In this paper we present a proof-of-concept implementation to demonstrate advantages of applying software-defined networking (SDN) to real-time Ethernet (RTE) networks. Potential advantages include the support of arbitrary network topologies, central and dynamic network (re-)configurations, the efficient use of bandwidth, and fast failover mechanisms at network level. To illustrate the advantages we implemented small proof-of-concept setups that demonstrate the features based on OpenFlow and openPowerlink. Finally, we built a practical showcase. Based on our results we believe the concept of a software-defined real-time Ethernet is worth pursuing as it may lay the groundwork for more advanced real-time networks.