Virtual Network Interface for Redundant Controller Cluster Failover
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Solution Overview
Problem
In conventional high-availability automation systems, users face difficulties in establishing connections as they need to know the specific IP address of either the active or standby automation device, leading to complexities in address management and potential failures if the wrong address is used.
Innovation Solution
A controller cluster is implemented with virtual network interface controllers and redundancy managers that manage a cluster hardware address, allowing access via a single address, ensuring high availability by switching between active and inactive states in case of failures, and using Layer-2 Ethernet frames for communication to maintain robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single IP address is used for the H system, then ease of operation is improved, but device complexity increases due to the need for virtual network interface controllers and address management mechanisms
Solution Approach 1:
A virtual network interface controller is introduced as an intermediary layer between the physical network interface controllers and the protocol stacks. This virtual controller manages a single cluster hardware address that represents the entire H system, while internally routing communications to the appropriate active or standby automation device. Users interact only with this virtual interface, eliminating the need to know about underlying dual-address complexity.
Solution Approach 2:
The patent merges the networking functions of two separate automation devices (master and standby) into a single virtual network interface. This consolidation presents a unified address to external users while maintaining internal redundancy, effectively combining multiple physical interfaces into one logical interface that handles failover transparently.
2Device complexity
If conventional H system addressing is used with separate IP addresses for each device, then device complexity is reduced, but reliability deteriorates because users may connect to the wrong address when a device fails
Solution Approach 1:
The virtual network interface controller acts as a mediator that receives all external communications addressed to the cluster hardware address and intelligently routes them to the currently active automation device. This eliminates the risk of users connecting to an inactive device, as the virtual interface abstracts away the physical device states and ensures communications always reach the functional unit.
Solution Approach 2:
The system implements monitoring mechanisms that track the operational status of both master and standby devices. When a failover occurs, the virtual network interface controller receives feedback about the status change and dynamically updates its routing to ensure continuous availability. This feedback loop maintains reliability by preventing connections to failed devices.
3Loss of information
If users are required to know about redundant automation system architecture, then measurement precision of system state is improved, but ease of operation deteriorates due to the need for special address management knowledge
Solution Approach 1:
The virtual network interface controller serves as an intermediary that shields users from the complexity of redundant system architecture. While the system internally maintains detailed knowledge of device states, failover status, and active/standby configurations, this information is abstracted away from users. They simply interact with the single cluster hardware address without needing to understand underlying redundancy mechanisms.
Data Source
AI summary
A controller cluster for controlling a technical device with a redundant first automation device and second automation device, wherein a virtual network interface controller is arranged in the automation devices between a first network interface controller and a protocol stack, and wherein the network interface controller administers a cluster hardware address in addition to a standard hardware address and thus the controller cluster, despite there being two automation devices, presents itself externally as one device.