Network fabric redundancy in NCS

Fault-tolerance is becoming an increasingly crucial aspect of the design of Networked Control Systems (NCSs) in order to mitigate system downtime. However, the introduction of fault-tolerance is typically associated with significant traffic overhead. In this paper, an optimization to an Ethernet-based network fabric fault-tolerant NCS is proposed. The proposed optimization halves the amount of overhead traffic necessary for fault-tolerance while maintaining the same level of robustness. Moreover, based on the same optimization methodology, an expanded model with two in-line cells is presented and subsequently tested. The expanded two-cell model is designed to provide controller-level in addition to fabric-level fault-tolerance. Simulations using OPNET followed the traffic analysis, and proved the models to be fully reliable in the case of a single failure at a time, for both the single-cell model and the expanded two-cell network.