Ex Parte Pan et al

Board of Patent Appeals and Interferences

Jan 26, 2010

10153922 (B.P.A.I. Jan. 26, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte JIE PAN, SCOTT R. KOTRLA, and LOUIS A. MCKEAGUE
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Appeal 2009-005457
Application 10/153,9221
Technology Center 2600
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Decided: January 26, 2010
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Before ROBERT E. NAPPI, MARC S. HOFF,
and CARL W. WHITEHEAD, JR., Administrative Patent Judges.

HOFF, Administrative Patent Judge.

DECISION ON APPEAL

1 The real party in interest is Verizon Business Global LLC, a wholly owned
subsidiary of Verizon Communications Inc.
Appeal 2009-005457
Application 10/153,922

STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134 from a Final Rejection of
claims 1-10, 13-18, and 21-29. We have jurisdiction under 35 U.S.C. § 6(b).
We reverse.
Appellants’ invention concerns a network device that controls the
flow of traffic in a network, such as an Ethernet-based network. The
network device detects congestion in the network and identifies at least one
upstream device to which to send a flow control message, wherein the
upstream device is a device that is transmitting above a predetermined level.
The network device transmits to the identified upstream device the flow
control message which instructs the identified upstream device to slow down
transmissions to the network device (Abstract, Spec. ¶¶ [0008], [0009]).
Claim 1 is exemplary:
1. A network device comprising:
at least two input interfaces;
at least one output interface;
a link monitoring unit configured to:
monitor traffic flow received at the at least two input interfaces, and
monitor traffic flow transmitted from the at least one output interface;
and
a flow control unit configured to:
detect congestion on the at least one output interface based on the
monitoring of the at least one output interface, and
selectively transmit a flow control signal to one or more upstream
network devices, the one or more upstream network devices including
network devices that are transmitting above a guaranteed service rate.

The prior art relied upon by the Examiner in rejecting the claims on
appeal is:
Linville US 6,170,022 B1 Jan. 2, 2001
Clarke US 2002/0035642 A1 Mar. 21, 2002
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McAlpine US 2002/0141427 A1 Oct. 3, 2002
Abdelilah US 2003/0012137 A1 Jan. 16, 2003
Joung US 6,628,613 Sep. 30, 2003

Claims 5-10 stand rejected under 35 U.S.C. 103(a) as being
unpatentable over Clarke in view of McAlpine.
Claims 23-28 stand rejected under 35 U.S.C. 103(a) as being
unpatentable over Clarke in view of Linville.
Claims 1-3, 13, 15-18, 21, and 22 stand rejected under 35 U.S.C.
103(a) as being unpatentable over Clarke in view of McAlpine and further in
view of Linville.
Claim 4 stands rejected under 35 U.S.C. 103(a) as being unpatentable
over Clarke in view of McAlpine and further in view of Linville and Joung.
Claim 14 stands rejected under 35 U.S.C. 103(a) as being
unpatentable over Clarke in view of McAlpine and further in view of
Linville and Abdelilah.
Claim 29 stands rejected under 35 U.S.C. 103(a) as being
unpatentable over Clarke in view of Linville and further in view of
Abdelilah.
Rather than repeat the arguments of Appellants or the Examiner, we
make reference to the Appeal Brief (filed August 21, 2007), and the
Examiner’s Answer (mailed November 2, 2007) for their respective details.

