Semantic Analysis for Network Intent Rule Shadowing Detection

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Solution Overview

Problem

Complex network configurations lead to error-prone configuration processes and challenging troubleshooting, as conventional methods struggle to determine the equivalence and consistency between software-defined network (SDN) logical and hardware models, resulting in potential misconfigurations and performance issues.

Innovation Solution

The implementation of semantic analysis on Reduced Ordered Binary Decision Diagrams (ROBDDs) to identify shadowed or aliased rules within network intents, ensuring that constituent rules are unique and non-overlapping in terms of their effect on network traffic and actions, thereby providing network assurance and root cause analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If network operators use a wide array of configuration options to tailor the network to user needs, then flexibility and control over the network are improved, but device complexity and error-proneness increase

Engineering Contradiction:

Improveflexibility and controlVSAvoidconfiguration complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary system that automatically analyzes network configurations using semantic analysis and ROBDDs to detect shadowing rules. This mediator bridges the gap between complex configuration options and reliable network operation, preventing errors without restricting flexibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary semantic analysis and conflict detection before network configurations are deployed. By identifying shadowing rules and inconsistencies in advance, the system prevents configuration errors from occurring, allowing operators to use complex configuration options safely.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If conventional methods are used to determine equivalence between SDN logical and hardware models, then configuration verification is performed, but measurement precision and detection capability are insufficient

Engineering Contradiction:

Improveconfiguration verificationVSAvoidequivalence detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces conventional mechanical comparison methods with semantic analysis and ROBDD-based equivalence checking. This substitution enables precise detection of shadowing rules and configuration inconsistencies by analyzing the semantic meaning of configuration statements rather than just comparing syntax.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system transforms configuration verification from simple syntax comparison to semantic equivalence analysis by changing the verification parameters. It evaluates whether configurations produce the same network behavior and effects, providing much higher detection precision for equivalence between logical and hardware models.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If semantic analysis on ROBDDs is implemented to identify shadowed rules, then measurement precision and conflict detection are improved, but device complexity and processing requirements increase

Engineering Contradiction:

Improverule shadowing detection accuracyVSAvoidprocessing system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the network configuration analysis into distinct components: ROBDD construction from configuration statements, semantic meaning extraction, shadowing rule detection, and conflict identification. This segmentation allows each component to be processed independently, managing complexity while maintaining high detection precision.

Inventive Principle:

Principle #1Segmentation

4Reliability

If comprehensive network configuration analysis is performed to identify all shadowing rules, then reliability and troubleshooting capability are improved, but loss of time and processing overhead increase

Engineering Contradiction:

Improvenetwork assuranceVSAvoidanalysis time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary semantic analysis and ROBDD construction during configuration validation, before network operations begin. By detecting shadowing rules and conflicts in advance, it ensures network reliability without adding time overhead during actual network operations and troubleshooting.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10505816B2Semantic analysis to detect shadowing of rules in a model of network intents

Publication Date: 2019.12.10 CISCO TECHNOLOGY INC

AI summary

Systems, methods, and computer-readable media for performing semantic analysis to identify shadowing events. One or more models of network intents, based at least in part on a priority-ordered listing of rules representing network intents, is received. Each rule comprises a Boolean function of one or more packet characteristics and network fabric conditions, and a corresponding network action. For each given rule of the priority-ordered listing of rules, partial and complete shadowing events are detected based on semantic analysis. The semantic analysis comprises calculating an inverse set that comprises the inverse of the set comprising all rules with a higher or equal priority to the given rule, and then calculating a shadowing parameter that comprises the intersection between the inverse set and the given rule. If the shadowing parameter is equal to zero, a complete shadowing event is detected. If the shadowing parameter is not equal to zero and is not equal to the given rule, a partial shadowing event is detected.