POWERLINK distinguishes between real-time domains and non real-time domains. This separation matches typical machine and plant concepts. It also satisfies the increasing security demands to prevent hacker attacks at the machine level or harm through erroneous data communication on higher network hierarchies. True real-time requirements are met within the real-time domain. Less time critical data is routed transparently between the real-time domain and non-real-time domain using standard IP frames. A clear boundary between a machine and factory network prevents potential security flaws from the very beginning while keeping full data transparency.