ISSUES
Appellants contend that the combination of Clarke and McAlpine do
not disclose nor suggest transmitting a flow control signal to an upstream
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node that transmits “above a guaranteed service rate,” that the claims recite
(App. Br. 7). Appellants contend that the combination of Clarke and
Linville do not disclose nor suggest transmitting a flow control signal to at
least one upstream device “transmitting above a predetermined level,” that
the claims recite (App. Br. 14).
The Examiner finds that McAlpine teaches that that "queue depth
exceeding one of the status thresholds" indeed satisfies the limitation "above
a guaranteed service rate" ( i.e. the queue depth); since the word "threshold"
is a region marking a boundary, above or below which, conditions will not
be met (Ans. 17). The Examiner finds that a "guaranteed service rate" is a
region marking a boundary of rate, above or below which the service will be
violating the contract. As such the Examiner submits the threshold disclosed
in McAlpine is the same as the “guaranteed service rate” required by the
claims (Ans. 17). The Examiner finds the Linville discloses sending a flow
control message to at least one upstream device that is “transmitting above a
predetermined level” (Ans. 6).
Appellants’ contentions present us with the following two issues:
1. Did Appellants show that the Examiner erred in finding that Clarke
in combination with McAlpine teaches transmitting flow control messages to
one or more upstream nodes that are transmitting above a guaranteed service
rate?
2. Did Appellants show that the Examiner erred in finding that Clarke
in combination with Linville teaches sending a flow control message to at
least one upstream device that is transmitting above a predetermined level?

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FINDINGS OF FACT
The following Findings of Fact (FF) are shown by a preponderance of
the evidence.
The Invention
1. According to Appellants, the invention concerns a network
device that controls the flow of traffic in a network, such as an Ethernet-
based network. The network device detects congestion in the network and
identifies at least one upstream device to which to send a flow control
message, wherein the upstream device is a device that is transmitting above
a predetermined level. The network device transmits to the identified
upstream device the flow control message which instructs the identified
upstream device to slow down transmissions to the network device
(Abstract, Spec. ¶¶ [0008], [0009]).
Clarke
2. Clarke teaches an origin server 16 receives a request from client
11 that it is temporarily unable to handle, and in response, returns an error
response to client 11 indicating a back-off period. This response is passed
down stream through a proxy 14, which recognizes this response type and
learns the back-off time for the origin server 16 before forwarding the
response to client 11 (¶ [0025]).
3. Clarke teaches that each data communication device is a device
suitable for enabling the processing system to communicate with remote
devices and may be, for example, a conventional modem, a Digital
Subscriber Line (DSL) modem, a cable modem, an Ethernet adapter, an
Integrated Services Digital Network (ISDN) adapter, a wireless transceiver
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(e.g., in the case of a mobile device), a satellite transceiver, or the like
(¶ [0041]).

McAlpine
4. McAlpine teaches a pause based link level flow control
applicable to Ethernet architectures, wherein each of the input interfaces
may be initialized with virtual input queues. Each virtual input queue may
be initialized with a queue size and a set of queue status thresholds and have
a queue depth counter set to zero. When a packet conceptually enters a
virtual input queue, the queue depth may be increased. When the packet
gets transmitted out of the switch element, the queue depth may be
decreased. When the queue depth exceeds one of the status thresholds,
pause messages may be transmitted over the upstream link at a certain rate
with each message indicating a quantum of time to pause transmission of
packets to the corresponding virtual input queue. (¶ [0064]).

Linville
5. Linville teaches a process performed by an application program
70 executing in the node, which includes a congestion detector component
72, a traffic monitor 74, pause time logic 76, and a pause transmission logic
78; wherein the congestion detector 72 may use any suitable technique to
provide an indication of congestion at the node. One commonly employed
technique is to monitor the occupancy levels (amount of buffered data) of
the output buffers 68; wherein a threshold occupancy level is defined. As
long as the occupancy level of a buffer remains below this threshold, the
output link served by the buffer is considered to be congestion-free and no
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flow control actions are performed. If, however, the buffer becomes
occupied beyond the threshold occupancy level, the link is considered to be
congested and flow control operations may be initiated. (col. 5, ll. 34-49,
col. 6, ll. 14-21, col. 6, ll. 50-53).
Joung
6. Joung teaches an Ethernet switch for both downstream and
upstream that includes a common buffer 20, a host processor 26, and a MAC
unit 28; wherein the common buffer 20 includes a packet memory 22 for
storing all packet data received via a plurality of input ports of the Ethernet
switch, and a packet memory interface 24 for interfacing between the packet
memory 22 and the MAC unit 28. The packet memory interface 24 includes
an up/down counter. The up/down counter counts up/down upon
enqueueing/dequeueing the packet data in/from the packet memory 22. That
is, the counter counts up when storing the packet data in the memory 22 and
counts down when reading the packet data from the memory 22. If a value
for the up/down counter reaches a predetermined threshold value, the packet
memory interface 24 transmits a signal (buffer_full) to the MAC unit 28,
indicating that buffer is full. The count value is compared to the
predetermined threshold value at every count up/down operation. The
predetermined threshold value is set by an operator of the system to indicate
when the packet memory 22 becomes full. The packet memory interface 24
performs the operation of comparing the count value with the predetermined
threshold value, and transmits the buff-full signal when the count value
exceeds the predetermined threshold value (col. 3, ll. 30-53).
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Abdelilah
7. Abdelilah teaches when an associated flow-control mechanism
detects network congestion or a trend toward network congestion, the
mechanism discards congestion control packets (¶ [0024]).

