Shared VLAN Traffic Prioritization for Deterministic Industrial Networks

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Solution Overview

Problem

Industrial networks often require deterministic behavior but separating networks leads to fragmentation and security issues, while sharing a network can result in critical traffic failing to get required capacity.

Innovation Solution

Implementing Rate-Limited VLANs with prioritization and bandwidth limitations in a shared physical network to ensure critical traffic gets its required capacity, while maintaining security and predictability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If networks are separated to ensure deterministic behavior, then critical traffic gets guaranteed capacity, but network fragmentation occurs and information exchange becomes difficult

Engineering Contradiction:
Improvedeterministic behaviorVSAvoidnetwork fragmentation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the network into multiple VLANs (Virtual Local Area Networks) that share the physical infrastructure. Each VLAN can be configured with specific QoS policies to ensure deterministic behavior for critical traffic while allowing information exchange across the shared network. This resolves the contradiction by providing logical separation without physical fragmentation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a unified network infrastructure that serves multiple functions: carrying both critical deterministic traffic and non-critical information exchange traffic simultaneously. By using VLANs and QoS mechanisms, the single physical network performs multiple roles that previously required separate networks, eliminating fragmentation while maintaining reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If all automation equipment shares the same physical network, then information exchange is simplified, but critical traffic may fail to get required capacity

Engineering Contradiction:
Improveinformation exchangeVSAvoidcapacity guarantee
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies different quality characteristics to different traffic flows within the shared network. Through QoS mechanisms, critical traffic receives high priority with guaranteed bandwidth, while non-critical traffic uses remaining capacity. This local differentiation of service quality allows simplified information exchange while ensuring capacity guarantees for critical operations.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts network parameters such as bandwidth allocation, priority levels, and queue management for different traffic types. By changing these parameters based on traffic requirements, the system maintains both ease of information exchange and reliability of critical traffic capacity in the shared network.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If VLANs are used to consolidate control networks, then network fragmentation is reduced, but deterministic behavior guarantees are not provided

Engineering Contradiction:
Improvenetwork consolidationVSAvoiddeterministic behavior
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent configures QoS policies and bandwidth reservations in advance before critical traffic flows occur. By pre-establishing priority queues, bandwidth allocations, and traffic shaping rules in the VLAN configuration, the system ensures deterministic behavior is already in place when critical traffic needs to flow, without requiring real-time adjustments.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If network separation is implemented for security, then security level is improved, but information availability for automation functionalities is reduced

Engineering Contradiction:
ImprovesecurityVSAvoidinformation availability
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent uses VLAN segmentation to create logical security zones within the shared physical network. Critical automation equipment can be placed in restricted VLANs with controlled access, while allowing necessary information exchange through configured inter-VLAN routing and access control lists. This provides security without complete isolation, maintaining information availability for automation functionalities.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4181470B1Deterministic behavior in a shared physical network
Publication Date: 2025.12.31 ABB (SCHWEIZ) AG
  • EP4181470B1 patent drawingFigure 1
  • EP4181470B1 patent drawingFigure 2~5

AI summary

A method for providing a deterministic behavior in a shared physical network is disclosed. The method may be performed in a device controlling a Virtual Local Area Network, VLAN, of the shared physical network. The method comprises rate limiting amount of inbound traffic for each traffic flow in the VLAN and assigning a respective priority for each traffic flow in the VLAN.