Prosecution Insights
Last updated: April 19, 2026
Application No. 18/606,422

Optimized Traffic Switchover Across Redundant Switch Cards

Non-Final OA §103
Filed
Mar 15, 2024
Examiner
WONG, WARNER
Art Unit
2469
Tech Center
2400 — Computer Networks
Assignee
Arista Networks, Inc.
OA Round
1 (Non-Final)
89%
Grant Probability
Favorable
1-2
OA Rounds
2y 10m
To Grant
96%
With Interview

Examiner Intelligence

Grants 89% — above average
89%
Career Allow Rate
936 granted / 1048 resolved
+31.3% vs TC avg
Moderate +6% lift
Without
With
+6.3%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
41 currently pending
Career history
1089
Total Applications
across all art units

Statute-Specific Performance

§101
6.1%
-33.9% vs TC avg
§103
56.3%
+16.3% vs TC avg
§102
24.7%
-15.3% vs TC avg
§112
2.8%
-37.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1048 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 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. Claims 1-3, 8-9, 12-14 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Moller (US 2003/0117949) in view of Kumar (US 2005/0114657). Regarding claims 1 and 13, Moller describes a method performed by a network device/network device comprising a primary switch card, a secondary switch card, and one or more line cards that are communicatively coupled with the primary and secondary switch cards (fig. 1, switch system with switch fabric 12 (primary switch card), switch fabric 14 (secondary switch card (line cards 20,22,24,26), comprising: initializing a global object to a first value associated with the primary switch card (para. 34, control line value (global object) first set to low (first value) before switchover); for each front panel port of the network device that is associated with the line card: programming a rule that includes a first match criterion matching network packets received on the front panel port (fig. 2 & para. 24, software program-implemented method where each of line cards 20,22,24,26 is set (rule) to receive instructions from controller 30 to which switch fabric to use & when allowed (first match criterion) to forward stored data received from ports of the line (port) card, para. 2 & 21), a second match criterion matching network packets which are received while the global object is set to the first value (para. 34, condition (second match criterion) when control line value (global object) first set to low (first value) before switchover), and a first action that causes network packets which match the first match criterion and the second match criterion to be redirected to the primary switch card (para. 24, when allowed to forward data received from line card’s port (first match criterion) & when control line value (global object) is low (second match criterion) (para. 34), each line card will direct/forward data packets to the [first] switch fabric, fig. 1 #12); programming a second rule that includes the first match criterion (fig. 2 & para. 24, software program-implemented method where each of line cards 20,22,24,26 is set (second rule which comprises the first rule) to receive instruction from controller 30 to which switch fabric to use & when allowed (first match criterion) to forward stored data received from ports of the line (port) card, para. 2 & 21), a third match criterion matching network packets which are received while the global object is set to a second value associated with the secondary switch card (para. 34, condition (third match criterion) when control line value (global object) set to high (second value) during switchover), and a second action that causes network packets which match the first match criterion and the third match criterion to be redirected to the secondary switch card; and enabling the first and second rules and upon occurrence of a failure at the primary switch card, causing the global object to change from the first value to the second value (para. 24, when allowed to forward data received from line card’s port (second match criterion comprising first match criterion) & when control line value (global object) is high (third match criterion) (para. 34), each line card will direct/forward data packets to the [second] switch fabric, fig. 1 #14, in event of failure/fault condition fig. 2 step 60 & para. 25). Moller fails to further explicitly describe: for each line card, setting the first & second ternary content-addressable memory (TCAM) rules into a TCAM of the line card. Kumar also describes switch system with switch fabric 110 & switch line cards 400 (fig. 1 & 4 + para. 67-68), further describing: for each line card, setting the first & second ternary content-addressable memory (TCAM) rules into a TCAM of the line card (para. 4-6, line/port cards use TCAMs with rules & fields for ACL-based packet filtering). It would have been obvious to one with ordinary skill in the art before the effective date of the claimed invention to specify that the switch line card of Moller to use TCAM with rules as in Kumar. The motivation for combining the teachings is that this achieve enhanced lookup performance in providing line rate performance for ACL-based packet filtering (Kumar, para. 5-6). Regarding claims 2 and 14, Moller and Kumar combined describe: wherein the global object is a variable that is managed by an operating system (OS) running on a central processing unit (CPU) of the network device (Moller, para. 24 or 38, software-implemented method in a computer (with CPU & OS)). Regarding claim 3, Moller and Kumar combined describe: wherein the OS changes the global object from the first value to the second value in response to detecting the failure at the primary switch card (Moller para. 24, software implemented method, when control line value (global object) goes from low (first value) to high (second value) (para. 34), in event of failure/fault condition fig. 2 step 60 & para. 25). Regarding claims 8 and 