PRINCIPLES OF LAW
On the issue of obviousness pursuant to 35 U.S.C § 103, the Supreme
Court has stated that “the obviousness analysis cannot be confined by a
formalistic conception of the words teaching, suggestion, and motivation.”
KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 419 (2007). Further, the Court
stated “[t]he combination of familiar elements according to known methods
is likely to be obvious when it does no more than yield predictable results.”
Id. at 416. “One of the ways in which a patent’s subject matter can be
proved obvious is by noting that there existed at the time of the invention a
known problem for which there was an obvious solution encompassed by the
patent’s claims.” Id. at 419-420.
The determination of obviousness must consider, inter alia, whether a
person of ordinary skill in the art would have been motivated to combine the
prior art to achieve the claimed invention and whether there would have
been a reasonable expectation of success in doing so. Brown & Williamson
Tobacco Corp. v. Philip Morris Inc., 229 F.3d 1120, 1125 (Fed. Cir. 2000).
Where the teachings of two or more prior art references conflict, the
Examiner must weigh the power of each reference to suggest solutions to
one of ordinary skill in the art, considering the degree to which one
reference might accurately discredit another. In re Young, 927 F.2d 588,
591 (Fed. Cir. 1991). If the proposed modification would render the prior
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art invention being modified unsatisfactory for its intended purpose, then
there is no suggestion or motivation to make the proposed modification. In
re Gordon, 733 F.2d 900, 902 (Fed. Cir. 1984). Further, our reviewing court
has held that “[a] reference may be said to teach away when a person of
ordinary skill, upon reading the reference, would be discouraged from
following the path set out in the reference, or would be led in a direction
divergent from the path that was taken by the applicant.” In re Gurley, 27
F.3d 551, 553 (Fed. Cir. 1994); Para-Ordnance Mfg., Inc. v. SGS Importers
Int’l., Inc., 73 F.3d 1085, 1090 (Fed. Cir. 1995).

ANALYSIS
Claims 5-10
Claim 5 recites “selectively transmitting flow control messages to one
or more upstream nodes, the one or more upstream nodes including nodes
that are transmitting above a guaranteed service rate.” Claims 6-10 depend
from claim 5.
The Examiner finds that McAlpine teaches a pause based link level
flow control having virtual input queues, wherein, when the queue depth
exceeds one of the status thresholds, pause messages may be transmitted
over an upstream link (Ans. 4, FF 4). The Examiner finds that since the
word "threshold" is a region marking a boundary, above (or below) which a
condition will not be met and “guaranteed service rate" is a region marking a
boundary of rate above (or below) which the service will be violating the
contract, the threshold disclosed in McAlpine satisfies the limitation of
“transmitting above a guaranteed service rate" (Ans. 17).
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Appellants contend that the combination of Clarke and McAlpine
does not disclose nor suggest transmitting a flow control signal to an
upstream node that transmits “above a guaranteed service rate,” as the
claims recite (App. Br. 7). Appellants contend that transmitting pause
messages when a virtual input queue reaches a threshold does not equate to
selectively transmitting flow control messages to one or more upstream
nodes, where the one or more upstream nodes include nodes that are
transmitting above a guaranteed service rate as recited by claim 5 (App. Br.
8).
We agree with Appellants that an upstream device transmitting above
a guaranteed service rate as required by claim 5 and a status threshold for a
queue buffer disclosed in McAlpine are not equivalent. The threshold
disclosed in McAlpine refers to the queue buffer’s depth prior to the time
when a pause message may be transmitted over the upstream link [FF 4].
The threshold disclosed in McAlpine does not refer to the rate at which the
pause message is transmitted over the upstream link [FF 4].
We find that the combined teachings of Clarke and McAlpine do not
disclose all the limitations of claim 5. Thus, we find error in the Examiner’s
rejection of claim 5, as well as claims 6-10 dependent therefrom, under 35
U.S.C. § 103(a) as unpatentable over Clarke in view of McAlpine, and we
will not sustain the rejection.

