Ex Parte Pirbhai et al

Patent Trial and Appeal Board

Nov 20, 2014

12480456 (P.T.A.B. Nov. 20, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte SHAFIQ PIRBHAI, RON HABERMAN,
and MUSTAPHA AISSAOUI
____________

Appeal 2012-007632
Application 12/480,456
Technology Center 2400
____________

Before JOHN A. EVANS, NATHAN A. ENGELS, and
CHRISTA P. ZADO, Administrative Patent Judges.

ZADO, Administrative Patent Judge.

DECISION ON APPEAL
Appellants1 appeal under 35 U.S.C. § 134(a) from the Examiner’s
final rejection of claims 1–4, 7–15, and 18–22.2 We have jurisdiction under
35 U.S.C. § 6(b).
We AFFIRM.

1 Appellants identify as the real party in interest Alcatel-Lucent. App. Br. 1.
2 Appellants improperly request withdrawal of the rejection of claims 5, 6,
16, and 17. App. Br. 8. Claims 5, 6, 16, and 17 have been cancelled, and
were not pending as of the filing of this Appeal. See Applicant
Amendment 3, 7, 9 (Sept. 1, 2011); Final Act. 2; Advisory Act. 1–3
(Feb. 10, 2012); App. Br. 16, 19; Ans. 3–17. Accordingly, claims 5, 6, 16,
and 17 are not on appeal, and we do not address them in this Decision on
Appeal.
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STATEMENT OF THE CASE
Appellants’ invention generally relates to maintaining updated MAC
address to IP address associations in a network. Spec. ¶ 9. Representative
claim 1, reproduced below (some paragraphing added), recites:
1. A provider edge node for allowing a customer edge device
to access a Virtual Leased Line (VLL) service, the provider edge node
comprising:
a cache that stores an association between an Internet Protocol
(IP) address of the customer edge device and a Media Access Control
(MAC) address of the customer edge device;
a backup memory that maintains a copy of a last-known IP
address of the customer edge device;
a communication interface that transmits data packets to the
MAC address of the customer edge device; and
a processor that[:]
updates the cache upon receipt of an address update message
from the customer edge device, the address update message indicating
the IP address and the MAC address of the customer edge device,
removes the stored association from the cache in response to a
cache-clearing event, while maintaining the copy of the last-known IP
address in the backup memory, wherein the cache-clearing event
temporarily interrupts connectivity to the customer edge device,
at a time subsequent to removal of the stored association from
the cache, sends an address discovery message using the
communication interface, the address discovery message requesting
an updated MAC address corresponding to the last-known IP address
maintained in the backup memory, and
updates the cache to reflect the updated MAC address upon
receipt of an additional address update message from the customer
edge device, wherein the address update message and the additional
address update message are Neighbor Discovery Protocol
advertisements and the address discovery message is a Neighbor
Discovery Protocol solicitation.
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THE REJECTIONS
1. Claims 1 and 12 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over Chen et al. (hereinafter “Chen”) (US 6,987,743 B2; issued
Jan. 7, 2006), Estrada et al. (hereinafter “Estrada”) (US 2009/0119414 A1;
published May 7, 2009), and Takagaki et al. (hereinafter “Takagaki”) (US
2008/0008183 A1; Jan. 10, 2008). Ans. 4
2. Claims 2, 3, 13, and 14 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over Chen, Estrada, Takagaki, and Teng (US 2009/0003241
A1; published Jan. 1, 2009). Ans. 9.
3. Claims 4, 7, 8, 15, 18, and 19 stand rejected under 35 U.S.C.
§ 103(a) as unpatentable over Chen, Estrada, Takagaki, and Srinivasan (US
2009/0285089 A1; published Nov. 19, 2009). Ans. 11.
4. Claims 9, 10, 20, and 21 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over Chen, Estrada, Takagaki, and Haberman et al. (hereinafter
“Haberman”) (US 7,827,310 B1; issued Nov. 2, 2010). Ans. 14.
5. Claims 11 and 22 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over Chen, Estrada, Takagaki, and Balus et al. (hereinafter
“Balus”) (US 2008/0084891 A1; published Apr. 10, 2008). Ans. 7.
Rather than repeat all the arguments here, we refer to the Briefs and
the Answer for the respective positions of Appellants and the Examiner.
Only those arguments actually made by Appellants have been considered in
this decision. Arguments that Appellants did not make in the Briefs have
not been considered and are deemed to be waived. See 37 C.F.R.
§ 41.37(c)(1)(vii).

