TLHAC: Three-level hierarchical architecture of the controller of the software-defined industrial production network

Abstract

As a key component of the industrial intranet, the production network is the source of data generation and the object of intelligent decision-making. Therefore, it is very important for the management and control of the production network. Currently, software-defined network, as one of the key technologies to break the “two-level and three-level” networking model of factory intranet, provides a centralized control and programmable network management capability for the production network. However, as the number of sensor devices in the production network continues to increase, the current single controller deployed at the industrial intranet router may encounter control latency, single points of failure, and uneven load. For this reason, this paper proposes a three-level hierarchical architecture for Software-Defined Network(SDN) controllers in industrial production networks called TLHAC. TLHAC consists of three levels of hierarchy, with the first level being the primary controller deployed on the router of the production network backbone, the second level being the secondary controllers deployed on the edge gateways of the workshop network, and the third level being the sub-controllers deployed on the wireless sensor nodes in the field. When a secondary controller fails, a control latency optimal migration algorithm based on load capacity limitation called LCL_CDOM is proposed to migrate industrial equipment. In addition, to optimize the deployment of sub-controllers, this paper also proposes a sub-controller deployment strategy based on node importance. The strategy first uses the Technique for Order Preference by Similarity to Ideal Solution(TOPSIS) analysis based on multi-attribute decision-making to comprehensively evaluate the importance of wireless sensor nodes, then uses the improved fuzzy multi-objective particle swarm algorithm (called IFMOBPSO) to optimize the solution and select the optimal deployment position of the sub-controller. This paper conducts simulation experiments on the three-level hierarchical deployment architecture and the optimal deployment strategy of the sub-controller. Simulation results demonstrate that TLHAC reduces the average control latency by 42 %-48 % and the average synchronization latency by 19 %-22 % compared to traditional two-level and Edge-SDN architectures. While IFMOBPSO achieves 8 %-14 % lower average control latency of important nodes and than 9 %-12 % lower average synchronization latency between secondary controllers compare to other meta-heuristic algorithms.