Network Guard Self-Check for Fault Localization in Data Transmission

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Solution Overview

Problem

Existing bidirectional network guards for secure communication between networks with different security levels are vulnerable to manipulation and errors, lacking effective fault detection and localization mechanisms.

Innovation Solution

A transmission device with independently operating communication and one-way communication devices that can detect, identify, and locate faults within or between components by evaluating operating states using test messages with identification and security information, and employing cryptographic checks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bidirectional network guard is used for secure data transfer between networks with different security levels, then data transmission security is improved, but vulnerability to manipulation and errors increases due to lack of fault detection mechanisms

Engineering Contradiction:
Improvedata transmission securityVSAvoidvulnerability to manipulation and errors
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements preliminary fault detection by sending test messages through internal communication links before normal data transmission. The transmission device proactively identifies potential faults in communication devices and one-way communication devices, allowing preventive measures to be taken before manipulation or errors can compromise security.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent establishes a feedback mechanism where test messages are sent through the transmission device and the response is evaluated to determine operating state. This continuous monitoring provides real-time feedback on the security and integrity of the bidirectional network guard, enabling detection of manipulation attempts and errors that would otherwise compromise data transmission security.

Inventive Principle:
Principle #23Feedback

2Reliability

If fault detection and localization mechanisms are added to the transmission device, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvefault detection capabilityVSAvoidtransmission device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes existing communication devices and one-way communication devices perform multiple functions: normal data transmission and fault detection through test messages. By utilizing the same communication paths and devices for both purposes, the patent avoids adding separate dedicated fault detection hardware, thereby improving reliability while minimizing increases in device complexity.

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

Solution Approach 2:

The transmission device performs self-diagnosis by independently sending test messages through its internal communication links and evaluating the responses to determine its own operating state. This self-service approach to fault detection eliminates the need for external monitoring systems, improving reliability through continuous monitoring while keeping the device complexity manageable.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If test messages are sent through all communication devices to verify operating state, then fault localization precision is improved, but data transmission overhead increases

Engineering Contradiction:
Improvefault localization precisionVSAvoiddata transmission overhead
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent segments the fault detection process by having different communication devices and one-way communication devices send test messages through specific internal communication links. This segmentation allows precise localization of faults to specific components or links while optimizing the test message paths to minimize redundant transmissions and reduce data transmission overhead.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3977681B1Transmission device for transmitting data
Publication Date: 2025.12.31 SIEMENS MOBILITY GMBH
  • EP3977681B1 patent drawingFigure 1
  • EP3977681B1 patent drawingFigure 2~3
  • EP3977681B1 patent drawingFigure 4

AI summary

Proposed is a transmission device (1) for transmitting data between a first network (NW1) and a second network (NW2). The transmission device (1) comprises: a first communication device (2) having a first interface device (6) for coupling to the first network (NW1), a receiver port (12) and a transmitter port (8); a second communication device (3) having a second interface device (7) for coupling to a second network (NW2), a receiver port (13) and a transmitter port (9); a first one-way communication device (4) having a reciever port (14) for receiving messages and a transmitter port (10) for sending messages; and a second one-way communication device (5) having a receiver port (15) for receiving messages and a transmitter port (11) for transmitting messages, wherein at least one selected communication device or one-way communication device (2, 3, 4, 5) is designed to transmit a test message (PN) via its transmitter port (8-11), and to evaluate, at its receiver port (12-15), the test message (PN) for determining an operating mode of the transmission device (1), which test message is transmitted back to the selected communication device or one-way communication device (2-5) internally via the other communication devices (2, 3) and one-way communication devices (4, 5) and/or is supplemented with test data (II, SI).