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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 23 March, 2026 has been entered.
Claims 1-4, 6-11, 13-18 and 20 are pending.
Claims 1, 8 and 15 are amended.
Response to Arguments
Regarding amended claim 1, Applicant argues that the prior art of record does not teach the amended limitations. Examiner finds the argument persuasive and a new ground of rejection is presented herewith.
Regarding the motivation to combine the prior art of record, Berzin-Yen-NPL, Applicant argues that “…the Office Action conflates two different "depth" concepts”. Examiner finds that Applicant’s argument itself provides the response in that the cited prior art of record are all in the same field of endeavor of depth concepts, i.e. analogous art. As such, Examiner reiterates that it is not an unreasonable networking computation to identify the shortest possible path that also meets certain constraints, such as a Service Level Agreement for example, as it would facilitate efficient engineering of network traffic. Based on such rationale, Examiner maintains that the combination of Berzin-Yen-NPL would be obvious to one of ordinary skill in the art and the combination is maintained.
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.
Claims 1-4, 6-11, 13-18 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Berzin et al. (US 20210297891), in view of Yen et al. (“Finding the first shortest paths in a time window network”, Elsevier, October 2002), in view of RFC 8476, dated December 2018, hereinafter NPL, further in view of Tantsura et al (US 11,038,791).
Regarding claim 1, Berzin teaches receiving a request for a path in a Segment Routing network from a first node to a second node (Berzin [0014], request to route traffic between a first device and an edge computing, [0065] “segment routing” is used);
determining a shortest path utilizing a Constrained Shortest Path First (CSPF) algorithm with a sorting criteria used as a metric in the CSPF algorithm (Berzin [0067] the path computation model uses a CSPF algorithm.
Berzin teaches the above but Berzin does not explicitly teach utilizing a modified Yen's algorithm to determine one or more additional paths based on diversions from the shortest path, wherein the modified Yen's algorithm explores the diversions based on the pruning criteria; and providing a plurality of paths as a response to the request, wherein the plurality of paths include each of the shortest path and the one or more additional paths that pass the pruning criteria. However, in a similar field of endeavor, Yen teaches utilizing a modified Yen's algorithm to determine one or more additional paths based on diversions from the shortest path, wherein the modified Yen's algorithm explores the diversions based on the pruning criteria (Yen pg. 502 depth of 30 paths is the pruning critieria);
and providing a plurality of paths as a response to the request, wherein the plurality of paths include each of the shortest path and the one or more additional paths that pass the pruning criteria (Yen Fig. 2a illustrates the shortest paths and additional paths).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the invention to incorporate the teachings of Yen to offer a quick selection of an alternate path when encountering temporary disconnection of the active shortest path thus providing constraint-compliant paths that can be used for backup or load balancing.
Berzin-Yen teach the above, but Berzin-Yen do not explicitly teach a Maximum Segment Depth (MSD) which is per-node limit on how many Segment Routing instructions are stacked in a packet header. However, in a similar field of endeavor, NPL teaches a Maximum Segment Depth (MSD) which is per-node limit on how many Segment Routing instructions are stacked in a packet header (NPL section “Introduction” provides “When Segment Routing (SR) paths are computed by a centralized controller, it is critical that the controller learn the Maximum SID Depth (MSD) that can be imposed at each node/link on a given SR path. This ensures that the Segment Identifier (SID) stack depth of a computed path doesn’t exceed the number of SIDs the node is capable of imposing”).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the invention to incorporate the teachings of NPL in the Berzin-Yen system to ensure that the stack depth of a computed path doesn’t exceed the number of SIDs a node is capable of imposing as that would cause a path computation failure and thus, pruning any paths that would not meet this requirement.
Berzin-Yen-NPL teaches the above including diversions based on pruning criteria but Berzin-Yen-NPL does not explicitly teach wherein this is by excluding a root path for a diversion when a segment list length of the root path exceeds the MSD. However, in a similar field of endeavor, Tantsura teaches excluding a root path for a diversion when a segment list length of the root path exceeds the MSD (Tantsura fig.8A elements 805, 810, 815 and corresponding written description provides “…performing a path-finding process using the received MSD value as a constraint such that any selected path will not have a corresponding number of SIDs that exceeds the MSD value”).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the invention to incorporate the teachings of Tantsura in the Berzin-Yen-NPL system to ensure that the stack depth of a computed path doesn’t exceed the number of SIDs a node is capable of imposing as that would cause a path computation failure and thus, pruning any paths that would not meet this requirement.
Regarding claim 2, wherein the modified Yen's algorithm explores the diversions based on the pruning criteria by excluding a root path for a diversion if the root path does not meet the pruning criteria (Yen pg. 502, 30 paths is the pruning criteria). Motivation provided with reference to claim 1.
Regarding claim 3, wherein the modified Yen's algorithm explores the diversions based on the pruning criteria by (1) excluding a possible path if it extends from a root path that does not meet the pruning criteria, and (2) including another possible path that does not itself meet the pruning criteria if it extends from another root path that does meet the pruning criteria (Yen pg. 502 “Since a path…network”). Motivation provided with reference to claim 1.
Regarding claim 4, wherein the modified Yen's algorithm explores the diversions based on the pruning criteria by examining previous paths to find root paths, spur nodes, and spur paths, to combine into a total path; excluding any of the root paths in the examining when a corresponding root path does not meet the pruning criteria; and adding the total path from the examining to a heap based on the sorting criteria (Yen Fig. 2a). Motivation provided with reference to claim 1.
Regarding claim 6, wherein the providing the shortest path and the one or more additional paths includes providing the shortest path and the one or more additional paths in a sorted order by the sorting criteria (Yen Fig. 3). Motivation provided with reference to claim 1.
Regarding claim 7, wherein the first node is a source, the second node is an intermediate node, and the request further includes a destination, wherein the steps further include performing the determining and the utilizing from the second node to the destination, such that there is a first path computation from the source to the intermediate node and a second path computation from the intermediate node to the destination; and maintaining a heap to add a path from each of the first path computation and the second path computation based on the pruning criteria (Yen 2.2 Some auxiliary functions: whole section). Motivation provided with reference to claim 1.
Regarding claims 8-11 and 13-14, these claims contain limitations found within those of claims 1-4 and 6-7 and the same rationale of rejection applies, where applicable.
Regarding claims 15-18 and 20, these claims contain limitations found within those of claims 1-4 and 6 and the same rationale of rejection applies, where applicable.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: Zhao et al US 2015/0103844.
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/I.R/Examiner, Art Unit 2459
/TONIA L DOLLINGER/Supervisory Patent Examiner, Art Unit 2459
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