Ex Parte Natarajan

Board of Patent Appeals and Interferences

Jan 20, 2012

11023409 (B.P.A.I. Jan. 20, 2012)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte SRIKANTH NATARAJAN
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Appeal 2010-001856
Application 11/023,409
Technology Center 2400
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Before MARC S. HOFF, THOMAS S. HAHN, and
BRADLEY W. BAUMEISTER, Administrative Patent Judges.

BAUMEISTER, Administrative Patent Judge.

DECISION ON APPEAL

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SUMMARY
Appellant appeals under 35 U.S.C. § 134(a) from the Examiner’s
rejections of claims 1-10, 12-20, 22, and 23:
1. Claims 1, 2, 4-9, and 15-19 stand rejected under 35 U.S.C. § 103(a) as
obvious over Kanekar (US 6,751,191 B1; issued June 15, 2004) in
view of Critchfield (US 7,152,179 B1; issued Dec. 19, 2006);1
2. Claim 3 stands rejected under 35 U.S.C. § 103(a) as obvious over
Kanekar in view of Critchfield and Hrastar (US 6,272,150 B1; issued
Aug. 7, 2001); and
3. Claims 10, 12-14, 20, 22, and 23 stand rejected under 35 U.S.C.
§ 103(a) as obvious over Ma (US 6,856,591 B1; issued Feb. 15, 2005)
in view of Critchfield.
We reverse.

1 In the Final Rejection mailed October 30, 2008, the Examiner initially
rejected claims 15 and 16 as obvious over Ma in view of Critchfield (Final
Rej. 6-9) – not Kanekar in view of Critchfield (see Final Rej. 2-5). Based on
the Final Rejection, Appellant contends in the Appeal Brief that claims 15
and 16 are not rendered obvious by the combination of Ma and Critchfield
(App. Br. 10). In the Examiner’s Answer, though, the Examiner changes the
basis of the rejection of claims 15 and 16, dropping the rejection based upon
Ma and newly rejecting them as obvious over Kanekar and Critchfield (Ans.
3, 5-6, 8). In the ensuing Reply Brief, Appellant disputes that claims 15 and
16 are rendered obvious by the combination of Kanekar and Critchfield
(Reply Br. 3). Accordingly, we understand the parties to have agreed that
claims 15 and 16 stand rejected over the combination of Kanekar and
Critchfield.
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STATEMENT OF THE CASE
Independent claim 1 is illustrative of the subject matter on appeal:
1. Method for monitoring status of a Hot Standby Routing
Protocol group of routers, comprising:
for each network interface of each router in the group,
monitoring changes in a status of the network interface;
based on the monitored changes, determining a status of
the group.

FINDINGS OF FACT
The record supports the following Findings of Fact (FF) by a
preponderance of the evidence:
1. Kanekar teaches that:
Since the slave and the master share the same set of interfaces,
the slave may observe incoming and outgoing packets and
therefore obtains information to update its layer 2 and layer 3
tables. More particularly, prior to failure of the master, the
master monitors all traffic entering the switch during active
forwarding of packets while the slave monitors all traffic
entering the switch while the slave is in standby mode.
(Col. 14, ll. 17-24).
2. Ma teaches that “. . . the network devices periodically advertise state
information using various messages (HSRP messages)” (col. 13, ll. 8-10).
3. Ma teaches that:
The HSRP messages may include Hello messages, Coup
messages, and Resign messages. The Hello messages are sent
to indicate that a network device is running and is capable of
becoming the active or standby commander. Coup messages
are sent when a network device wishes to become the active
commander. Resign messages are sent when a network device
no longer wishes to be the active commander.
(Col. 13, ll. 14-21).
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4. Ma teaches that “[a] HSRP network device maintains or changes its
state based on receipt (or non-receipt) of HSRP messages from other HSRP
network devices” (col. 14, ll. 49-51).
5. A technical dictionary defines “polling” as: “3: A sequential
interrogation of devices for various purposes, such as avoiding contention,
determining operational status, or determining readiness to transmit or
receive data.” MARTIN WEIK, COMPUTER SCIENCE AND COMMUNICATIONS
DICTIONARY, VOLUME 2, 1298-1299 (2000).

ISSUES
I. Did the Examiner err in determining that Kanekar teaches the
limitation of: “for each network interface of each router in the group,
monitoring changes in a status of the network interface” as recited in claims
1 and 17?
II. Did the Examiner err in determining that Ma teaches the
limitation of: “polling determined router interfaces to determine a status and
Hot Standby Routing Protocol priority of each interface” as recited in claim
10?

