Prosecution Insights
Last updated: April 19, 2026
Application No. 18/168,145

MULTICAST DISTRIBUTION TREE SWITCHOVER IN HETEROGENEOUS PROVIDER EDGE ENVIRONMENTS

Non-Final OA §103
Filed
Feb 13, 2023
Examiner
HAILU, KIBROM T
Art Unit
2461
Tech Center
2400 — Computer Networks
Assignee
Cisco Technology Inc.
OA Round
3 (Non-Final)
80%
Grant Probability
Favorable
3-4
OA Rounds
2y 11m
To Grant
86%
With Interview

Examiner Intelligence

Grants 80% — above average
80%
Career Allow Rate
677 granted / 847 resolved
+21.9% vs TC avg
Moderate +6% lift
Without
With
+6.3%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
40 currently pending
Career history
887
Total Applications
across all art units

Statute-Specific Performance

§101
4.7%
-35.3% vs TC avg
§103
49.9%
+9.9% vs TC avg
§102
23.0%
-17.0% vs TC avg
§112
12.9%
-27.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 847 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 . Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on February 3, 2026 has been entered. Response to Arguments Applicant’s arguments with respect to claims 1-20 have been considered but are moot due to the new ground of rejection. 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. Claims 1-2, 7-9, and 14-16 are rejected under 35 U.S.C. 103 as being unpatentable over Chai (US 2017/0288890 A1) in view of Lai (US 2017/0230484 A1). Regarding claim 1, Chai discloses a method comprising: discovering by a first network router in a network of routers associated with a provider network a network address translation service available at one or more second network routers (paragraph [0015]; [0035]; [0083]-[0085]; and so on, illustrating finding network multicast group address for switching a default MDT to data MDT); and selecting the network address translation service at one of the one or more second network routers (paragraph [0024]; [0045]; [0113], describing the network multicast group address is selected from network multicast group addresses), the network address translation service allowing creation of a dynamic data Multicast Distribution Tree (MDT), wherein after creation of the dynamic data MDT, the first network router remains on a default while at least a number of the one or more second network routers receive data flows over a data MDT (paragraph [0014]-[0024]; [0026]-[0041]; [0045]-[0052]; [0086]-[0076]; [0078]-[0080]; [0084]-[0085]; [0089]-[0090]; [0101]; [0106]; [0108]-[0119]; [0122], explaining based on the network multicast group address, due to switching, the first PE router remains on default MDT while the other routers receive the dynamic data flows over a data MDT). Chai doesn’t disclose the network address translation service is available at the one or more second network routers according to configuration, capability, or policy that may differ among the one or more second network routers. Lai teaches the network address translation service is available at the one or more second network routers according to configuration, capability, or policy that may differ among the one or more second network routers (paragraph [0019]-[0020]; [0028]; [0035]; [0042]; [0048]; [0054]-[0056]; and so on). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to use the network address translation service is available at the one or more second network routers according to configuration, capability, or policy that may differ among the one or more second network routers as taught by Lai into Chai in order to reduce communication failure and improve rate. Regarding claims 8 and 15, the claims include features identical to subject matter mentioned in the rejection to claim 1. The claims are mere reformulation of claim 1 in order to define the corresponding a network device and a non-transitory computer-readable medium, and the rejection to claim 1 is applied hereto. Regarding claim 2, 9, and 16, Chai discloses wherein the discovering is based on a Protocol-Independent Multicast (PIM) flooding mechanism (paragraph [0016]; [0022]-[0024]; [0033]-[0034]; [0043]-[0048]; [0070]-[0071]; [0074]-[0075]; [0085]; and so on). Regarding claim 7 and 14, Chai discloses wherein the first network router is in a path of a third network router, the third network router receiving data flows over the data MDT (fig. 1). Claims 3, 10, and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Chai in view of Lai, and further in view of Kumar et al. (US 10,608,931 B1). Regarding claim 3, 10, and 17, as applied above, Chai discloses wherein the network translation service is discovered. However, Chai doesn’t disclose the discovery is in response to one or more probes initiated by the first network router. Kumar teaches the discovery is in response to one or more probes initiated by the first network router (col. 1, line 45-col. 2, line 29; col. 3, lines 29-50; col. 4, lines 48-67; col. 9, line 38-col. 10, line 21; col. 12, line 56-col. 13, line 33; and so on). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to use the discovery is in response to one or more probes initiated by the first network router as taught by Kumar into Chai in order to improve quality of service. Claims 4-5, 11-12, and 18-19 are rejected under 35 U.S.C. 103 as being unpatentable over Chai in view of Lai, and further in view of Dutta (US 2022/0060412 A1). Regarding claim 4-5, 11-12, and 18-19, as applied above Chai one or the one or more second network routers. However, Chai doesn’t disclose further comprising: sending a request to the one or the one or more second network routers selected to install multicast network access translation entries, and wherein the request is sent in a Protocol-Independent Multicast (PIM) join message. Dutta teaches further comprising: sending a request to the one or the one or more second network routers selected to install multicast network access translation entries, and wherein the request is sent in a Protocol-Independent Multicast (PIM) join message (paragraph [0063]-[0065]). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to use further comprising: sending a request to the one or the one or more second network routers selected to install multicast network access translation entries, and wherein the request is sent in a Protocol-Independent Multicast (PIM) join message as taught by Dutta into Chai in order to reduce interference and increase efficiency. Claims 6, 13, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Chai in view of Lai, and further in view of Liu et (US 2014/0241357 A1). Regarding claim 6, 13, and 20, Chai further discloses comprising: the first network router having a first component and a second component (figs. 4-5). Chai doesn’t disclose generating an entry at the first network router having a first component and a second component, the first component being an identification of the one of the one or more second network routers selected, the second component being a new group in Source-Specific Multicast (SSM) range to identify the entry. Liu teaches generating an entry at the first network router having a first component and a second component, the first component being an identification of the one of the one or more second network routers selected, the second component being a new group in Source-Specific Multicast (SSM) range to identify the entry (paragraph [0051]). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to use generating an entry at the first network router having a first component and a second component, the first component being an identification of the one of the one or more second network routers selected, the second component being a new group in Source-Specific Multicast (SSM) range to identify the entry as taught by Dutta into Chai in order to improve security. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to KIBROM T HAILU whose telephone number is (571)270-1209. The examiner can normally be reached M-F 8:00 AM to 5:30 PM. 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. /KIBROM T HAILU/Primary Examiner, Art Unit 2461
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Prosecution Timeline

Feb 13, 2023
Application Filed
Apr 24, 2025
Non-Final Rejection — §103
Jul 29, 2025
Response Filed
Jul 29, 2025
Applicant Interview (Telephonic)
Aug 01, 2025
Examiner Interview Summary
Oct 30, 2025
Final Rejection — §103
Feb 02, 2026
Applicant Interview (Telephonic)
Feb 03, 2026
Request for Continued Examination
Feb 05, 2026
Examiner Interview Summary
Feb 14, 2026
Response after Non-Final Action
Mar 18, 2026
Non-Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
80%
Grant Probability
86%
With Interview (+6.3%)
2y 11m
Median Time to Grant
High
PTA Risk
Based on 847 resolved cases by this examiner. Grant probability derived from career allow rate.

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