Google LLC

Patent Trials and Appeals Board

Apr 22, 2020

15396512 - (D) (P.T.A.B. Apr. 22, 2020)

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.
15/396,512 12/31/2016 Abdul Kabbani GOOGLE 3.0F-2664 CON 4538
78792 7590 04/22/2020
GOOGLE
Lerner, David, Littenberg, Krumholz & Mentlik, LLP
20 Commerce Drive
Cranford, NJ 07016
EXAMINER
PATEL, PARTHKUMAR
ART UNIT PAPER NUMBER
2468
NOTIFICATION DATE DELIVERY MODE
04/22/2020 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):
eOfficeAction@lernerdavid.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
________________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
________________

Ex parte ABDUL KABBANI and AMIN VAHDAT
________________

Appeal 2019-005397
Application 15/396,512
Technology Center 2400
________________

BEFORE DENISE M. POTHIER, JOHNNY A. KUMAR, and
BETH Z. SHAW, Administrative Patent Judges.

KUMAR, Administrative Patent Judge.

DECISION ON APPEAL
STATEMENT OF CASE
Introduction
Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals the Final Rejection
of claims 1–14. We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.

1 We use the word “Appellant” to refer to “applicant” as defined in
37 C.F.R. § 1.42. According to Appellant, Google LLC is the real party in
interest. Appeal Br. 1.
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Invention
The invention relates to weighted routing of data traffic in a
multistage network to achieve load balancing. Spec. ¶¶ 2–3; Figs. 2 and 5;
claim 1. In particular, a data switch having a plurality of egress ports
receives a data packet (Spec. ¶¶ 44–45). Based on a hash value produced by
an independent hash function for each of the egress ports (id. at ¶¶ 4, 53),
and a scaling factor to scale the hash value (id.), one of the plurality of
egress ports is selected for sending the data packet. Id.
Claim 1 is illustrative of the invention and is reproduced below, with
bracketing and emphases to indicate limitations in dispute:
1. A method comprising:

receiving, at a data switch, a data packet, the data switch
including a plurality of egress ports;

for a given received data packet:

for each of the egress ports:

[L1] generating, by the data switch, a hash value based
on one or more fields of the given received data packet using [L2] a
hash function assigned to the egress port, wherein the hash function
assigned to each egress port [L3] is independent and different from
the hash functions assigned to each of the other egress ports;

selecting, for the given received data packet, an egress port of
the plurality of egress ports based on the respective hash values for
each of the egress ports generated for the given received data packet;
and

transmitting, by the data switch, the given received data packet
using the selected egress port.

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Appeal Br. 10, Claims Appendix (bracketing and emphases added to
indicate limitations in dispute).

REJECTIONS2
Claims 1 and 8 stand rejected under 35 U.S.C. § 103 as being
unpatentable over Agarwall et al. (US 8,111,649 B1; issued February 7,
2012) (“Agarwall”) in view of S P et al. (US 8,259,585 B1; issued
September 4, 2012) (“Arun”) and Buehrer et al. (US 7,818,303 B2; issued
October 19, 2010) (“Buehrer”) Final Act. 6–11.
Claims 2 and 9 stand rejected under 35 U.S.C. § 103 as being
unpatentable over Agarwall, Arun, Buehrer, and Lamy et al. (US
2006/0198393 A1; published September 7, 2006 (“Lamy”). Final Act. 11–
13.
Claims 3 and 10 stand rejected under 35 U.S.C. § 103 as being
unpatentable over Agarwall, Arun, Buehrer, and So (US 2011/0161657 A1;
published June 30, 2011). Final Act. 13–14.
Claims 4 and 11 stand rejected under 35 U.S.C. § 103 as being
unpatentable over Agarwall, Arun, Buehrer, So, and Kapadia et al. (US
2013/0308455 A1; published November 21, 2013) (“Kapadia”). Final Act.
15–17.
Claims 5 and 12 stand rejected under 35 U.S.C. § 103 as being
unpatentable over Agarwall, Arun, Buehrer, So, and Beshai (US 6,580,721
B1; issued June 17, 2003). Final Act. 17–18.

