Dynamic task offloading is essential for real-time robotic applications, enabling them to adapt to fluctuating computational demands and maintain efficiency under changing conditions. This paper introduces a dynamic task offloading framework that incorporates monitoring, decision making, offloading triggering, and performance monitoring to optimize resource usage by offloading real-time tasks to edge and cloud servers. A use case from the manufacturing industry demonstrates the framework’s application, enhancing robotic functions like motion planning. WebAssembly enables the execution of the robotics application across diverse environments, improving both portability and computational efficiency. By addressing key challenges, this work sets the stage for future offloading frameworks to meet the evolving needs of robotic systems.

Time-Sensitive Networking (TSN) has emerged as a key technology for ensuring reliable and deterministic communication in vehicular networks. However, the complexity of evaluating, configuring, and analyzing TSN mechanisms has hindered its widespread adoption. This paper introduces CONAN-TSN, an integrated toolchain designed to address these challenges by providing a comprehensive solution for the configuration, analysis, and evaluation of TSN networks. CONAN-TSN includes tools for traffic generation, traffic mapping, scheduling, and timing analysis, enabling seamless integration and practical implementation of TSN in vehicular systems. The toolchain’s effectiveness is demonstrated through its application to an industrial use case, showcasing its ability to enhance network schedulability and performance. The results highlight CONAN-TSN’s potential to bridge the gap between theoretical benefits and real-world deployment of TSN, offering a valuable resource for researchers and practitioners in the field.

This paper identifies that existing industrial automation standards, such as IEC/IEEE 60802 and IEEE 802.1Q, often have inconsistent definitions of traffic types. In the context of utilizing time-sensitive networking (TSN) standards for future automation systems, clear and consistent traffic characteristics and use cases should be defined to benefit from TSN features. Besides that, to facilitate the integration of TSN into the automation systems, the current standards provide a recommendation for mapping the automation traffic to the TSN traffic classes. In this paper, we propose an alternative mapping methodology for automation traffic to TSN traffic classes after presenting the existing automation traffic and their characteristics. Finally, through a case study, we show the potential of the new mapping methodology compared to the standard mapping strategy.

Multi-Access Edge Computing (MEC) is a paradigm that enables Internet-of-Things (IoT) applications and devices to run tasks in different locations, from IoT devices to servers in the Cloud. This way, less capable devices can offload computation loads to more powerful or available servers. However, choosing the optimal location for a particular task can be complex due to the features of each location and restrictions of the task. For this, numerous approaches in the literature adopt a centralized strategy for the computation offloading decision, which introduces a single point of failure and can be a bottleneck for resource-demanding applications. In this work, we propose a decentralized Deep Reinforcement Learning (DRL) agent to solve the choice of computing locations, and its assessment in a real testbed. This testbed is formed of an end-user device running the agent, which connects to a MEC server and a Cloud server through 5G. We compare the algorithm against four alternatives, one based on another DRL approach, and analyze their performance in terms of meeting the computing tasks’ requirements and energy consumption in the User Equipment (UE), where synthetically generated tasks are executed or offloaded. DRL algorithms are shown to provide the best tradeoff between performance and energy consumption in changing conditions.

Software and system architecture modeling is a well-established technique for addressing design-time challenges and enabling validation early in the system and software development process. However, software and system modeling has not been as widely used in automation systems as it has been in the automotive industry. In addition to validating functional properties through modeling, security properties and features can be evaluated in the modeling phase. This paper provides a brief overview of existing modeling approaches for future automation systems, known as modular automation, that support security modeling and analysis. Modular automation refers to a new trend in automation in which various modules are developed in advance and integrated to build an automation system. Moreover, we study the gaps and missing components of the existing modeling approaches via a use case demonstration. Our study shows that the current state of automation and control system modeling has several limitations that require urgent attention.

