Prosecution Insights
Last updated: April 19, 2026
Application No. 18/634,795

SOLUTION FOR ROUTING IN A PARTITIONED SUBNET BASED ON DYNAMIC LIVENESS MONITORING

Non-Final OA §103
Filed
Apr 12, 2024
Examiner
SHINGLES, KRISTIE D
Art Unit
2453
Tech Center
2400 — Computer Networks
Assignee
Cisco Technology Inc.
OA Round
1 (Non-Final)
82%
Grant Probability
Favorable
1-2
OA Rounds
3y 0m
To Grant
95%
With Interview

Examiner Intelligence

Grants 82% — above average
82%
Career Allow Rate
653 granted / 792 resolved
+24.4% vs TC avg
Moderate +13% lift
Without
With
+13.0%
Interview Lift
resolved cases with interview
Typical timeline
3y 0m
Avg Prosecution
29 currently pending
Career history
821
Total Applications
across all art units

Statute-Specific Performance

§101
6.4%
-33.6% vs TC avg
§103
37.7%
-2.3% vs TC avg
§102
45.2%
+5.2% vs TC avg
§112
3.8%
-36.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 792 resolved cases

Office Action

§103
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 . DETAILED ACTION Claims 1-20 are pending. Claim Rejections - 35 USC § 103 I. 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. II. CLAIMS 1-20 are rejected under 35 U.S.C. 103 as being unpatentable over SAWYER et al (US 2020/0267086) in view of DIKSHIT et al (US 2025/0158913). Per claim 1, SAWYER et al teach a method of routing packets in a partitioned subnet, the method comprising: advertising a first host using a first address prefix (Abstract, paras 0018, 0020, 0028, 0043—advertising a first site/server host by services using a first subnet, address and prefix); routing, within a fabric of the data center, traffic to the first host using a second address prefix for a host route of the first host within the fabric of the data center, wherein the second address prefix is a longer prefix than the first address prefix (paras 0020, 0028, 0032, 0037-39, 0079-81, 0093—routing traffic to the first site using second subnet, address and prefix with a larger prefix that previous advertised address); performing a first probe that detects whether the first host is linked to the first switch (paras 0022, 0029, 0060-67—distributing probes to detect links between the catchment devices at each site and routers); and updating a first table of the first switch based on a first result of the first probe (paras 0011-13, 0028-29, 0045-47, 0050-51, 0075-77, 0081-86, 0093-95—changing/modifying routing/traffic shifting table based on the detected probe data). SAWYER et al teach network devices of network peers (para 0026) and the claim limitations as applied above, yet fail to explicitly teach “advertising by a data center to peers of the data center”, “performing by a first switch of the data center” and “routing, within a fabric of the data center”. However, DIKSHIT et al teach peer participating device or peer switches (paras 0013-14, 0032, 0050), host and server with corresponding subnet and switch (paras 0017-18) and route advertisement from a border device within a fabric of an overlay network (Abstract, paras 0019-22). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed the invention to combine the teachings of SAWYER et al and DIKSHIT et al for the purpose of advertising, performing and routing by a data center to peers, by a switch and within a fabric of the data center; which are a well-known in the art being performed in multi-fabric overlay network distributed across multiple sites. Claims 11 and 20 contain limitations that are substantially equivalent to the limitations of claim 1, and are therefore rejected under same basis. Per claim 2, SAWYER et al and DIKSHIT et al teach the method of claim 1, DIKSHIT et al further teach the method further comprising: updating a first table by adding to the first table the second address prefix in association with a MAC address of the first host; triggering a gateway protocol for the host route of the first host to advertise the second address prefix for the host route of the first host within the fabric of the data center; and configuring a performance measurement session for the host route of the first host (paras 0013, 0031-33, 0049-50, 0066—MAC address, border gateway protocol and indicia that the host route is included in the route advertisement and stored in a data structure on the network device; SAWYER et al: paras 0022-24, 0028, 0066, 0074-79—border gateway protocol and second address subset and prefix, performing catchment measuring, performance parameters/characteristics tracking and measuring). Claim 12 contains limitations that are substantially equivalent to the limitations of claim 2, and are therefore rejected under same basis. Per claim 3, SAWYER et al and DIKSHIT et al teach the method of claim 1, DIKSHIT et al further teach the method wherein, the data center aggregates a plurality of host routes within the fabric of the data center into the first address prefix, wherein the plurality of host routes includes the host route of the first host to a single; and the plurality of host routes are de-aggregated from the first address prefix by redistributing the plurality of host routes using a gateway protocol that is triggered upon the host route of the first host or the second address prefix being added to or removed from the first table (paras 0015, 0019-23—routes for intra-fabric tunnels determined by using internal border gateway protocol while the routes are determined by using external border gateway protocol, access switches determine respective routes to the hosts, multi-path routing, learning host routes in addition to the prefix routes; SAWYER et al: paras 0022-24, 0028, 0066, 0074-79—border gateway protocol). Claim 13 contains limitations that are substantially equivalent to the limitations of claim 3, and are therefore rejected under same basis. Per claim 4, SAWYER et al and DIKSHIT et al teach the method of claim 3, wherein the gateway protocol is a border gateway protocol or an