Design of a Realtime Industrial-Ethernet Network Including Hot-Pluggable Asynchronous Devices

This paper presents a new approach to design a realtime Industrial-Ethernet network with the feature to add asynchronous sending devices like laptops or personal computers to the network without affecting the realtime performance. The idea is based on the modification of switching engines with usage of standard cabling and network interface cards. Although the implementation is similar to Siemens ProfiNet IRT, we will point out advantages of our more general approach. As a research result in formal modelling, we present a way to generate bipartite conflict graphs out of a given network infrastructure and communication requests of the devices. This graphs can be colored in polynomial time, which leads to schedules for each switch. Additionally, we discuss possible hardware designs of a modified Ethernet switch.