Barak Gafni et al.

Patent Trials and Appeals Board

May 22, 2020

2019001786 (P.T.A.B. May. 22, 2020)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
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APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
14/634,842 03/01/2015 Barak Gafni 1058-1164.1 5981
82253 7590 05/22/2020
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ISRAEL
EXAMINER
FAYED, RASHA K
ART UNIT PAPER NUMBER
2413
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05/22/2020 ELECTRONIC
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PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte BARAK GAFNI, BENNY KOREN,
DAVID MOZES, and LINOR NEHAB
____________

Appeal 2019-001786
Application 14/634,842
Technology Center 2400
____________

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 1–31, i.e., all pending claims. We have jurisdiction under
35 U.S.C. § 6(b).
We affirm in part.

1 We use the word “Appellant” to refer to “applicant” as defined in
37 C.F.R. § 1.42 (2017). Appellant identifies the real party in interest
as Mellanox Technologies Ltd. Appeal Br. 1.
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STATEMENT OF THE CASE
The Invention
According to the Specification, the invention concerns “routing and
forwarding of data packets in [computer] networks.” Spec. 1.2 The
Specification describes the increasing use of Multiprotocol Label Switching
(MPLS) “in large-scale data center (DC) networks.” Id. at 3. The
Specification explains that “[i]n this setting, conventional implementations
of MPLS lead to [Next Hop Label Forwarding Entry] NHLFE tables that
grow geometrically with network size, thus limiting network scalability.”
Id. at 9. To address that problem, the invention configures routers “to
forward MPLS packets without label swapping, so that the same label ID
may be maintained over the entire path (or a substantial segment of the path)
of a packet through the network.” Id. In addition, the invention configures a
router’s Incoming Label Map (ILM) and forwarding tables “so that multiple
records in the ILM, corresponding to multiple, different label IDs, can all
point to and thus share the same multi-path forwarding group.” Id. at 9–10.
Exemplary Claims
Independent claims 1 and 25 exemplify the claims at issue and read as
follows:
1. A method for communication, comprising:
configuring a router, having multiple interfaces
connected to a network, to forward data packets in the network

