Physical layer redundancy method for fault-tolerant networks

The physical-layer redundancy method is proposed for a fault-tolerant industrial network. The proposed method consists of the fault detection method and the correction method. The fault detection method uses events created by the state transition in the IEEE 802.4 MAC sublayer and the periodic status frame check for fault detection. The fault correction method corrects the fault with automatic physical layer switching to the stand-by physical layer due to the event created by the fault detection method. The proposed method is realized with dual physical layers, the dual channel manager for switching and the redundancy management module that has a fault detection sub-module and a fault correction submodule. The proposed method guarantees high reliability and fast fault-correction in PICNET.