Source Address Bit Marking for Network Loop Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In industrial process control and automation systems, the integration of older and newer control network technologies like HONEYWELL Local Control Networks (LCNs) and Fault Tolerant Ethernet (FTE) based HONEYWELL EXPERION Local Control Networks (ELCNs) can inadvertently create network loops, causing messages to propagate indefinitely and overwhelm the system, as native loop prevention safeguards are not effective across both types of networks.
Innovation Solution
The system marks LCN messages by repurposing bits in the source address field of the message header to indicate if a message has previously transited a network device, allowing ELCN bridges to detect and prevent looped messages from re-transiting, thereby breaking the loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LCN and ELCN networks are connected together in complex ways to enable heterogeneous network integration, then network versatility is improved, but network loop detection capability deteriorates
Solution Approach 1:
The patent uses the source address field as an intermediary carrier to transport loop detection information across heterogeneous network boundaries. By embedding loop detection bits in the source address field of LCN messages and having ELCN bridges read and clear these bits, the system enables loop detection in mixed networks without requiring native ELCN protocol modifications, thus resolving the contradiction between network versatility and loop detection capability
Solution Approach 2:
The source address field is made multi-functional by using its existing structure to serve both its traditional addressing purpose and a new loop detection purpose. The same source address field that identifies message origins now also carries loop detection information through specific bit patterns, allowing a single field to perform multiple functions and enabling loop detection across heterogeneous networks without adding separate dedicated fields
2Measurement precision
If message marking is implemented to detect looped messages, then loop detection precision is improved, but device complexity increases
Solution Approach 1:
The system implements self-service by having ELCN bridges automatically read and clear the loop detection bits in the source address field without requiring external control or complex processing. The bridges autonomously perform the marking and detection operations using simple bit manipulation, reducing device complexity while maintaining high loop detection precision through the self-contained nature of the mechanism
3Device complexity
If the source address field is used for marking to indicate message traversal, then device complexity is minimized, but address field functionality is compromised
Solution Approach 1:
The patent applies local quality by making changes only to specific bits within the source address field rather than altering the entire field's functionality. The loop detection bits are embedded in localized positions within the source address field, allowing the field to maintain its primary addressing function while adding loop detection capability in specific local regions of the data structure, thus minimizing impact on overall address field versatility
Data Source
AI summary
A method includes receiving a message having a message header at a network node, where the message header includes a source address field. The method also includes determining whether the message has been previously received at the network node using one or more bits of the source address field. The method further includes, upon a determination that the message has not been previously received at the network node, setting the one or more bits of the source address field to a specified value indicating that the message has been received at the network node. The one or more bits in the source address field are used in a manner that is contrary to original device specifications.