CONTENTIONS AND ANALYSIS
I. Analysis of claims 1, 2, 4-9, and 15-19 under 35 U.S.C. § 103(a) as
obvious over Kanekar in view of Critchfield and claim 3 under 35 U.S.C.
§ 103(a) as obvious over Kanekar in view of Critchfield and Hrastar
Appellant argues, inter alia, that Kanekar does not teach the limitation
of: “for each network interface of each router in the group, monitoring
changes in a status of the network interface” as recited in claims 1 and 17
(App. Br. 11; Reply Br. 1-2). Appellant argues that Kanekar’s monitoring of
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network traffic does not read on the limitation of “monitoring changes in a
status of the network interface” because network traffic is not the same as
interface status (App. Br. 11; Reply Br. 2).
We are persuaded by Appellant’s arguments. In finding that Kanekar
teaches the limitation at issue, the Examiner relies on Kanekar’s master and
slave routers that monitor traffic entering the switch through a shared set of
interfaces (Ans. 10-11; FF 1). However, Kanekar does not teach monitoring
each network interface for each router in a group (nor does it teach
monitoring the traffic through each network interface), but instead teaches
monitoring the router itself (FF 1). At best, Kanekar determines the status of
a group of all interfaces associated with a given router only under certain
circumstances.
For these reasons, Appellant has persuaded us that the Examiner erred
in determining that Kanekar teaches the limitation of: “for each network
interface of each router in the group, monitoring changes in a status of the
network interface” as recited in claim 1. Therefore, we do not sustain the
Examiner’s rejection under 35 U.S.C. § 103(a) of independent claim 1, of
independent claim 15, which also recites “means for monitoring changes in a
status of each network interface of each router in the group,” or of
independent claim 17 that has the same limitation as claim 1. Accordingly,
we likewise do not sustain the rejection of claims 2 and 4-9, which depend
from claim 1, of claim 16, which depends from claim 15, or of claims 18 and
19, which depend from claim 17.
With respect to the obviousness rejection of claim 3 which depends
from claim 1, the Examiner does not allege that Hrastar teaches the claim 1
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language that is missing from Kanekar and Critchfield (Ans. 7-8, 13-15).
We, therefore, do not sustain the Examiner’s rejection of claim 3.

II. Analysis of claims 10, 12-14, 20, 22, and 23 under 35 U.S.C. § 103(a) as
obvious over Ma in view of Critchfield
Claim 10 includes the limitation of: “polling determined router
interfaces to determine a status and Hot Standby Routing Protocol priority of
each interface.” The Examiner reasons (Ans. 8-9, 18-19) that Ma discloses
the claim 10 limitation of “polling determined router interfaces to determine
a status” because Ma’s network device receives, or does not receive,
periodically sent HSRP messages from other network devices.
A.
Appellant argues (App. Br. 17), inter alia, that the sections of Ma
cited by the Examiner do not mention a router interface and, therefore, do
not teach the limitation at issue. We agree. Ma teaches that a network
device periodically sends HSPR messages (FF 2-4), and Ma teaches that the
HSPR Hello messages indicate that the network device is running (FF 3).
However, the cited sections of Ma only teach receiving information about
the router, but do not teach that the HSPR messages are related to the
claimed “determined router interfaces” (see FF 3). Therefore, Ma’s teaching
of receiving HSPR messages does not read on the limitation of: “polling
determined router interfaces to determine a status and Hot Standby Routing
Protocol priority of each interface,” as recited in claim 10 (emphasis added).
B.
Appellant also argues (Reply Br. 3; App. Br. 17) that the cited
sections of Ma do not suggest the claimed “polling determined router
interfaces . . . ” (emphasis added), but in contrast teach that the HSPR
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messages are unsolicited because the messages are expected at an interval in
accordance with an active timer.
Appellant’s arguments are persuasive. Ma teaches that a network
device periodically sends HSPR messages to other network devices (FF 2-4).
A technical dictionary indicates that the claim term “polling” includes “[a]
sequential interrogation of devices for various purposes, such as . . .
determining operational status . . . .” (FF 5). Considering this definition of
polling, we find that Ma’s teaching of network devices sending unsolicited
periodic messages does not read on the limitation of “polling determined
router interfaces . . . .” “Polling” requires the interrogation of the router
interface(s) such as a signal to the router interface and a response back with
information about the router interface.
Accordingly, we do not sustain the Examiner’s rejection of claim 10,
of claim 12, which recites “polling the identified interfaces for status
information”, of claim 20, which has the same limitation as claim 10, or of
claim 22, which has the same limitation as claim 12. We likewise do not
sustain the rejection of claims 13 and 14, which depend from claim 12, or of
claim 23, which depends from claim 22.

DECISION
The Examiner’s decision rejecting claims 1-10, 12-20, 22, and 23 is
reversed.

REVERSED

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