a determination about whether the data will be cached “at the time of
transmitting” the data.
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Because the Examiner has not adequately explained how the cited
portions of Luxenberg and Anderson teach or suggest the disputed
limitations in claims 1, 8, and 15, we do not sustain the § 103 rejection
of these independent claims.
Dependent Claims 2–5, 7, 9–12, 14, and 16–22
Claims 2–5, 7, and 21 depend directly or indirectly from claim 1;
claims 9–12, 14, and 22 depend directly or indirectly from claim 8; and
claims 16–20 depend directly or indirectly from claim 15. For the reasons
discussed for claims 1, 8, and 15, we do not sustain the § 103 rejection of
these dependent claims.
CONCLUSION
We reverse the Examiner’s decision to reject claims 1–5, 7–12, and
14–22.
In summary:
Claims
Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1–5, 7–12,
14–22 103
Luxenberg,
Anderson
1–5, 7–12,
14–22
REVERSED