We investigate the application of a recently published metric for flexibility in the context of combined port queue schedules of network paths in Time-Sensitive Networks (TSN). TSN comprises a set of specifications for deterministic networking, including support for scheduled traffic with guaranteed deterministic end-to-end delays. Typically, scheduler resource allocation in TSN disregards flexibility of scheduler configurations. Essentially, the notion of flexibility of paths comprising multiple concatenated ports having each a TSN configuration is based on the number of possible embeddings, i.e., resource allocations, for a new flow of a given specification (size and delay deadline) along that path. This demonstration allows the user to define TSN schedules along network paths and, hence, illustrates the behavior and benefit of performing flexibility-aware TSN configuration.

Time-Sensitive Networking emerged as a convergent Ethernet-based real-time networking standard for industrial applications. To support real-time, jitter-free isochronous traffic the corresponding TSN mechanism denoted Time Aware Shaper requires special hardware support. In this work, we propose a path to building TSN networks on top of programmable switches. Specifically, we show here how to leverage a data structure amenable to programmable data planes known as Push-in First-out (PIFO) queue to support TSN traffic scheduling for isochronous real-time, as well as, best effort traffic.

In Time-Sensitive Networks (TSN) applications with the highest real-time flow requirements are deployed using the Time-Aware Shaper which requires careful planning and scheduling of flows before deployment. Such deployments lack support for dynamic industrial scenarios such as modular machine assembly and reconfiguration, which require a flexible transition between real-time tasks. In contrast, state-of-the-art techniques rely on flow rescheduling and deployment in conjunction with undesired network downtime. Existing works on adapting schedules to traffic admissions are limited in their ability to choose suitable flows to account for future tasks. In this paper, we aim to leverage the flexibility of scheduler configurations to enable TSN dynamic reconfigurability at runtime. We propose a notion of flexibility for TSN Time-Aware Shaper schedules which we utilize to decide the admissibility of consecutive real-time tasks.

A key aspect of 5G is the facilitation of network convergence. It enables the support of a broad range of use cases including real-time applications over the same shared network infrastructure. One major challenge in addressing the various latency requirements is the efficient sharing of resources for heterogeneous services under the presence of different scheduling timescales. State-of-the-art solutions propose preemptive approaches to satisfy instantaneous time-critical demands, which however can deteriorate the communication for preempted users as well as the overall rate efficiency in the network. We propose a slicing method tailored for deterministic traffic, as commonly found in industrial applications. By exploiting deterministic properties of resource demands, we determine an optimal share of reserved and preempted resources on a per-slot basis to efficiently satisfy all time-critical demands. Additionally, we introduce a preemption restricted slice to protect users with higher reliability requirements. Under this proposed model, we derive an online scheduling algorithm which maintains a better fairness and higher throughput compared to state-of-the-art solutions under high demand of deterministic traffic.

Wireless control applications will play a fundamental role in future factory environments to enable novel mobility use cases and achieve the desired flexibility in production. The standardized integration of 5G into a time-sensitive networking (TSN) environment defines the joint architecture and communication interfaces between the different networks to support time-critical applications. Managing and scheduling such a network in an end-to-end fashion to guarantee the stringent QoS requirements is however a complex task. In this work, we present an efficient window-based resource allocation method for the end-to-end network. A big challenge in scheduling periodic and time-critical control applications over a wireless system is the uncertainty of the channel. We hence introduce a fading correlation-aware optimization to find robust schedules. Our simulation study shows that this approach is able to reduce peak resource demands and hence improve the schedulability compared to standard channel-unaware TSN scheduling.

While the industry is continuously evolving towards more flexible and modular manufacturing environments, simultaneously requirements on the industrial network infrastructure are changing. Network convergence, flexibility in configuration with support of hard real-time end-to-end guarantees are playing a key role. A technology supporting these features is Time-sensitive Networking (TSN). The extension with TSN-over-5G to additionally support mobile use cases brings us one step closer towards a unified and converged wireless and wired network architecture, as needed for future manufacturing environments. At the same time, management and configuration of such large converged networks to guarantee real-time capabilities becomes inherently complex. In this work, we present a joint configuration approach that enables end-to-end scheduling optimization over a bridged network consisting of TSN and logical 5G bridges. We derive suitable network constraints and optimization strategies and apply constraint programming to determine feasible scheduling solutions. By providing numerical results from a simulative study, we show the effectiveness of our proposed end-to-end framework in terms of resource efficiency and support of concurrent users in the network.

