Industrial IoT regulated by Software-Defined Networking platform for fast and dynamic fault tolerance application

Software-Defined Networking (SDN) technology has emerged as a promising solution to guarantee high reliability in the Industrial Internet of Things (IIoT) ecosystem. Through SDN, both fault tolerance-based Route Protection (RP) and fault tolerance-based Route Restoration (RR) are available to provide traffic rerouting when a network failure occurs in IIoT. RR redefines routes dynamically based on the current network status. However, it increases significantly the recovery time, which is not suitable for the Quality-of-Service (QoS) requirements of IIoT. In contrary, RP ensures fast failover, but it cannot be updated when the network status changes until the timeout interval expires. To deal with these issues, we propose a Dynamic Route Protection (DRP) mechanism that recalculates and reinstalls new optimal link-disjoint routes in accordance with the change rather than awaiting the controller to retransmit new flow instructions. Moreover, DRP responds speedily to forward the data packets from the secondary route to the main route if it is repaired. To recover rapidly when the connection failure affects both a link on the main route and the link on the secondary route simultaneously, the DRP mechanism utilizes the strategy of caching the third route in the controller memory using the Dynamic Hash Table (DHT) structure. DRP considers the heterogeneous traffic flows such as either delay-sensitive or both delay-sensitive and loss-sensitive. Again, this paper introduces a candidate fault tolerance architecture for Software-Defined IIoT (SDIIoT) that decouples IIoT networks into three functional layers. The results from the simulation network and the experimental hardware testbed illustrated that the DRP mechanism outperforms the FT-RP, RR, LFR, Pro-VLAN, and SDNRMbw mechanisms by minimizing the failure recovery time, end-to-end delay, packet violation rate, packet loss rate, and the time required to reuse the main route when it is repaired, while maximizing the packet delivery ratio.