2 This decision uses the following abbreviations: “Spec.” for the
Specification, filed March 1, 2015; “Final Act.” for the Final Office Action,
mailed March 12, 2018; “Appeal Br.” for the Appeal Brief, filed July 26,
2018; “Ans.” for the Examiner’s Answer, mailed November 2, 2018; and
“Reply Br.” for the Reply Brief, filed December 26, 2018.
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in accordance with Multiprotocol Label Switching (MPLS)
labels appended to the data packets;
defining a group of two or more of the interfaces as a
multi-path routing group, and storing, in a forwarding table
within the router, a set of entries consisting of one respective
entry for each of the interfaces in the group;
storing, in an incoming label map (ILM) within the
router, multiple records, each record including a label ID and a
corresponding pointer to one or more entries in the forwarding
table, wherein the multiple records include a plurality of records
whose pointers point to the set of the entries in the forwarding
table that belong to the multi-path routing group; and
upon receiving in the router an incoming data packet
having a label ID corresponding to any given record in the
plurality, selecting, responsively to the given record and to the
set of the entries in the forwarding table to which the given
record points, one of the interfaces in the group, and forwarding
the incoming data packet through the one of the interfaces
without changing the label ID.
25. A method for communication, comprising:
configuring a router, having multiple interfaces
connected to a network, to forward data packets in the network
using Multiprotocol Label Switching (MPLS) labels appended
to the data packets;
defining a group of two or more of the interfaces as a
multi-path routing group, and storing, in a forwarding table
within the router, a set of entries consisting of one respective
entry for each of the interfaces in the group;
upon receiving incoming data packets in the router:
looking up in the router respective label IDs that
are to be associated with the data packets to be forwarded
from the router through the network; and
mapping the data packets to respective egress
interfaces of the router, such that at least first and second
data packets having different, respective first and second
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label IDs are mapped to the same multi-path routing
group; and
forwarding the data packets through the respective egress
interfaces to which the data packets are mapped.
Appeal Br. 19, 22 (Claims App.).
The Prior Art Supporting the Rejections on Appeal
As evidence of unpatentability under 35 U.S.C. § 103, the Examiner
relies on the following prior art:
The Rejections on Appeal
Claims 1–6 and 8–12 stand rejected under 35 U.S.C. § 103 as
unpatentable over Kini, Akiya, and Lin. Final Act. 2–15.
Claims 13–18 and 20–31 stand rejected under 35 U.S.C. § 103 as
unpatentable over Kini and Akiya. Final Act. 15–34.
Claim 19 stands rejected under 35 U.S.C. § 103 as unpatentable over
Kini, Akiya, and Shiota. Final Act. 34–35.
Claim 7 stands rejected under 35 U.S.C. § 103 as unpatentable over
Kini, Akiya, Lin, and Shiota. Final Act. 35–36.
ANALYSIS
We have reviewed the rejections in light of Appellant’s arguments
that the Examiner erred. For the reasons explained below, we disagree with
the Examiner’s conclusions concerning unpatentability under § 103 for
Shiota US 2001/0021189 A1 Sept. 13, 2001
Kini et al. (“Kini”) US 2012/0069745 A1 Mar. 22, 2012
Lin et al. (“Lin”) US 2014/0293786 A1 Oct. 2, 2014
Akiya et al. (“Akiya”) US 2015/0109907 A1 Apr. 23, 2015
(filed Dec. 18, 2013)
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claims 1–24. But we agree with the Examiner’s conclusion concerning
unpatentability under § 103 for claims 25–31. We provide the following
to address and emphasize specific findings and arguments.
The § 103 Rejections of 1–6, 8–18, and 20–24
INDEPENDENT CLAIMS 1 AND 13
As noted above, the § 103 rejection of claim 1 rests on Kini, Akiya,
and Lin, while the § 103 rejection of claim 13 rests on Kini and Akiya. See
Final Act. 2–7, 15–19. Appellant argues that the Examiner erred in rejecting
each claim because the references generally, and Kini in particular, do not
teach or suggest the following limitations:
“forwarding the incoming data packet through the one of the
interfaces without changing the label ID” (claim 1); and
“caus[ing] the switching logic to forward the incoming data
packet through the one of the interfaces without changing the
label ID” (claim 13).
Appeal Br. 6–7, 13; Reply Br. 1–2.
Specifically, Appellant asserts that Kini’s “forwarding always
involves a swap or pop operation, which changes the label ID of the packet.”
Appeal Br. 6–7 (citing Kini ¶¶ 29, 48); see id. at 13. According to
Appellant, Kini “relates to label popping, which is the removal of a label
without adding a replacement.” Id. at 7. Appellant argues that removing a
label without adding a replacement does not teach the claimed forwarding
“without changing the label ID.” Id.; see id. at 13.
The Examiner finds that Kini describes forwarding an incoming data
packet through an interface without changing the label ID. Final Act. 4–5
(citing Kini ¶¶ 48, 61–62, Fig. 9); see id. at 17–18. Specifically, the
Examiner explains that in Kini “only the entry corresponding to the egress
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[Label Switched Router] LSR needs to be updated” so the “next hop is
changed but not the packet’s label.” Ans. 7 (emphasis omitted). According
to the Examiner, “popping means removing the label not changing it as
claimed.” Id. (emphasis omitted).
Based on the record before us, we agree with Appellant that the
Examiner has not adequately explained how the cited portions of Kini
describe the disputed forwarding “without changing the label ID” limitations
in claims 1 and 13. Kini discloses establishing hierarchical LSPs (Label
