SDN Flow Table Parallel Lookup via Dependency Graph Segmentation

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Solution Overview

Problem

Traditional data networks face complexity and management challenges due to the tight coupling of control and data planes, which hinders scalability, interoperability, and extensibility, especially in Software Defined Networking (SDN) systems where multiple flow tables are used for traffic forwarding, leading to inefficient lookup processes.

Innovation Solution

The method involves determining the dependency of flow tables within a forwarding element using dependency determination rules, constructing a dependency graph, and forming parallel lookup groups (PLGs) based on dependency degree counts, allowing for simultaneous lookup of flow tables with the same dependency degree, thereby optimizing the flow table lookup process in SDN networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple flow tables are used for traffic forwarding in SDN systems, then traffic forwarding flexibility and control are improved, but lookup process efficiency deteriorates due to sequential processing requirements

Engineering Contradiction:
Improvetraffic forwarding flexibilityVSAvoidlookup process efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent segments the flow tables into multiple independent groups that can be processed in parallel. By dividing the single sequential lookup process into multiple concurrent lookup operations on separate flow table groups, the system maintains the flexibility of multiple flow tables while improving lookup efficiency through parallel execution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension of parallel processing by organizing flow tables into multiple independent groups that can be accessed simultaneously. This transforms the traditional single-dimension sequential lookup into a multi-dimensional concurrent lookup structure, where independent flow table groups operate in parallel to improve overall lookup throughput.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If flow tables are processed sequentially to ensure proper dependency ordering, then lookup accuracy is maintained, but processing time increases

Engineering Contradiction:
Improvelookup accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments flow tables into independent groups where dependencies are contained within each group. This allows groups with no inter-group dependencies to be processed simultaneously, reducing total processing time while maintaining lookup accuracy through proper intra-group dependency handling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary analysis to identify and establish dependency relationships between flow tables before the actual lookup process. By pre-determining which flow tables can be processed in parallel and which require sequential processing, the system optimizes lookup accuracy while minimizing processing time through informed parallelization decisions.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If traditional integrated control plane and data plane are used, then system simplicity is maintained, but network management complexity and fragility increase

Engineering Contradiction:
Improvesystem structural simplicityVSAvoidnetwork management ease
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent applies segmentation by separating the control plane and data plane into distinct functional components. The control plane handles flow table management and dependency analysis, while the data plane executes parallel lookup operations. This architectural separation simplifies the overall system structure while improving network management capabilities through specialized functional modules.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2959647B1Method and system for flow table lookup parallelization in a software defined networking (SDN) system
Publication Date: 2017.07.26 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2959647B1 patent drawingFigure 1
  • EP2959647B1 patent drawingFigure 2
  • EP2959647B1 patent drawingFigure 3

AI summary

A method implemented in a Software Defined Networking (SDN) network for flow table lookup parallelization is disclosed. The SDN network contains at least a SDN controller and at least a forwarding element and the SDN network utilizes a plurality of flow tables to perform lookup for forwarding traffic. The method starts with determining dependency of flow tables within the forwarding element using a set of dependency determination rules. A dependency graph is then constructed based on determined dependency of flow tables. A dependency degree count for each flow table within the forwarding element is determined based on the dependency graph. Based on the dependency degree count determination for each flow table, a plurality of parallel lookup groups (PLGs) for the forwarding element is formed, where each parallel lookup group contains one or more flow tables having a same dependency degree count.