HSR and PROFINET IRT bandwidth management in generic embedded systems

Real Time Ethernet systems, when viewed from the OSI layer 2, offer attractive characteristics for developers of generic embedded systems requiring real time communications. An important feature of mission critical systems is media redundancy to ensure connectivity under difficult conditions. Since MRPD, the PROFINET IRT redundancy protocol is not considered useful in non-PROFINET environments we investigate the use of HSR as a redundancy protocol and show that whilst an implementation does not necessarily scale well to non real-time traffic, HSR is certainly useful for hard real-time scheduled traffic in generic (non-automation) applications.