2 The Examiner withdrew the rejection of claims 1–7 and 9–14 under
35 U.S.C. § 101. See Final Act. 2–4; Ans. 2–3. Therefore, this rejection is
not before us on appeal.
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Claims 6 and 13 stand rejected under 35 U.S.C. § 103 as being
unpatentable over Agarwall, Arun, Buehrer, So, and Schollmeier et al. (US
2009/0116488 A1; published May 7, 2009) (“Schollmeier”). Final Act. 18–
19.
Claims 7 and 14 stand rejected under 35 U.S.C. § 103 as being
unpatentable over Agarwall, Arun, Buehrer, So, and Liu et al. (US
2009/0268674 A1; published October 29, 2009) (“Liu”). Final Act. 19–20.

ANALYSIS
We have only considered those arguments that Appellant actually
raised in the Briefs.3 Arguments Appellant could have made, but chose not
to make, in the Briefs have not been considered and are deemed to be
waived. See 37 C.F.R. § 41.37(c)(1)(iv).

A. Whether the combination of Agarwall, Arun, and Buehrer teaches
claim limitation L1
The Examiner finds that Agarwall teaches, inter alia, “generating, by
the data switch, a hash value” for each of the egress ports as required by
claim 1, because Agarwall teaches “computing a hash value which selects an
output port based in part on a header of the packet.” Final Act. 6–7 (citing to
Agarwall’s claim 11).
Appellant contends that “[t]he Action acknowledges that [Agarwall]
and Arun are silent as to generating a hash value for each of a plurality of

3 In the instant appeal, claims 2–7 and 9–14 are not argued separately from
claims 1 and 8, respectively, in either of Appellant’s briefs (Appeal Br. 3–9;
Reply Br. 2–4), and will not be separately addressed.
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egress ports.” Appeal Br. 6 (citing to Final Act. 8). Appellant argues that the
Examiner cites Buehrer’s claim 6 to provide a teaching for L1, but “there is
no mention [in claim 6 of Buehrer] of generating a hash value for each of a
plurality of egress ports that each have an independent and different hash
function assigned thereto.” Appeal Br. 6–7.
We disagree with Appellant’s argument that the Examiner turns to
Buehrer alone to teach L1. The portion of the Final Action on which the
Appellant relies, states: “Agrawal [sic] is silent regarding generating a hash
value for each of a plurality of egress ports, wherein each egress port is
assigned has [sic] function.” Final Act. 8; see also Appeal Br. 6. Therefore,
the Examiner’s emphasis indicates that the Examiner finds that Agarwall is
silent with respect to each of the egress ports being assigned a hash function.
Moreover, we agree with the Examiner’s finding that Agarwall
teaches the claimed step of “for each of the egress ports: generating, by the
data switch, a hash value.” See Final Act. 6; see id. at 6–7. Namely,
Agarwall’s claim 11 teaches “a selecting-mechanism configured to select an
output port, from the set of output ports, by: computing a hash value which
selects an output port based in part on a header of the packet.” See Agarwall,
claim 11 (emphases added). Therefore, Agarwall at least suggests generating
a hash value for each of the egress ports, in order to select a given egress
port.

B. Whether the combination of Agarwall, Arun, and Buehrer teaches
claim limitations L2 and L3
The Examiner finds that Buehrer teaches L2, because “Buehrer states
in claim 7 that instructions for hashing each link of each respective node
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using k perfect hash functions (assigned ones) [are used] to produce a set of
k hash values for each of the links of each of the respective nodes; further
see claim 6.” Final Act. 8 (emphases removed). The Examiner further finds
that Arun teaches the limitations of L3, because:
Arun teaches that Router 10 i.e.[,] switch here therefore selects
one of links 14 through which to send the packet. To do so,
router 10 applies one of a set of hash functions to the packet.
For IP packets, router 10 may apply the one of the hash
function to the packet header, e.g., the 5-tuple [source IP
address, destination IP address, source port number, destination
port number, protocol]. In one example, the set of hash
functions (i.e.[,] a hash function here) includes two hash
functions, [H.sub.A, H.sub.B], such that for any packet header
PH, H.sub.A(PH) #H.sub.B(PH). In another
example, the set of hash functions includes N hash functions,
[H.sub.A, H.sub.B, . . . H.sub.N], such that for any packet
header PH, H.sub.A(PH) #H.sub.B(PH) # . . . #H.sub.N(PH) . .
. no two of the hash functions produce the same result when
applied to a packet header; see lines 20 -35 of col. 6; further
see lines 48- 51 of col. 6; by selecting different hash functions
for different packet flows, as described herein, router 10 may
achieve load balancing.