17, Moller and Kumar combined describe: wherein the global object corresponds to one or more hardware signals generated by one or more components of the network device (Moller para. 34, control line value (global object) is a hardware signal that goes from low (first value) to high (second value)). Regarding claim 9, Moller and Kumar combined describe: wherein the failure is a physical removal of the primary switch card from the network device (Moller para. 34, control line value (global object) is a hardware signal that goes from low (first value) to high (second value), in event of failure/fault of primary switch 12 (primary), requiring switchover to switch 14, fig. 1-2 step 60 & para. 25). Regarding claim 12, Moller and Kumar combined already describe programming TCAM rules into the TCAM of the line card from claim 1. Moller further describes: a third rule that includes the first match criterion, a fourth match criterion matching network packets that are received while the global object is set to a concatenation of hardware signals indicating that the primary and secondary switch cards are both installed in the network device, and a third action that causes matched network packets to be redirected to a predetermined one of the primary and secondary switch cards (Moller fig. 1 & para. 46, condition when both switch fabrics 12 & 14 are available, a match of packet’s fabric identifier and the value of the fabric identifier field will direct packet to the designated active fabric (of the 2 fabrics)). Claim 18 is a method claim which comprises limitation steps very similar to that of method claim 1 (reworded), with subset of all limitations since the “initializing the global object” limitation of claim 1 is being extracted to separate dependent claim 20. Hence, it is rejected under the same rationale. Regarding claim 19, Moller and Kumar combined already describe: programming TCAM rules into the TCAM of the line card from claim 1. Moller further describe: wherein the first and second rules are enabled by default (para. 21, each of line cards 20,22,24,26 is set ( [default] rules) to receive instructions from controller 30 to which switch fabric to use & when allowed (first match criterion) to forward stored data received from ports of the line (port) card). Claim 20 comprises the subset limitation of claim 1. Hence, it is rejected under the same rationale. Allowable Subject Matter Claim 4-7, 10-11 and 15-16 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. allowed Regarding claims 4 and 15, the prior art fails to further explicitly describe: wherein the variable is a virtual local area network (VLAN) class identifier (ID) that is maintained in a VLAN table of each line card and is associated with a common VLAN ID that is assigned to every front panel port of the network device. Kondrat (US 7,706,255) describing use of VLAN identifier for redundant switching (title & col. 11 lines 35-45), in combination with Moller and Kumar, fail to fulfill the above additional features as a whole obvious. Regarding claims 5 and 16, the prior art fails to further explicitly describe: wherein the variable is a source virtual path (SOURCE_VP) class ID that is maintained in a SOURCE_VP table of each line card and is associated with a common SOURCE_VP ID that is assigned to every front panel port of the network device. The closest prior art, Shukia (US 8,190,769) describing provisioning network device with source virtual resource (col. 7 lines 40-50), in combination with Moller and Kumar, fail to fulfill the above additional features as a whole obvious. Regarding claim 10, the prior art fails to further explicitly describe: wherein the first value is a concatenation of hardware signals indicating that the primary switch card is installed in the network device and the secondary switch card is not installed in the network device. Regarding claim 11, the prior art fails to further explicitly describe: wherein the second value is a concatenation of hardware signals indicating that the secondary switch card is installed in the network device and the primary switch card is not installed in the network device. For claims 10-11, the closest prior art, Oltman (US 2009/0154342) describing redundant switch fabric where switch modules 42a and/or 42b may be missing & resulting reduced switch fabric capacity (title & para. 43), in combination with Moller and Kumar, fail to fulfill the above additional features as a whole obvious. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: Sharma (US 215/0263884) describing fabric switchover (fig. 4A), Kloth (US 2002/0089926) describing packet switching switchover in redundant switch fabric 15 (fig. 1), Schauller (US 2003/0112746) - Detection Of Faults And Switching Of Fabrics In A Redundant-architecture Communication System (title), Shinohara (US 2007/0201426) switching device with switching boards for switchover (fig. 1 & abstract) and Ra (US 2006/0109782) describing redundancy control of duplex (2) switch boards (fig. 3). Any inquiry concerning this communication or earlier communications from the examiner should be directed to WARNER WONG whose telephone number is (571)272-8197. The examiner can normally be reached M-F 7am - 3:30pm. 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, Ian Moore can be reached at 571-272-3085. 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. WARNER WONG Primary Examiner Art Unit 2469 /WARNER WONG/Primary Examiner, Art Unit 2469
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Prosecution Timeline

Mar 15, 2024
Application Filed
Mar 13, 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

1-2
Expected OA Rounds
89%
Grant Probability
96%
With Interview (+6.3%)
2y 10m
Median Time to Grant
Low
PTA Risk
Based on 1048 resolved cases by this examiner. Grant probability derived from career allow rate.

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