Loop Check Packet for Industrial Ethernet Network Break Detection
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Solution Overview
Problem
Existing industrial automation systems, particularly those using PLCs and Industrial Ethernet networks, face challenges in effectively detecting and reporting cable breaks or other network failures within STP or RSTP ring configurations, which can lead to inefficiencies and potential system downtime.
Innovation Solution
A method involving a root node in a loop network transmitting a packet to neighboring nodes, with non-root nodes determining and setting flags to manage packet forwarding, and reporting back to the root node within a predetermined time period to indicate network integrity or failure, allowing for timely detection and reporting of cable breaks or other link failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If STP or RSTP protocols are used to configure the network into rings with blocked ports for redundancy, then network reliability is improved through automatic backup paths, but the ability to detect cable breaks at the application level deteriorates because blocked ports prevent proper failure reporting
Solution Approach 1:
The patent introduces a special intermediary packet (loop check packet) that mediates between the blocked port requirement for redundancy and the need for failure detection. This packet is specially handled by blocked ports - it is forwarded despite the port being blocked, allowing the packet to complete a full loop around the ring and return to the root node to indicate network integrity or failure.
Solution Approach 2:
The patent segments the network monitoring function by having the root node generate and send loop check packets to all other nodes, with each node independently processing and forwarding these packets. This segmentation allows distributed participation in the failure detection mechanism while maintaining centralized coordination through the root node.
2Object-generated harmful factors
If blocked ports are used in STP/RSTP to prevent loops, then broadcast radiation is prevented, but network break detection is hindered because failure information cannot propagate through blocked paths
Solution Approach 1:
The patent applies local quality by giving the loop check packet special properties that differentiate it from regular broadcast traffic. Blocked ports are configured with local quality to recognize and forward this specific packet type even though they block other traffic, thus preventing broadcast radiation while allowing failure information propagation.
Solution Approach 2:
The root node performs preliminary action by generating and sending loop check packets at regular intervals before actual network failures occur. This continuous proactive monitoring ensures that network integrity is verified beforehand, and any breaks are detected immediately when the loop check packet fails to return.
3Stability of the object's composition
If standard STP packet handling is used where blocked ports drop packets, then loop prevention is achieved, but application-level failure reporting is lost
Solution Approach 1:
The patent introduces dynamics by making blocked ports behaviorally dynamic - they normally drop packets to maintain topology stability, but dynamically change behavior to forward loop check packets for failure reporting. This dynamic adaptation allows the system to maintain stability while periodically performing health checks.
Solution Approach 2:
The patent implements feedback by having non-root nodes send acknowledgments back to the root node when they receive loop check packets. The root node uses this feedback to determine network integrity - if acknowledgments are received from all nodes, the network is healthy; if some are missing, cable breaks are detected at the application level.
Data Source
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AI summary
A system, method, and computer readable medium allow a cable break or other network link failure to be detected and reported. The method may include steps of periodically transmitting a packet from a root node in the network to a next node in the network; at each successive non-root node in the loop, manipulating the packet and forwarding the manipulated packet to a next successive node in the loop; when the packet is received back at the root node within a predetermined time period, reporting that the loop is intact; and when the packet is not received back at the root node within the predetermine time period, reporting that a network break has occurred. The network may conform to the STP or RSTP protocols, and may contain one or more rings possibly including dual rings. The PLC may operate as the root node, and the reporting may be done at an application level in the PLC.