Switching Device Broadcast Control for Train Network Segmentation

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Solution Overview

Problem

In network systems, particularly in trains, it is challenging to limit the broadcast range effectively, making it difficult to divide devices into groups corresponding to individual cars and manage broadcasts within and across the network.

Innovation Solution

A network system with multiple subnetworks connected through switching devices that block broadcast signals with specific logical port numbers, allowing for the limitation of broadcast access within designated subnetworks or across the entire network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a broadcast is used to transmit data to all devices in the network, then all devices receive the broadcast data, but it becomes difficult to divide devices into groups corresponding to respective cars and limit the broadcast range to specific subnetworks

Engineering Contradiction:
Improvebroadcast capabilityVSAvoidnetwork management complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The network is divided into multiple subnetworks (first subnetwork and second subnetwork) corresponding to different vehicles. Each subnetwork is managed by a dedicated switching device that can independently control broadcast signal passage. This segmentation allows broadcasts to be limited to specific vehicle groups while maintaining overall network connectivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different quality control is applied to different parts of the network. The switching devices are configured with specific logical port numbers that determine whether broadcast signals are allowed to pass. This enables selective broadcast propagation where certain subnetworks receive broadcasts while others do not, based on local configuration requirements.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If broadcast signals are allowed to pass through all switching devices, then all devices in the network receive the broadcast, but it is impossible to limit the broadcast domain to specific subnetworks

Engineering Contradiction:
Improvebroadcast domain controlVSAvoidnetwork security
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

Switching devices act as intermediary components between different subnetworks. They inspect broadcast signals and make decisions about whether to allow passage based on the logical port number. This intermediary function provides controlled access between subnetworks, enhancing security while maintaining adaptability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses logical port numbers as a parameter to control broadcast signal behavior. By changing or assigning specific logical port numbers to different subnetworks, the system dynamically controls which broadcasts are allowed to propagate, providing flexible domain management and security control.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the network is divided into multiple subnetworks with switching devices, then broadcast range can be limited, but the device complexity and configuration requirements increase

Engineering Contradiction:
Improvenetwork structureVSAvoidsystem implementation
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The switching devices perform multiple functions: they route individual addressed packets, control broadcast signal passage based on logical port numbers, and manage connections between subnetworks. This multi-functionality reduces the need for separate dedicated devices for each function, simplifying overall system implementation despite the network division.

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

Data Source

PatentEP2750333B1Network system
Publication Date: 2017.07.19 MITSUBISHI ELECTRIC CORP
  • EP2750333B1 patent drawingFigure 1~2
  • EP2750333B1 patent drawingFigure 3~4

AI summary

To provide a network system including a network constructed by combining a plurality of switching devices 1 to 5. The network includes a first subnetwork including switching devices 1 to 3 and a second subnetwork that is formed outside the first subnetwork and includes switching devices 4 and 5. The switching device 2 in the first subnetwork connected to the second subnetwork blocks passage of a broadcast signal that is transmitted from a terminal device 6 and that has a specific logical port number as transmission information at a physical port 12.