Claims 23-28
Claim 23 recites “identifying at least one upstream device to which to
send a flow control message when congestion in the network is detected, the
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at least one upstream device being a device that is transmitting above a
predetermined level.” Claims 24-28 depend from claim 23.
The Examiner finds that Linville teaches a link monitoring unit 74 and
a flow control unit 72 and at least one upstream device being a device that is
transmitting above a predetermined level (Ans. 6-7, FF 5). The Examiner
further finds that Linville teaches that as long as the occupancy level of a
buffer remains below this threshold (i.e. a predetermined level), the output
link served by the buffer is considered to be congestion-free, and no flow
control actions are performed. If, however, the buffer becomes occupied
beyond the threshold occupancy level (i.e. a predetermined level), the link is
considered to be congested and flow control operations may be initiated
(Ans. 23).
Appellants contend that the combination of Clarke and Linville does
not disclose nor suggest transmitting a flow control signal to “at least one
upstream device being a device that is transmitting above a predetermined
level,” as the claims recite (App. Br. 11). Appellants further contend that
Linville discloses that a buffer is determined to be congested when the
buffer becomes occupied beyond a threshold occupancy level which differs
from an upstream device that transmits above a predetermined level (App.
Br. 13-14).
We agree with Appellants that Linville does not disclose nor suggest
an upstream device transmitting above a predetermined threshold level as
required by claim 23. Specifically, Linville discloses determining
congestion when the buffer is occupied beyond a predetermined threshold
level, not an upstream device transmitting above a predetermined level
(FF5).
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We find that the combined teachings of Clarke and Linville do not
disclose all the limitations of claim 23. Thus, we find error in the
Examiner’s rejection of claim 23, as well as claims 24-28 dependent
therefrom, under 35 U.S.C. § 103(a) as unpatentable over Clarke in view of
Linville, and we will not sustain the rejections.