Switched Paths) in an “MPLS (Multi-Protocol Label Switching) network for
multiple FECs (Forwarding Equivalence Classes) belonging to multiple end
stations respectively.” Kini ¶ 7. “The hierarchical LSP for each FEC
includes an egress LSR (Label Switched Router) LSP that is common for
each of the FECs and forms a path an egress LSR for the FECs and is used
when label switching packets in the MPLS network.” Id. After an
intermediate LSR receives a label-mapping message, the intermediate LSR
“install[s] a label and the IP address of the egress LSR” in its NHLFE (Next
Hop Label Forwarding Entry) structure and “create[s] an entry in [its] ILM
[Incoming Label Map] structures such that [it] can perform label swapping
(or a penultimate pop).” Id. ¶ 48.
Hence, Kini concerns label mapping by performing label swapping
and label popping. A swap action replaces a label. Kini ¶¶ 63, 69. A pop
action removes a label. Id. In the cited portions, Kini does not describe
forwarding data packets without changing the label ID. The Examiner does
not explain how Kini’s label swapping and label popping maintain a label ID
without changing it. Hence, we do not sustain the § 103 rejections of claims
1 and 13.
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DEPENDENT CLAIMS 2–6, 8–12, 14–18, AND 20–24
Claims 2–6 and 8–12 depend directly or indirectly from claim 1, and
claims 14–18 and 20–24 depend directly or indirectly from claim 13. For
the reasons discussed for claims 1 and 13, we do not sustain the § 103
rejections of claims 2–6, 8–12, 14–18, and 20–24.
The § 103 Rejections of Claims 7 and 19
Claim 7 depends indirectly from claim 1, and claim 19 depends
indirectly from claim 13. On this record, the Examiner has not shown how
the additionally cited Shiota reference overcomes the deficiency in Kini
discussed above for claims 1 and 13. Hence, we do not sustain the § 103
rejections of claims 7 and 19.
Because our determinations resolve the obviousness issues for
claims 1 and 13 and their respective dependent claims, we need not address
Appellant’s other arguments regarding Examiner error. See, e.g., Beloit
Corp. v. Valmet Oy, 742 F.2d 1421, 1423 (Fed. Cir. 1984) (explaining that
an administrative agency may render a decision based on “a single
dispositive issue”).
The § 103 Rejection of Claims 25–31
INDEPENDENT CLAIM 25
As noted above, the § 103 rejection of claim 25 rests on Kini and
Akiya. See Final Act. 27–30. Appellant argues that the Examiner erred in
rejecting claim 25 because Kini and Akiya do not teach or suggest the
following limitation in claim 25: “defining a group of two or more of the
interfaces as a multi-path routing group, and storing, in a forwarding table
within the router, a set of entries consisting of one respective entry for each
of the interfaces in the group.” See Appeal Br. 16.
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In particular, Appellant argues that “Kini does not teach or suggest
defining a group of two or more of the interfaces” but instead describes
“entries relat[ing] to a single interface.” Appeal Br. 16. According to
Appellant, Kini describes “multiple destinations (FECs) that share a single
path, not a group of multiple interfaces.” Id. Further, Appellant asserts that
Akiya “relates only to a single interface for each label.” Id.
For the reasons explained below, we agree with the Examiner’s
determination that Kini teaches or suggests the disputed limitation. See
Final Act. 27–29 (citing Kini ¶¶ 7, 9, 33, 48, 56, 67). The disputed
limitation requires “a group of two or more of the interfaces as a multi-path
routing group” and storing “entries consisting of one respective entry for
each of the interfaces in the group.”
Kini discloses that an LSR’s NHLFE structure may include
information about the “outgoing interface.” Kini ¶ 53. In particular, Kini
explains that in response to a label-mapping message an LSR may “install an
entry in [its] NHLFE that includes”: (1) “an outgoing label”; (2) “a swap
action (or a pop action if performing penultimate popping)”; (3) “the next-
hop”; (4) “the outgoing interface” for the outgoing label; and (5) “other data
handling information.” Id. ¶ 48. Kini also discloses different outgoing
labels for different LSRs associated with different outgoing interfaces, e.g.,
label 2 for LSR 120 communicating through interface-link 145 with LSR
140 and label 3 for LSR 130 communicating through interface-link 135 with
LSR 140. Id. ¶¶ 31, 48, Fig. 1. Thus, LSR 140 defines “a group of two
or more of the interfaces as a multi-path routing group” according to the
disputed limitation. Further, NHLFE structure 180 in LSR 140 stores
information associated with label 2 and label 3, and thus stores “entries
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consisting of one respective entry for each of the interfaces in the group”
according to the disputed limitation. Id. ¶¶ 48, 52–53, 58, 61–62, 66, 68,
Fig. 1. Hence, the Examiner correctly finds that Kini teaches or suggests the
disputed limitation.
Because Appellant’s arguments have not persuaded us that the
Examiner erred in rejecting claim 25 for obviousness based on Kini and
Akiya, we sustain the § 103 rejection of claim 25.
DEPENDENT CLAIMS 26–31
We also sustain the § 103 rejection of dependent claims 26–31
because Appellant does not argue patentability separately for them. See
Appeal Br. 15–17; Reply Br. 1–5; 37 C.F.R. § 41.37(c)(1)(iv).
CONCLUSION
We reverse the Examiner’s decision to reject claims 1–24.
We affirm the Examiner’s decision to reject claims 25–31.
In summary:
Claims
Rejected 35 U.S.C. § Basis Affirmed Reversed
1–6, 8–12 103 Kini, Akiya, Lin 1–6, 8–12
13–18, 20–31 103 Kini, Akiya 25–31 13–18, 20–24
19 103 Kini, Akiya, Shiota 19
7 103 Kini, Akiya, Lin, Shiota 7
Overall
Outcome 25–31 1–24
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TIME PERIOD FOR RESPONSE
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). See
37 C.F.R. § 41.50(f).
AFFIRMED IN PART