Segment Routing Candidate Path Validation by SL Weight Thresholds

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Solution Overview

Problem

Existing methods for determining the validity of candidate paths in segment routing (SR) policies are unreliable, leading to potential failures in traffic carrying due to insufficient valid segment lists (SLs) or inadequate weight distribution, which can result in traffic interruption.

Innovation Solution

Implementing a validity control parameter to determine the validity of candidate paths by ensuring a minimum number, weight, or weight percentage of valid SLs, using parameters like valid_SL_num, valid_SL_weight, and valid_SL_weight_percent, and notifying these parameters through protocols such as BGP, BGP-LS, PCEP, and NETCONF/YANG, to ensure reliable traffic carrying.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the existing method for determining candidate path validity is used (as long as one SL in a CP is valid, the CP is considered valid), then the determination process is simple, but the reliability of traffic carrying is insufficient

Engineering Contradiction:
Improvereliability of candidate path validity determinationVSAvoidcomplexity of validity determination
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces validity control parameters (valid_SL_num, valid_SL_weight, valid_SL_weight_percent) to change the determination criteria from a simple binary check to a multi-parameter evaluation. This allows the system to require a minimum number of valid SLs, minimum total weight, or minimum weight percentage, thereby improving reliability while maintaining manageable complexity through configurable thresholds

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the validity determination result is used to control whether the candidate path can be selected for traffic carrying. The system continuously evaluates the candidate path against the validity control parameters and provides feedback to the path selection process, ensuring that only paths meeting the reliability criteria are selected

Inventive Principle:
Principle #23Feedback

2Reliability

If the existing validity determination method is used, then the implementation is straightforward, but traffic interruption may occur when valid SLs are insufficient

Engineering Contradiction:
Improvetraffic carrying reliabilityVSAvoidease of implementation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent performs preliminary validity evaluation of candidate paths before traffic is assigned. By pre-calculating whether a candidate path meets the validity control parameters (minimum number of valid SLs, minimum weight requirements), the system prevents traffic interruption before it occurs, ensuring that only paths with sufficient capacity and redundancy are selected for traffic carrying

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the existing validity determination method is used, then the system is simple to operate, but load sharing effectiveness is reduced

Engineering Contradiction:
Improveload sharing effectivenessVSAvoidcomplexity of validity control
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces weight-based validity control parameters (valid_SL_weight and valid_SL_weight_percent) that enable effective load sharing evaluation. By requiring that the sum of weights of valid SLs meets a minimum threshold or percentage, the system ensures that sufficient capacity is available for load sharing, improving productivity while the configurable parameters keep the control complexity manageable

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4718809A1Method for determining validity of candidate path, and electronic device and storage medium
Publication Date: 2026.04.01 ZTE CORP
  • EP4718809A1 patent drawingFigure 1~3
  • EP4718809A1 patent drawingFigure 4~5
  • EP4718809A1 patent drawing

AI summary

Provided are a method for determining validity of a candidate path, an electronic device, and a storage medium. The method includes acquiring a validity control parameter for a candidate path under a segment routing policy; and determining validity of the candidate path according to the validity control parameter, where in response to the candidate path satisfying the validity control parameter, the candidate path is valid.