Latency-Aware Function Placement, Routing, and Scheduling in TSN-based Industrial Networks

Industrie 4.0 reinforces advanced technology development to realize Time-Sensitive Networking (TSN) with real-time guarantees. The evolution of traditional industrial-automation systems such as Programmable Logic Controllers (PLCs) to cyber-physical systems by means of virtualization is one of the key enhancements. In this paper, we evaluate the impact of the placement of virtual PLCs (vPLCs) at edge clouds in conjunction with scheduling and routing of Time-Triggered (TT) traffic in 802.1Qbv-based industrial networks. We propose two approaches to solve this problem adopting a multi-objective optimization model. In the first approach, we solve separately the problem of placement and scheduling-routing by using a Mixed Integer Linear Programming (MILP) formulation. While in the second approach, we propose a Simulated Annealing (SA)-based meta-heuristic to solve the joint placement, scheduling, and routing optimization problem. We compare both the algorithms for real-world test cases and validate our solutions using the OMNeT++ simulator.