The road to an end-to-end deterministic Ethernet

In recent years we have witnessed that switched Ethernet is on the way to get a predominant position in the automation world. From a communication point of view the introduction of the IEEE 802.1p traffic prioritization standard is an important milestone on the road towards deterministic Ethernet, that has made it possible to predict worst case latency over a switched Ethernet infrastructure. However, the missing link with respect to achieving an application-to-application predictable transfer time has been the ability to control the latency behavior within the end-nodes that may cause severe jitter. We present a generic concept for introducing also a prioritization mechanism into the protocol stacks and give arguments for applying these mechanisms within automation networks in order to obtain deterministic Ethernet node-to-node. The argumentation is followed by real-world measurements showing promising results.