CenturyLink Intellectual Property LLC

Patent Trials and Appeals Board

Jun 2, 2021

2020000794 (P.T.A.B. Jun. 2, 2021)

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.
15/135,239 04/21/2016 Donald J. Smith 1375-US-C1 9806
83809 7590 06/02/2021
CenturyLink Intellectual Property LLC
Patent Docketing
1025 Eldorado Blvd.
Broomfield, CO 80021
EXAMINER
WILCOX, JAMES J
ART UNIT PAPER NUMBER
2439
NOTIFICATION DATE DELIVERY MODE
06/02/2021 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):
patent.docketing@centurylink.com
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte DONALD J. SMITH, MICHAEL GLENN,
JOHN A. SCHIEL and CHRISTOPHER L. GARNER
___________

Appeal 2020-000794
Application 15/135,239
Technology Center 2400

____________

Before CARL W. WHITEHEAD JR., MICHAEL J. STRAUSS and
IRVIN E. BRANCH, Administrative Patent Judges.

WHITEHEAD JR., Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE1
Appellant2 is appealing the final rejection of claims 1–16 and 18–21
under 35 U.S.C. § 134(a). See Appeal Brief 3. Claims 1, 2 and 18 are

1 Rather than reiterate Appellant’s arguments and the Examiner’s
determinations, we refer to the Appeal Brief (filed June 7, 2019), the Reply
Brief (filed November 7, 2019), the Final Action (mailed March 7, 2019)
and the Answer (mailed September 19, 2019), for the respective details.

2 “Appellant” to refer to “applicant” as defined in 37 C.F.R. § 1.42(a).
(“The word ‘applicant’ when used in this title refers to the inventor or all of
the joint inventors, or to the person applying for a patent as provided in
§§ 1.43, 1.45, or 1.46.”). Appellant identifies CenturyLink Intellectual
Appeal 2020-000794
Application 15/135,239
2

independent and claim 17 is cancelled. Appeal Brief 3. We have
jurisdiction under 35 U.S.C. § 6(b).
We reverse.
Introduction
According to Appellant, the claimed subject matter is “generally
directed to traffic scrubbing and load balancing to anycasted servers.”
Appeal Brief 3.

Representative Claim3 (disputed limitations emphasized)
1. A method, comprising:
receiving, at an edge router, network traffic addressed to a first anycast
address assigned to a plurality of anycasted servers, the plurality of
anycasted servers assigned to the first anycast address comprising
one or more anycasted servers and a subset of servers of the
plurality of servers assigned to a third anycast address;
forwarding, from the edge router, the network traffic addressed to the
first anycast address to a second anycast address assigned to each
of one or more data scrubbing appliances in at least one data
scrubbing appliance network;
receiving, with at least one data scrubbing appliance, the network
traffic from the edge router;
filtering, with the at least one data scrubbing appliance, undesirable
traffic from the network traffic;

Property LLC as the real party in interest. Appeal Brief 3.

3 Appellant states, “Claims 2 and 18 recite similar features to claim 1.
Therefore, Appellants respectfully submit that the arguments presented
above with respect to claim 1 are similarly applicable to claims 2 and 18.”
Appeal Brief 25. Accordingly, we select independent claim 1 as the
representative claim. See 37 C.F.R. § 41.37(c)(1)(iv).
Appeal 2020-000794
Application 15/135,239
3

transmitting the filtered network traffic from the at least one data
scrubbing appliance to at least one of the plurality of anycasted
servers assigned to the first anycast address or the subset of
servers of the plurality of servers assigned to the third anycast
address; and
load balancing the filtered network traffic to the plurality of anycasted
servers, wherein load balancing the filtered network traffic to the
one or more servers comprises prioritizing routing at least some of
the filtered network traffic to the subset of the plurality of servers
assigned to the third anycast address rather than routing at least
some of the filtered traffic to a subset of the plurality of servers
assigned only to the first anycast address.
Appeal Brief 27 (Claims Appendix).

References
Name4 Reference Date
B. Woodcock “Best Practices in IPv4 Anycast
Routing” Version 0.9 Packet
Clearing House
August 2002
R.
Louwersheimer
“Implementing Anycast in IPv4
Networks,” International
Network Services
June 2004
Cisco “Cisco DDOS Protection
Solution - Delivering “Clean
Pipes” Capabilities For Service
Providers and Their Customers”
June 2005
Jin CN 101924764 A December 22, 2010
Corelan Team “Juniper ScreenOS: Default
Route Manipulations and
Redistributions”
March 3, 2011
Microsoft “What is Unicast IPv4 Routing?” May 3, 2011
Rezaki US 2009/0067427 A1 March 12, 2009
Lee US 2011/0134769 A1 June 9, 2011