Claims 1-3, 13, 15-18, 21, and 22
Claim 1 recites “selectively transmit a flow control signal to one or
more upstream devices, the one or more upstream devices including network
devices that are transmitting above a guaranteed service rate.” Claims 2-3
depend from claim 1.
Claim 5 recites “selectively transmitting flow control messages to one
or more upstream nodes, the one or more upstream nodes including nodes
that are transmitting above a guaranteed service rate.” Claim 13 depends
from claim 5.
Claim 15 recites “identify one or more upstream network devices to
which to transmit a flow control signal based on the at least one control
policy, the control policy causing the flow control unit to identify upstream
network devices that are transmitting above a predetermined threshold.”
Claims 16-18, 21, and 22 depend from claim 15.
The Examiner finds that McAlpine teaches a pause based link level
flow control having virtual input queues, wherein, when the queue depth
exceeds one of the status thresholds, pause messages may be transmitted
over an upstream link (Ans. 10, FF 4). The Examiner finds that since the
word "threshold" is a region marking a boundary, above (or below) which,
conditions will not be met and “guaranteed service rate" is a region marking
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a boundary of rate, above (or below) which the service will be violating the
contract, the threshold disclosed in McAlpine satisfies the limitation of
“transmitting above a guaranteed service rate" (Ans. 36).
Appellants contend that the combination of Clarke, McAlpine, and
Linville does not disclose nor suggest transmitting a flow control signal to
an upstream node that transmits “above a guaranteed service rate,” as the
claims recite (App. Br. 17). Appellants contend that transmitting pause
messages when a virtual input queue reaches a threshold does not equate to
selectively transmitting flow control messages to one or more upstream
nodes, where the one or more upstream nodes include nodes that are
transmitting above a guaranteed service rate as recited by claim 1 (App. Br.
17). Appellants contend further that the combination of Clarke, McAlpine,
and Linville does not disclose nor suggest features of claim 15 that are
similar to claim 1 (App. Br. 20).
We agree with Appellants that the upstream device transmitting above
a guaranteed service rate as required by claim 1 and a status threshold for a
queue buffer disclosed in McAlpine are not equivalent. With respect to
claim 15, for the reasons discussed supra with respect to claim 23, we agree
with Appellants that Linville does not disclose nor suggest an upstream
device transmitting above a predetermined threshold level as required by
claim 15. With respect to claim 13, which depends upon claim 5, as noted
supra, we agree with the Appellants that an upstream device transmitting
above a guaranteed service rate as required by claim 5 and a status threshold
for a queue buffer disclosed in McAlpine are not equivalent. Further, the
Examiner has not found that the additional teachings of Linville teach or
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suggest an upstream device transmitting above a predetermined threshold
level.
Therefore, we find that the combined teachings of Clarke, McAlpine,
and Linville do not disclose all the limitations of independent claims 1, 5,
and 15. Thus, we find error in the Examiner’s rejection of claims 1-3, 13,
15-18, 21, and 22 under 35 U.S.C. § 103(a) as unpatentable over Clarke in
view of McAlpine and Linville, and we will not sustain the rejection.

Claim 4
Appellants argue that claim 4 is patentable over the cited prior art
because the claim depends from claim 3 and because Joung does not cure the
deficiencies asserted with respect to the Clarke, McAlpine, and Linville
references (App. Br. 21).
As noted supra, we find that the combination of Clarke, McAlpine,
and Linville do not teach all the features of claim 3. The Examiner has not
found that the teachings of Joung cure the above noted deficiencies in the
rejection of claim 3 over the combination of Clarke, McAlpine, and Linville.
We therefore reverse the Examiner’s rejection of claim 4 under 35 U.S.C. §
103, for the same reasons expressed with respect to parent claim 3, supra.

Claim 14
Appellants argue that claim 14 is patentable over the cited prior art
because the claim depends from claim 13 and because Abdelilah does not
cure the deficiencies asserted with respect to the Clarke, McAlpine, and
Linville references (App. Br. 21).
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As noted supra, we find that the combination of Clarke, McAlpine,
and Linville do not teach all the features of claim 13. The Examiner has not
found that the teachings of Abdelilah cure the above noted deficiencies in
the rejection of claim 13 over the combination of Clarke, McAlpine, and
Linville. We therefore reverse the Examiner’s rejection of claim 14 under 35
U.S.C. § 103, for the same reasons expressed with respect to parent claim
13, supra.
Claim 29
Appellants argue that claim 29 is patentable over the cited prior art
because the claim depends from claim 28 and because Abdelilah does not
cure the deficiencies asserted with respect to the Clarke and Linville
references (App. Br. 21).
As noted supra, we find that the combination of Clarke and Linville
do not teach all the features of claim 28. The Examiner has not found that
the teachings of Abdelilah cure the above noted deficiencies in the rejection
of claim 28 over the combination of Clarke and Linville. We therefore
reverse the Examiner’s rejection of claim 29 under 35 U.S.C. § 103, for the
same reasons expressed with respect to parent claim 28, supra.

CONCLUSIONS OF LAW
Appellants have shown that the Examiner erred in finding that Clarke
in combination with McAlpine teaches transmitting flow control messages to
one or more upstream nodes that are transmitting above a guaranteed service
rate.
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Appellants have shown that the Examiner erred in finding that Clarke
in combination with Linville teaches sending a flow control message to at
least one upstream device that is transmitting above a predetermined level.

ORDER
The Examiner’s rejection of claims 1-10, 13-18, and 21-29 is
reversed.
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REVERSED

ELD

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