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Today many hybrid (wired & wireless) industrial communication networks with a huge variety of heterogeneous technologies and protocols are present in the manufacturing and automation domain. The increasing requirements regarding e. g., latency, reliability, or determinism create the need for a holistic network management concept in order to assure a network-wide Quality-of-Service (QoS) resource provisioning and the assurance of the admissioned resources. Consequently, a monitoring of the whole network is required to feed the network management system with the needed information about the underlying network processes. Various technical approaches using different methods of extracting the information from network traffic are available for the purpose of QoS parameter observance and measurement at the moment. Therefore, this paper provides a state of the art research about network management and QoS provisioning respectively QoS assurance concepts. In addition, the passive network monitoring approach using the flow export technique based on the Internet Protocol Flow Information Export (IPFIX) is investigated for a utilisation in the nowadays industry domain based on a conceptual case study with a wireless protocol. As a conclusion, an evaluation is performed in order to clarify the limits and the overall usability of IPFIX for the monitoring of industrial networks in order to support future network management systems.

Many network applications like motion control or precise monitoring of machines need precise knowledge about the time synchronization accuracy. But time synchronization accuracy depends on the performance of PTP nodes, network topology, environmental conditions and various other factors. This makes the determination of synchronization accuracy a complex task. A mechanism for determining the worst case synchronization accuracy is defined in the PTP Power Profile. A TLV is used for accumulating a vendor defined worst case inaccuracy. However in practice when using this approach the inaccuracy values are often much higher than the real synchronization accuracy. In this paper, a technique for automatic determination of synchronization path quality is investigated. It utilizes PTP Bridges with an inaccuracy estimation performed using an inaccuracy model that is separated into static and dynamic inaccuracy contributors. One assumption is that the inaccuracy in the PTP time observed by a bridge, depends on the position of the bridge in the sync path. The latter is due to accumulation of more, possibly independent, random contributors. The effect of increasing deviation is modeled and verified using an experimental setup. The paper concludes that detailed knowledge about the PTP network (cable lengths, inaccuracy contribution metrics for the specific nodes within the sync path, etc.) are useful for automatic determination of the synchronization path quality, synchronization monitoring, system configuration and diagnosis. We suggest an enhancement to the TimeInaccuracy TLV that may possibly be incorporated within the next PTP revision, to better facilitate the protocol support for the above functions

ZusammenfassungBei der Nutzung von IEEE Standards mit dem Schwerpunkt Time Sensitive Networks (TSN) gibt es unterschiedliche mögliche Nutzungskonzepte. Zwei wesentliche Konzepte können unterschieden und anhand von Kriterien verglichen werden. Diese Nutzungskonzepte sind in Bezug auf das Netzwerk diversitär und haben je nach Nutzungskontext Vorteile und Nachteile. Während ein Konzept unter Nutzung von Preemption und Strict Priority in Netzwerken mit skalierter Datenrate Vorteile im Bereich von Speichergrößen der Bridges und Bandbreitennutzung für Best Effort-Daten zeigt, bietet Time Aware Shaping (TAS) insbesondere in Netzwerksegmenten mit einer Datenrate von 100 MBit/s eine kleinere Latenzzeit.

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