interior gateway protocol (SAWYER et al: paras 0003, 0028—border gateway protocol; DIKSHIT et al: paras 0015, 0032—border gateway protocol and internal border gateway protocol). Claim 14 contains limitations that are substantially equivalent to the limitations of claim 4, and are therefore rejected under same basis. Per claim 5, SAWYER et al and DIKSHIT et al teach the method of claim 1, DIKSHIT et al teach the method wherein the method is performed in a network layer that is a layer 3 of an open systems interconnection model (paras 0023, 0029, 0031, 0049—network layer reachability, layer-3 routing, layer-3 hops). Claim 15 contains limitations that are substantially equivalent to the limitations of claim 5, and are therefore rejected under same basis. Per claim 6, SAWYER et al and DIKSHIT et al teach the method of claim 1, DIKSHIT et al teach wherein, the first host is a virtual machine running on a first server that is linked to the first switch, and the data center includes a second server that is linked to a second switch (paras 0010, 0013, 0028-29, 0033, 0076—virtual devices, virtual addresses, distributed virtual switch associated with one or more virtual addresses). Claim 16 contains limitations that are substantially equivalent to the limitations of claim 6, and are therefore rejected under same basis. Per claim 7, SAWYER et al and DIKSHIT et al teach the method of claim 6, SAWYER et al teach the method furthering comprising: moving the first host from the first server to the second server; performing a second probe by the first switch that returns a second result indicating that the first host is not running on the first server; and removing the host route of the first host from the first table (paras 0051-53, 0064-65, 0095—route injectors modify records of DNS servers to produce and/or remove entries for addressing that is introduced and/or removed as a result of the first change, determining that the second probe was shifted to a site as a result of the change in addressing, shifting additional traffic to remove some traffic from the new site depending on the available resources of the new site; DIKSHIT et al: paras 0026, 0056—forwarding hardware can remove entries from the forwarding hardware). Claim 17 contains limitations that are substantially equivalent to the limitations of claim 7, and are therefore rejected under same basis. Per claim 8, SAWYER et al and DIKSHIT et al teach the method of claim 7, SAWYER et al further teaching the method furthering comprising: performing a third probe by the second switch that returns a third result indicating that the first host is running on the second server; and adding the host route of the first host to a second table, wherein the second table is associated with host routes of the second switch (paras 0022, 0029, 0060-67, 0076-77, 0079, 0095—distributing probes to detect links between the catchment devices at each site and routers, including addition hops, sites and entries into the table). Per claim 9, SAWYER et al and DIKSHIT et al teach the method of claim 1, DIKSHIT et al teach the method furthering comprising: performing a second probe by a second switch, the second probe returning a second result indicating that the first host is linked to the second switch; and adding the host route of the first host to a second table, wherein the second table is associated with host routes of the second switch, wherein the first host is a virtual machine that is dual-homed, such that the virtual machine is linked to the first switch and is linked to the second switch (paras 0010, 0012-13, 0028-29, 0033, 0037-40, 0076—virtual devices, virtual addresses, distributed virtual switch associated with one or more virtual addresses, programming the host route in the forwarding hardware from the forwarding data structures, and route updates). Claim 18 contains limitations that are substantially equivalent to the limitations of claim 9, and are therefore rejected under same basis. Per claim 10, SAWYER et al and DIKSHIT et al teach the method of claim 1, DIKSHIT et al teach the method wherein: the first address prefix is a /24 prefix; the second address prefix is a /32 prefix; the first table is an address resolution protocol table; the first switch is a top-of-rack switch; the first probe is a performance measurement liveness probe; and the first host is a virtual machine or a virtual network function (paras 0020, 0028-29, 0033, 0076—address prefix /24 and /32, virtual devices, virtual addresses; SAWYER et al: paras 0011, 0013, 0021, 0023-25, 0032, 0041, 0066, 0074-76, 0079—advertised address /24, performance characteristics and tracked parameters detected by probes, mappings stored in table to track shifts in traffic from a probe). Claim 19 contains limitations that are substantially equivalent to the limitations of claim 10, and are therefore rejected under same basis. Conclusion III. The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: US 2006/0020796, US 2003/0204619, USPN 8457635; USPN 8456987. IV. Any inquiry concerning this communication or earlier communications from the examiner should be directed to KRISTIE D SHINGLES whose telephone number is (571)272-3888. The examiner can normally be reached on Monday-Thursday 10am-7pm. 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, Kamal Divecha can be reached on 571-272-5863. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /KRISTIE D SHINGLES/ Primary Examiner, Art Unit 2453
Read full office action

Prosecution Timeline

Apr 12, 2024
Application Filed
Dec 27, 2025
Non-Final Rejection — §103 (current)

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Prosecution Projections

1-2
Expected OA Rounds
82%
Grant Probability
95%
With Interview (+13.0%)
3y 0m
Median Time to Grant
Low
PTA Risk
Based on 792 resolved cases by this examiner. Grant probability derived from career allow rate.

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