Final Act. 7–8 (original emphases omitted; emphases added).
The Appellant argues that “Bueher [sic] fails to assign different hash
functions to different egress ports of a data switch. Buehrer, instead, applies
an identical set of K hash functions to all links of [a] node to produce a set of
K hash values for each link of each node.” Appeal Br. 6 (emphases omitted)
(citing to Buehrer 4:38–49, Fig. 10 (step 1002)). As such, Appellant
contends that the hash functions of Buehrer are not independent and
different. Id.
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In response to the Examiner’s findings with respect to Arun,
Appellant argues that “Arun discusses selecting a single hash function to
apply to a packet based on the application of a Bloom filter to a 5-tuple of
data fields in the header of the packet being forwarded.” Appeal Br. 5–6. In
other words, “Arun uses one has [sic] function to select a link through which
to send the packet. Arun nowhere mentions that each link is assigned its own
hash function.” Id. at 6. In sum, Appellant argues that the Examiner:
appears to contend that Arun teaches selecting different hash
functions for different packet flows, and that [Buehrer] teaches
hashing each link of each respective node, and that somehow
these teachings can be combined to read on a “hash function
assigned to each egress port” wherein the hash function for one
egress port “is independent and different from the hash
functions assigned to each of the other egress ports” as recited
in claim 1.

Reply Br. 2.
We disagree with Appellant. Based on the record before us,
Appellant’s arguments do not apprise us that the Examiner erred in finding
that the combination of Agarwall, Arun, and Buehrer teach the disputed
limitations L2 and L3. More particularly, Appellant’s arguments with
respect to Buehrer and Arun do not reflect the specific findings made by the
Examiner.
Appellant’s arguments that (1) Buehrer does not teach “different”
hash functions assigned to “different” egress ports (Appeal Br. 6); (2)
Buehrer applies an “identical” set of hash functions to all links of a node
(id.); (3) the hash functions of Buehrer are not “independent and different”
(id.; see also Reply Br. 3); and (4) Buehrer teaches using “the same set of
hashes” for the links (Reply Br. 3), are arguments that Buehrer does not
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teach the limitations L3. But the Examiner finds that Arun, rather than
Buehrer, teaches L3. See Final Act. 7–8. Therefore, Appellant’s arguments
amount to an attack on Buehrer, where the Examiner relies upon the
combination of references to teach L2 and L3. One cannot show
nonobviousness by attacking references individually where the rejections are
based on combinations of references. In re Keller, 642 F.2d 413, (CCPA
1981); In re Merck & Co., Inc., 800 F.2d 1091 (Fed. Cir. 1986).
Similarly, Appellant’s argument that “Arun nowhere mentions that
each link is assigned its own hash function” (Appeal Br. 6) attacks Arun for
not teaching L2. Here, however, the Examiner finds that Buehrer in
combination with Agarwall and Arun to teach L2. Final Act. 8–9.
To the extent that Appellant argues that “Arun discusses selecting a
single hash function to apply to a packet” (Appeal Br. 5 (emphases added)),
and that “Arun uses one has [sic] function to select a link through which to
send the packet” (id. at 6 (emphasis added)), such alleged teaching in Arun
does not negate the Examiner’s finding that Arun teaches that each hash
function is independent and different, as required by L3. See Final Act. 7–8.
Appellant’s further arguments directed to Arun, namely that
“[a]ssigning hash functions to egress ports is separate and distinct from
selecting hash functions for packet flows” (Reply Br. 3), and “Arun does not
state that the hash function applied to one packet flow is ‘independent and
different from the hash functions assigned to each of the other’ packet
flows” (id.), ignore the combined teachings of Agarwall, Arun, and Buehrer.
Specifically, we find no error with the Examiner’s proffered findings and
conclusions that an ordinarily skilled artisan would have had motivation to
apply the teachings of Buehrer—a hash function assigned to each egress port
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(see Final Act. 8–9)—and the teachings of Arun—each hash function is
independent and different from the other hash functions (id. at 7–8)—
collectively to arrive at the claimed L2 and L3. Appellant’s argument,
therefore, is not persuasive to show that the Examiner erred in finding that
Arun teaches L3. Accordingly, based on the evidence before us, we are not
persuaded that the Examiner erred in finding that the combination of
Agarwall, Arun, and Buehrer teaches L2 and L3.
In addition, we note that Figure 6 of Arun, and the corresponding
description of Figure 6 in column 17, lines 3–19 of Arun, though not relied
upon by the Examiner, appears to teach both L2 and L3. In particular, Figure
6 shows a hash function (#172A, 172B) assigned to each of the egress ports
(#172A is assigned to egress port #180C, and #172B is assigned to egress
port #180B; further egress ports #180C – #180M also appear to have their
own hash functions) that is independent and different (see Arun Fig. 6 and
17:3–19) from the hash functions assigned to each of the other egress ports.
Id.