Increasing heterogeneity of industrial network systems is a fact and the chances that in the future one communication standard will be able to fulfill the requirements of all possible applications are utopian. With the increasing number of communication systems, their management, configuration, and maintenance become a significant issue. Additionally, due to the increasing amount of network services and traffic, the management of available network resources and the possibility of delivering certain levels of communication quality of service, especially across different network solutions becomes a big challenge. Therefore, in this paper a Controller of Controllers (CoC) concept for management of heterogeneous industrial networks is proposed. The concept is designed to support still widely spread legacy fieldbus systems, different Ethernetbased industrial solutions, and potentially upcoming network technologies. The goal is achieved by leveraging state-of-theart architectural concepts such as software-defined networks, which allows for integration of abstract models in network management. The concept is described and discussed by way of a demonstrator concept for a heterogeneous system of fieldbus and Ethernet-based time-sensitive networks.

The overall Industry 4.0 (I4.0) developments combined with the disruptive process of IT-based digitalisation create a vast amount of new opportunities but also challenges for the industrial automation domain. The combination of hybrid (wired & wireless) communication architectures, already widely installed legacy technologies, new approaches, such as Time-Sensitive Networking (TSN) or 5G, and the general heterogeneity of the industrial landscape results in a high configuration complexity. This creates the necessity for future-proof industrial communication network management systems. Therefore, this paper summarises the current state of the art in this area in order to identify the specific requirements towards future industrial network management systems. The most promising candidate is the Software-Defined Networking (SDN) concept. To evaluate SDN as a possible enabler, specified industrial requirements are compared with the current technological and conceptual capabilities of SDN. In addition, drawbacks resulting in future research questions are identified.

Industry 4.0 introduces modern communication and computation technologies such as cloud computing and Internet of Things to industrial manufacturing systems. As a result, many devices, machines, and applications will rely on connectivity, while having different requirements to the network, ranging from high reliability and low latency to high data rates. Furthermore, these industrial networks will be highly heterogeneous, as they will feature a number of diverse communication technologies. Current technologies are not well suited for this scenario, which requires that the network is managed at an abstraction level, which is decoupled from the underlying technologies. In this paper, we consider network slicing as a mechanism to handle these challenges. We present methods for slicing deterministic and packet-switched industrial communication protocols, which simplify the manageability of heterogeneous networks with various application requirements. Furthermore, we show how to use network calculus to assess the end-to-end properties of the network slices.

The need for secured communication between computationally weak wireless devices has driven the development of novel key generation protocols. Various schemes for extracting symmetric cryptographic keys out of wireless channel properties have been proposed during recent years, making the generation protocol more and more efficient for individual applications. However, often these schemes were evaluated based on theoretical models and without considering practical effects. We present a system for PHY-based key generation with two legitimate users as well as a passive attacker of equivalent power and analyze results from practical measurements in real world scenarios. Furthermore we extend practical constraints by considering heterogeneous setups and show the impact onto representative performance indicators.

The generation of symmetric cryptographic keys based on reciprocal channel properties has evolved as a promising approach in recent years, especially for devices with only little computational power. Different schemes individually addressing constraints from special setups have been proposed, but most schemes generally suffer from bad performance in case of (nearly) static scenarios. Addressing this dilemma, we present a novel approach for physical layer based key generation with two static users supported by a third party. In contrast to other solutions, this approach does not rely on special hardware like multiple antennas and does not let the third party know anything about the secret key, as the helper is potentially not fully trusted. The scheme does not evade to other diversity domains, but still exploits temporal and spatial diversity. We present thorough performance and security analysis, also taking a passive attacker into account.