Prosecution Insights
Last updated: April 19, 2026
Application No. 18/492,975

Extended shortest path first computation for anycast prefix segments

Non-Final OA §103
Filed
Oct 24, 2023
Examiner
MIAN, OMER S
Art Unit
2461
Tech Center
2400 — Computer Networks
Assignee
Ciena Corporation
OA Round
1 (Non-Final)
70%
Grant Probability
Favorable
1-2
OA Rounds
3y 1m
To Grant
99%
With Interview

Examiner Intelligence

Grants 70% — above average
70%
Career Allow Rate
531 granted / 756 resolved
+12.2% vs TC avg
Strong +54% interview lift
Without
With
+53.6%
Interview Lift
resolved cases with interview
Typical timeline
3y 1m
Avg Prosecution
31 currently pending
Career history
787
Total Applications
across all art units

Statute-Specific Performance

§101
4.8%
-35.2% vs TC avg
§103
53.4%
+13.4% vs TC avg
§102
16.7%
-23.3% vs TC avg
§112
18.7%
-21.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 756 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claim(s) 1-3, 5, 7-10, 12, 14-16, 18, 20, is/are rejected under 35 U.S.C. 103 as being unpatentable over LU et al (US 2022/0337514) in view of SINGH et al (2017/0288948) Regarding claim 1, 8, 15, LU et al (US 2022/0337514) discloses a router comprising circuitry configured to: receive an Interior Gateway Protocol (IGP) update with anycast group information therein (LU: ¶115, ¶232, ¶233, ¶241, ¶247, ¶169, Fig. 11, ¶369, ¶360, the first SFF (router) receives an indication of failure by receiving an update to anycast group information (in the sub-TLV field) including the change in the destination address field which includes the proxy SID information), create or update a record for an anycast group with the anycast group information (LU: ¶232-242, a link between the first SFF and the first SF network element is faulty is detected and the updates are performed based on the anycast group information in the sub-TLV field), compute a route for the anycast group based on a failure detection associated with the anycast group information, and install the computed route (LU: ¶231, ¶236, ¶245, the SL and segment list is updated according to the updated route and destination and the route based on the proxy SID and the failure detection is installed/programmed and activated). LU remains silent regarding the computing based on a preferred metric in response to failure detection. However, SINGH et al discloses the computing based on a preferred metric in response to failure detection (SINGH: ¶7, ¶32, a preferred IGP metric is used to determine the alternative path/backup path with common anycast group in response to a failure of path) A person of ordinary skill in the art working with the invention of LU would have been motivated to use the teachings of SING as it avoids traffic black-holing in a multi-homed Ethernet virtual private network (EVPN) data center interconnect (DCI) between multiple data centers networks due to a failure of the designated forwarded (DF) in an active-standby multi-homing configuration (¶6) Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify invention of LU with teachings of SING in order to improve failure handling. Regarding claim 2, 9,16, LU modified by SINGH discloses the router of claim 1, wherein the preferred metric is specifically defined in terms of destination address information (LU: ¶169, sub-TLV includes the backup path indication in terms of destination address;). LU modified by SINGH remains silent regarding, however, SINGH in an embodiment disclose regarding a destination address information being part of the anycast group information (SINGH: ¶29, the destination address is in the anycast group address) A person of ordinary skill in the art working with the invention of LU modified by SINGH would have been motivated to use the teachings of SINGH as it provides faster, more deterministic anycast resolution by enabling traffic forwarding to the topologically closest anycast node. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify invention of LU modified by SINGH with teachings of SINGH in order to improved anycast routing. Regarding claim 3, 10, LU modified by SINGH discloses router of claim 2, wherein the preferred metric is specifically defined in the anycast group information in a sub-Type-Length-Value (TLV) (LU: ¶169, sub-TLV includes the backup path indication in terms of destination address; SINGH: ¶29, the destination address is in the anycast group address). Regarding claim 7, 14, 20 LU modified by SINGH discloses router of claim 1, wherein the anycast group information includes one of (1) border nodes sharing a same anycast prefix segment, and (2) planes of a plurality of nodes sharing a same anycast prefix segment (LU: ¶164, ¶169, ¶189-191, IPv6 prefix for an anycast group). Claim(s) 4, 6, 11, 13, 17, 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over LU modified by SINGH as applied to claim 1/8/15 above, further in view of BERZIN et al (US 2021/0297891) Regarding