4 All reference citations are to the first named inventor only.

Appeal 2020-000794
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4

Rejections on Appeal
Claims 1–3, 7–10, 13–16 and 18–20 stand rejected under 35 U.S.C. §
103(a) as being unpatentable over Cisco, Woodcock, Jin and Rezaki. Final
Action 5–27.
Claims 4 and 5 stand rejected under 35 U.S.C. § 103(a) as being
unpatentable over Cisco, Woodcock, Jin, Rezaki and Corelan Team. Final
Action 28–29.
Claims 6 and 11 stand rejected under 35 U.S.C. § 103(a) as being
unpatentable over Cisco, Woodcock, Jin, Rezaki and Louwersheimer. Final
Action 30–32.
Claim 12 stands rejected under 35 U.S.C. § 103(a) as being
unpatentable over Cisco, Woodcock, Jin, Rezaki, Louwersheimer and
Microsoft. Final Action 32–33.
Claim 21 stands rejected under 35 U.S.C. § 103(a) as being
unpatentable over Cisco, Woodcock, Jin, Rezaki and Lee. Final Action 33–
35.

ANALYSIS
Appellant contends, “Cisco and Rezaki are silent regarding assigning
a third anycast address to a subset of servers of a plurality of servers already
assigned a first anycast address, as recited in the
claims.” Appeal Brief 20. The Examiner finds that Cisco discloses, “the
subset of servers of the plurality of servers assigned to the third anycast
address.” Final Action 6 (citing “Cisco, Page 14 describes that server farms
can be used with the topology; Page 6 describe assigning a unique IP
anycast addresses”). Appellant argues that “Cisco merely describes
anycasting as a technique to be implemented separately from their Cisco
Appeal 2020-000794
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5

DDoS [distributed-denial-of-service] Protection Solution.”5 Appeal Brief 21
(citing Cisco Figure 6).
The Examiner further finds:
Rezaki discloses wherein the load balancing the filtered
network traffic to the one or more servers comprises prioritizing
routing at least some of the filtered network traffic to the subset
of the plurality of servers assigned to the third anycast address
rather than routing at least some of the filtered traffic to a subset
of the plurality of servers assigned only to the first anycast
address (Rezaki, [0017] & [0037]−[0039] describe balancing
the load from the filtered network traffic to the one or more
servers comprises prioritizing routing by using routing tables at
least some of the filtered network traffic to the subset of servers
assigned to the third anycast address rather than routing at least
some of the filtered traffic to a subset of the plurality of servers
assigned only to the first anycast address).
Final Action 9.
Appellant argues:
Rezaki merely teaches that different groups of servers are
assigned different anycast addresses. Rezaki is silent regarding
subsets of servers within any of the groups of servers (e.g.,
groups of DNS [domain name system] servers (GDNS), groups
of SIP [session initiation protocol] servers (GSIP), or groups of
NTP [network time protocol] servers (GNTP)), let alone subsets
of servers within groups of servers already assigned a first
anycast address, further being assigned an additional anycast
address (e.g., “third anycast address”), as recited in the claims.
Appeal Brief 22.
The Examiner finds that Woodcock discloses, “[T]he plurality of
anycasted servers assigned to the first anycast address comprising one or
more anycasted servers and a subset of servers of the plurality of servers

5 “A DDoS attack is an attack on the end host system or the network
infrastructure that disrupts service to the user.” Cisco 1.
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assigned to the third anycast address.” Answer 6; see Woodcock 3, 12−16.
The Examiner determines that, “Woodcock describes building [an] anycast
server cluster, a round robin load balancing scheme and anycasting three
server instances with a router and a routing table where each server instance
has its own anycast address (therefore there is three anycast addresses).”
Answer 6. Appellant contends, “Woodcock merely teaches round-robin load
balancing to multiple server instances (e.g., Server Instances A-C).
Woodcock teaches that the server instances may share an anycasted
address (e.g., 10.0.0.1), however fails to teach or suggest a subset of the
servers being assigned to a separate anycasted address.” Reply Brief 5.
We find Appellant’s arguments persuasive of Examiner error. We
agree with Appellant’s conclusion, upon preponderance of cited references,
that “no combination of Cisco, Woodcock, Jin, and Rezaki teaches or
suggests a subset of server assigned a third anycast address, to which traffic
may be prioritized” as required by claim 1. Reply Brief 5.
Accordingly, we reverse the Examiner’s obviousness rejection of
claim 1, as well as, independent claims 2, 18, commensurate in scope, and
dependent claims 3–16 and 19–21.

CONCLUSION
Claims
Rejected
35 U.S.C.
§
Reference(s)/Basis Affirmed Reversed
1–3, 7–10,
13–16, 18–20
103 Cisco, Woodcock,
Jin, Rezaki
1–3, 7–10,
13–16, 18–20
4, 5 103 Cisco, Woodcock,
Jin, Rezaki,
Corelan Team
4, 5
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Application 15/135,239
7

Claims
Rejected
35 U.S.C.
§
Reference(s)/Basis Affirmed Reversed
6, 11 103 Cisco, Woodcock,
Jin, Rezaki,
Louwersheimer
6, 11
12 103 Cisco, Woodcock,
Jin, Rezaki,
Louwersheimer,
Microsoft
12
21 103 Cisco, Woodcock,
Jin, Rezaki, Lee
21
Overall
Outcome
1–16, 18–21

REVERSED