Redundancy for an all-in-one ISA100.11a Gateway: Protocol Design and Hardware Integration

In order to protect industrial wireless sensor networks against single point of failure, system redundancy implies duplicate Gateway entities and the implementation of a communication protocol that defines and updates the network state. The scope of this paper is to present the design of a redundancy protocol integrated within two hardware entities respecting the ISA100.11a Gateway functionalities. Two types of system redundancy were evaluated considering physical all-in-one Gateway entities, namely cold-redundancy and hot-redundancy. These features reflect the ability of the entire system and MODBUS Server respectively, to react in case of failure by assuring network state, synchronization services, and seamless switchover for the external clients. The performance of the redundancy protocol and its impact on the ISA100.11a network was evaluated in three scenarios that emphasize on the ability of the redundant system to maintain effective communication and recover in case of failure.