claim 4, 11, 17, LU modified by SINGH discloses router of claim 1/8/15, wherein the preferred metric a metric based on which path is computer (LU: ¶245, the SL list is updated according to the updated route and destination and the route based on the proxy SID and the failure detection is installed) LU modified by SINGH remains silent regarding the preferred metric being another metric besides an IGP metric. However, BERZIN et al (US 2021/0297891) discloses the preferred metric being another metric besides an IGP metric (BERZIN: ¶66, delay and TE metrics in IGP message which are other than an IGP metric). A person of ordinary skill in the art working with the invention of LU modified by SINGH would have been motivated to use the teachings of BERZIN as it provides computational liberty to the computational algorithm. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify invention of LU modified by SINGH with teachings of BERZIN in order to improve failure handling by adding flexibility of metrics. Regarding claim 6, 13, 19, LU modified by SINGH discloses router of claim 1/8/15, wherein the preferred metric is specified in the IGP update, the metric being for the route for the anycast group (SINGH: ¶35-37, IGP update messages with the metric and is for anycast group). LU modified by SINGH remains silent regarding, however, BERZIN discloses the metric being a delay and wherein the circuitry is further configured to perform a delay measurement to obtain delay metrics (BERZIN: ¶47, ¶66, the metric includes latency/delay and it is measure for the route). A person of ordinary skill in the art working with the invention of LU modified by SINGH would have been motivated to use the teachings of BERZIN as it provides computational liberty to the computational algorithm. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify invention of LU modified by SINGH with teachings of BERZIN in order to improve failure handling by adding flexibility of metrics. Claim(s) 5, 12, 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over LU modified by SINGH as applied to claim 1/8/15 above, further in view of XU et al (US 2023/0216775) Regarding claim 5, 12, 18, LU modified by SINGH discloses router of claim 1, wherein the IGP update is via an a sub-TLV therein specifying the preferred metric (LU: ¶169, sub-TLV includes the backup path indication in terms of destination address; SINGH: ¶29, the destination address is in the anycast group address). LU modified by SINGH remains silent regarding the sub-TLV being of an Extended IP Reachability Type-Length-Value (TLV). However, XU et al (US 2023/0216775) discloses the sub-TLV being of an Extended IP Reachability Type-Length-Value (TLV) (XU: Fig. 8, ¶127-128, the sub-TLV being in an Extended IP reachability TLV). A person of ordinary skill in the art working with the invention of LU modified by SINGH would have been motivated to use the teachings of XU as it allows for larger metric values compared to the narrow metric's limit of 63, which is essential for accurate path selection in large service provider networks. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify invention of LU modified by SINGH with teachings of XU in order to allow expansion of the network without compromising manageability and route filtering. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Document U discloses details of SID reachability, SR endpoint behaviors, and SR policy headend behaviors. It indicates the SRv6 counters implementation in nodes and security considerations, and IGP and control plane details. See the attached document for details. Document V discloses AOSPF (Anycast Extensions to OSPFv3) routing protocol extending OSPFv3 to support anycast, after analyzing the similarity and difference between anycast and unicast. Also, implementation of AOSPF and its testing in an IPv6 test bed. Further, the performance analysis shows the overhead of AOSPF is low. See the attached document for details. Any inquiry concerning this communication or earlier communications from the examiner should be directed to OMER S MIAN whose telephone number is (571)270-7524. The examiner can normally be reached M,T,W,Th: 10a-7p, Fri, 9a-12p. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Huy D Vu can be reached at 571-272-3155. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. OMER S. MIAN Primary Examiner Art Unit 2461 /OMER S MIAN/ Primary Examiner, Art Unit 2461
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Prosecution Timeline

Oct 24, 2023
Application Filed
Jan 22, 2026
Non-Final Rejection — §103 (current)

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Prosecution Projections

1-2
Expected OA Rounds
70%
Grant Probability
99%
With Interview (+53.6%)
3y 1m
Median Time to Grant
Low
PTA Risk
Based on 756 resolved cases by this examiner. Grant probability derived from career allow rate.

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