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ISSUE AND ANALYSIS
Appellants contend the Examiner has erred in rejecting claims 1–4, 7–
15, and 18–22. App. Br. 13. Based upon Appellants arguments, the issue
before us is whether the Examiner erred by finding the combination of Chen
and Estrada teach or suggest “removes the stored association from the cache
in response to a cache-clearing event, while maintaining the copy of the last-
known IP address in the backup memory,” as recited in representative
claim 1.
Chen relates to supporting seamless hand-off in a mobile
telecommunications network. Chen col. 1, ll. 14–15. The Examiner finds
Chen teaches or suggests “removes the stored association from the cache in
response to a cache-clearing event, while maintaining a copy of the last-
known IP address” by disclosing the broadcasting of an Address Resolution
Protocol (ARP) request after an ARP cache time out. Ans. 5, 18, 19, citing
Chen col. 1, ll. 49–62. According to the Examiner, a copy of the last-known
IP address is necessarily maintained in Chen because the last-known IP
address is used in the broadcast ARP request after a cache time-out. Ans. 5,
18, 19.
Appellants contend, however, that Chen cannot maintain the last-
known IP address because Chen does not explicitly disclose a “backup
memory” to maintain the last-known IP address. App. Br. 5–6. Appellants’
argument is not persuasive because Chen does not need to explicitly disclose
a “backup memory” in order to teach maintaining a last-known IP address.
As explained by the Examiner, the last-known IP address is necessarily
maintained in Chen in order to enable broadcast of an ARP request after a
cache time-out. We agree with the Examiner that in order to send an ARP
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request (which contains the destination IP address) after a cache timeout, the
destination IP address must be maintained in some memory, even if Chen
does not explicitly identify where that memory is. Accordingly, we
conclude the Examiner reasonably finds Chen discloses “removes the stored
association from the cache in response to a cache-clearing event, while
maintaining the copy of the last-known IP address.”
Rather than rely on an inherent disclosure of “backup memory” in
Chen to maintain the IP address, the Examiner relies upon the teaching in
Estrada of backing up an ARP cache in data storage. Ans. 5, 18–20. Estrada
provides that “it has been recognized that if the data contents of the router
102 ARP cache 304 could be copied or acquired before the cache was
flushed or emptied, such data could be used to identify each computer device
that is connected to router 102 to transmit data.” Estrada ¶ 29; see also
¶¶ 30, 32. Therefore, according to the Examiner, Estrada teaches backing up
an IP address in backup memory. Ans. 19–20.
Appellants contend, however, that Estrada teaches away from the
claimed invention because Estrada teaches storing MAC addresses. App.
Br. 6–7. Appellants’ argument appears to be that the purpose of the claimed
invention is to use the maintained copy of the IP address to rediscover the
associated MAC address, whereas Estrada stores the MAC address
associated with the IP address, so that there is no need to rediscover the
MAC address. 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). Here, Appellants have not provided
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persuasive evidence or arguments that Estrada teaches away from the
claimed invention.
In particular, Estrada teaches storing all contents of the ARP cache,
including IP addresses, in backup memory by taking a snapshot of all ARP
cache content prior to flushing the ARP cache. Estrada ¶¶ 30, 32.
[P]rocessor 202 would act to acquire a copy of all data in ARP
cache 304 at specified times, and then enter the copied data into
a storage device 306 . . . The periodicity of the cache data
acquisitions would be determined . . . to ensure that a snapshot
of the ARP cache data 304 was always taken before a particular
set of contents was flushed from the cache.
Id. ¶ 30 (emphasis added).
“Respective entries [of the ARP cache] include . . . target IP address
418.” Id. ¶ 32. Estrada teaches using the ARP cache snapshot to construct a
sender MAC addresses database (Id. ¶ 35), but this does not discourage use
of a target IP address to update a target MAC address. Estrada describes
various uses of a sender MAC address database (see, e.g., Estrada ¶¶ 37–40),
none of which discourages using the backed up target IP-address to update a
target MAC address of a target device in connection with communicating
packets to the target device.
As a result, we are unpersuaded that the Examiner incorrectly
determined the combination of Chen and Estrada teaches or suggests
“removes the stored association from the cache in response to a cache-
clearing event, while maintaining the copy of the last-known IP address in
the backup memory,” as recited in representative claim 1.
We therefore sustain the Examiner’s rejection of (1) independent
claim 1; (2) independent claim 12 not argued separately (App. Br. 5–7);
dependant claims 2, 3, 13, and 14 for which Appellants raise no new
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arguments (App. Br. 9); dependent claims 4, 7, 8, 15, 18, and 19 for which
Appellants raise no new arguments (App. Br. 10); dependent claims 9, 10,
20, and 21 for which Appellants raise no new arguments (App. Br. 11); and
dependent claims 11 and 22 for which Appellants raise no new arguments
(App. Br. 12).

DECISION
The Examiner’s decision rejecting claims 1–4, 7–15, and 18–22 is
AFFIRMED.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).

AFFIRMED

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