Industry 4.0 and the vision of smart factories drive the need for real-time communication. Time-Sensitive Networking (TSN) augments the IEEE Std 802.1Q with a family of mechanisms enabling real-time communication. One of the key mechanisms is the Time-Aware Shaper (TAS) implementing a TDMA scheme on a traffic class basis. With proper synchronization it can even be used to schedule individual frames or streams. With this capability, the network can guarantee communication deadlines, bounded latency, and bounded jitter. However, for these guarantees a system-wide schedule needs to be calculated, which is an NP-hard problem. Current approaches are mainly based on constraint programming and optimization problems, and, therefore do not scale well for larger topologies and number of streams. In this paper, our contribution is twofold: first, we propose a scheduling model for converged networks supporting different traffic types and, secondly, we introduce a novel procedure for schedule planning of isochronous traffic which exploits the hierarchical structure of factory networks. To this end, we split the network into sub-networks and use a two-stage approach based on a heuristic and tracing. Our evaluation shows that the new scheduling approach outperforms the reference scheduler by more than two orders of magnitude with regard to execution time.

The industrial communication market is dominated by Ethernet-based fieldbus systems. Although they share similar requirements and market segments, their implementations and ecosystems differ considerably. As a result, end customers and device manufacturers are faced with a multitude of technologies that need to be produced, run, diagnosed, maintained, and kept in stock. Although the availability of products and services is largely satisfactory, dealing with multiple solutions generates high costs and limits IoT capability. This paper introduces Open Platform Communication Unified Architecture Time-Sensitive Networking (OPC UA TSN) as a new technology and presents the current view. This time, the industrial prospects of fulfilling industrial communication requirements while leveraging the cost benefits of standard Ethernet hardware in the midterm are in reach. We anticipate that OPC UA TSN will reveal itself as a game changer in the field of industrial automation, being a candidate for establishing a holistic communication infrastructure from the sensor to the cloud.

With Audio and Video Bridging (AVB), the Institute of Electrical and Electronics Engineers (IEEE) AVB task group introduced Real-Time capabilities to Ethernet based on IEEE 802 Standards. As AVB was conceived with a focus on home and professional audio and video transmissions, some mandatory aspects for the application in industrial control networks are not covered. Under the name of Time-Sensitive Networking (TSN), second generation AVB standards are being developed to address the requirements of industrial automation and control networks, and automotive in-vehicle networks. One of the mandatory requirements addressed by TSN is a redundancy feature to achieve fault tolerance. This paper compares two methods for implementing fault-tolerant networks with the stream registration mechanisms that are planned for TSN.

This paper gives a simple introduction to Network Calculus (NC), a theory to calculate end-to-end delay bounds for packet-switched communication networks. It illustrates how various networking parameters affect delay bounds when flows are multiplexed. Various algorithms for the calculation of end-to-end delay bounds are revisited and their performance is compared under different conditions. The framework is applicable to feedforward networks and useful to determine delay bounds for flows in Ethernet networks.

Downtimes of failed devices in an industrial plant must be kept to a minimum to achieve high system availability. Since failures are often caused by transient hardware- or software faults, a well-defined System Self Diagnosis (SSD) functionality is an important feature for the effective long-term operation of industrial plants. To achieve effective SSD techniques for network infrastructure devices, a root cause analysis of past failures was conducted and a fault model derived. A set of error detection methods was derived based on the checked root cause indicators. For productive deployment, an extensible SSD framework in form of a rule based system was designed and implemented to be used as an embedded software tool throughout the whole product lifecycle of an industrial device, achieving a highly efficient “Design for Testability” approach.