IEC 62439-5:2010(E) is applicable to high-availability automation networks based on the ISO/IEC 8802-3 (IEEE 802.3) (Ethernet) technology. It specifies a redundancy protocol that is based on the duplication of the network, the redundancy protocol being executed within the end nodes, as opposed to a redundancy protocol built in the switches. Fast error detection is provided by two beacon nodes, the switchover decision is taken in every node individually. The cross-network connection capability enables single attached end nodes to be connected on either of the two networks. It cancels and replaces IEC 62439 published in 2008 and constitutes a technical revisi