Ring Redundant Communication Path Transfer Apparatus Failure Detection
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Solution Overview
Problem
In ring control systems, incorrect detection of failures due to transfer delays or buffer overflows can lead to unnecessary loop generation and path segmentation, disrupting communication in ring redundant communication paths.
Innovation Solution
A method where transfer apparatuses periodically transmit inspection frames and non-arrival notifications to detect failures, close affected ports, and send open commands to maintain path redundancy, ensuring that only necessary ports are opened or closed to prevent loop generation and maintain path integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If spanning tree control methods are used to logically release loops by setting a single port in a blocking state, then loop configuration is released, but path recalculation cost increases and path switching time increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring a main transfer apparatus and sub transfer apparatus with predetermined roles in the ring redundant communication path. The main transfer apparatus closes its control port in advance to logically release the loop, while the sub transfer apparatus keeps its control port open. This pre-established configuration eliminates the need for complex path recalculation during failures, as the system already knows which apparatus should open its port to restore communication.
2Reliability
If the control port of the main transfer apparatus is opened to perform path switching when failure is detected, then path switching is realized, but loop generation occurs due to incorrect failure detection
Solution Approach 1:
The patent implements feedback through the inspection frame mechanism. The main transfer apparatus periodically transmits inspection frames through the ring redundant communication path to detect failures. When a failure is detected (inspection frame not received within predetermined time), the system receives feedback about the actual failure state and only then opens the control port of the main transfer apparatus. This feedback mechanism prevents incorrect loop generation by ensuring port opening is based on confirmed failure conditions.
Solution Approach 2:
The inspection frame acts as an intermediary signal that mediates between the transfer apparatuses and the control logic. Instead of directly reacting to potential failures, the system uses inspection frames as an intermediate verification mechanism to confirm actual failures before triggering port opening. This intermediary approach filters out false positives and prevents unnecessary loop generation.
3Speed
If path switching is performed quickly by opening the control port upon failure detection, then path switching speed increases, but path segmentation occurs due to premature port opening
Solution Approach 1:
The patent applies preliminary action by pre-establishing the role assignment between main and sub transfer apparatuses. The main transfer apparatus is predetermined to close its control port for loop release, while the sub transfer apparatus is predetermined to keep its control port open. This pre-configured division of labor ensures that when failure occurs, only the appropriate port should be opened, preventing path segmentation while maintaining fast switching.
4Measurement precision
If many parameters are treated for path calculation in spanning tree control methods, then accurate path determination is achieved, but device complexity increases
Solution Approach 1:
The patent extracts the essential function of loop release from the complex spanning tree control algorithm. Instead of treating many parameters for path calculation, the system simply closes the control port of the main transfer apparatus to logically release the loop. This extraction of the core function eliminates unnecessary complexity while maintaining accuracy in path determination.
Data Source
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AI summary
In a ring redundant communication path control method, each of transfer apparatuses periodically transmits an inspection frame for inspecting a communication path, detects a failure of the communication path when the inspection frame is not received for a fixed time, transmits a non-arrival notification frame for notifying that the inspection frame has not arrived yet, and detects a failure of the communication path when the non-arrival notification frame is received. Each of the transfer apparatuses closes, when a failure is detection, a port in which the failure is detected, transmits an open command frame for commanding to open a mainly closed port from the other port other than the closed port, transfers an open command frame when the open command frame is received, and opens the mainly closed port when the other port other than the closed port in which the failure is detected, the port in which the open command frame is detected, or the other port configuring a ring redundant communication path same as that of the port is the mainly closed port.