C. Whether Buehrer is analogous art
The Examiner finds that Buehrer is analogous art, because Buehrer
teaches:
network 202 [which] may be a single network or a
combination of networks, such as, for example, the Internet
or other networks. Network 102 may include a wireless
network, a wired network, a packet-switching network, a
public switched telecommunications network, a fiber-optic
network, other types of networks, or any combination of the
above . . . further #180 interface includes a transceiver for
communicating via one or more networks via wired, wireless,
fiber optic, or other connection.
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Ans. 8 (citing to Buehrer at Figure 2, 4:1–12, and 3:45–59).
Appellant disagrees, arguing that Buehrer is not analogous art, and is
instead directed to “methods and processing devices for ‘compressing a web
graph including multiple nodes and links between the multiple nodes’ . . .
not for making packet forwarding decisions. Accordingly, Buehrer pertains
to a different field of endeavor, in particular web structure analysis rather
than packet forwarding.” Appeal Br. 8 (citation omitted). Appellant
additionally argues that Buehrer, directed to “clustering links in a web graph
to compress such a graph,” would not have logically commended itself to the
problem of “determin[ing] which egress port to forward a packet over.” Id.
Whether a prior art reference is analogous is a two-prong test: “(1)
whether the art is from the same field of endeavor, regardless of the problem
addressed and, (2) if the reference is not within the field of the
inventor’s endeavor, whether the reference still is reasonably pertinent to the
particular problem with which the inventor is involved.” In re Klein, 647
F.3d 1343, 1348 (Fed. Cir. 2011) (citation and quotations omitted.). Our
reviewing court further guides that “[a] reference is reasonably pertinent if,
even though it may be in a different field from that of the inventor’s
endeavor, it is one which, because of the matter with which it deals,
logically would have commended itself to an inventor’s attention in
considering his problem.” In re Clay, 966 F.2d 656, 659 (Fed. Cir. 1992).
The Supreme Court additionally guides that “familiar items may have
obvious uses beyond their primary purposes.” KSR Int’l Co. v. Teleflex, Inc.,
550 U.S. 398, 402 (2007).
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Applying the guidance above, we determine that Buehrer satisfies at
least the second prong of the two-prong test articulated by the court in Klein.
Buehrer explicitly teaches, in one embodiment, using a “packet-switching
network” (Buehrer at 4:10), i.e., a network for sending a data packet. See
also Ans. 8. Thus, we find that Buehrer is in the same general field of
endeavor as the claimed invention—or at least reasonably pertinent to the
problem the inventor is trying to solve (see Spec. ¶ 4 (summarizing the
invention as a technique for routing data packets in a network))—and do not
find Appellant’s arguments that Buehrer is non-analogous art to be
convincing.
Accordingly, we sustain the Examiner’s obviousness rejection of
claim 1. Arguments related to the rejection of independent claim 8, which
contains similar limitations and is rejected over the same combination of
prior art, refer to the arguments presented for claim 1. See Appeal Br. 8–9.
Similarly, Appellant relies on the arguments presented for claims 1 and 8
when discussing dependent claims 2–7 and 9–14. Id. at 9. Accordingly, we
affirm the Examiner’s rejections of claims 1–14.

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CONCLUSION
In summary:

No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C. F.R. § 1.136(a).

AFFIRMED

Claim(s)
Rejected
35 U.S.C.
§
Reference(s)/Basis Affirmed Reversed
1, 8 103 Agarwall, Arun,
Buehrer
1, 8
2, 9 103 Agarwall, Arun,
Buehrer, Lamy
2, 9
3, 10 103 Agarwall, Arun,
Buehrer, So
3, 10
4, 11 103 Agarwall, Arun,
Buehrer, So,
Kapadia
4, 11
5, 12 103 Agarwall, Arun,
Buehrer, So,
Beshai
5, 12
6, 13 103 Agarwall, Arun,
Buehrer, So,
Schollmeier
6, 13
7, 14 103 Agarwall, Arun,
Buehrer, So, Liu
7, 14
Overall
Outcome
1–14