To meet the increasing demands of high-throughput manufacturing, modern automation systems are increasingly being designed using a modular architecture, commonly referred to as modular automation. However, due to vendor lock-ins and high upfront investment requirements, the industry relies on existing legacy automation systems that were developed in a non-modular fashion. A major challenge lies in enabling the incremental modernization of legacy systems while ensuring their seamless coexistence with modular automation systems. To address this challenge, we propose a conceptual architecture for a containerized gateway that integrates legacy and modular automation systems. We present initial insights into the feasibility of using containers for such integration via a survey conducted with researchers and practitioners in the automation domain. Furthermore, we discuss an implementation plan for the proposed architecture in the automation industrial settings.

The increasing complexity of modern embedded systems highlights the limitations of Controller Area Network (CAN) in terms of transmission speed and scalability. The IEEE Time-Sensitive Networking (TSN) task group developed a set of standards to enhance switched Ethernet with high bandwidth, low jitter, and deterministic communication. Despite these advances, CAN will likely co-exist with TSN in, e.g., the automotive industry due to factors such as cost-effectiveness and legacy of CAN. This paper presents an experimental evaluation of a CAN-toTSN gateway implementation, focusing on the impact of different forwarding and scheduling strategies on network performance. We analyze various queuing techniques and scheduling mechanisms in a realistic experimental setup and assess their impact on end-to-end delay and TSN bandwidth utilization. The evaluation results demonstrate that encapsulating only a single CAN frame within a TSN frame effectively minimizes the end-to-end delay of CAN frames, in particular when a high-speed TSN network is used. Furthermore, we perform a comparative evaluation of the Time-Aware Shaper (TAS) and Weighted Round Robin (WRR) mechanisms in the TSN network. Interestingly, WRR leads to lower delays for CAN frames in the TSN network compared to TAS, which we attribute to the lack of synchronization between CAN and TSN.

A hybrid cloud is an efficient solution to deal with the problem of insufficient resources of a private cloud when computing demands increase beyond its resource capacities. Cost-efficient workflow scheduling, considering security requirements and data dependency among tasks, is a prominent issue in the hybrid cloud. To address this problem, we propose a mathematical model that minimizes the monetary cost of executing a workflow and satisfies the security requirements of tasks under a deadline. The proposed model fulfills data dependency among tasks, and data transmission time is formulated with exact mathematical expressions. The derived model is a Mixed-integer linear programming problem. We evaluate the proposed model with real-world workflows over changes in the input variables of the model, such as the deadline and security requirements. This paper also presents a post-optimality analysis that investigates the stability of the assignment problem. The experimental results show that the proposed model minimizes the cost by decreasing inter-cloud communications for dependent tasks. However, the optimal solutions are affected by the limitations that are imposed by the problem constraints.

Integrating Time-Sensitive Networking (TSN) with 5G cellular networks facilitates high-bandwidth, low-latency end-to-end communication in networked embedded systems. An integrated TSN-5G network has the potential to support predictable and deterministic end-to-end communication, as well as to significantly enhance scalability, particularly in industrial automation, by providing flexibility, efficiency, and responsiveness. This paper aims to facilitate the end-to-end (E2E) communication over the integrated TSN-5G networks, by addressing two of the main challenges: (1) design and implementation of an effective TSN-5G gateway that not only ensures an effective forwarding mechanism to translate the traffic among both networks, but also maps the TSN traffic to the corresponding 5G quality-of-service profiles to ensure the timing requirements of high-critical traffic, and (2) establishment of clock synchronization across all network components to support the E2E communication in TSN-5G networks. The paper outlines the design and implementation of a robust TSN-5G gateway that bridges TSN and 5G network architectures, ensuring seamless interoperability between them. We utilize a standalone private 5G network within a controlled lab environment to establish the E2E communication for the TSN-5G network, with a particular emphasizes on analyzing latencies and jitter to provide valuable insights for industrial implementation. Moreover, the gateway facilitates a time synchronization approach, to enable time coordination between network components that supports E2E communication on TSN-5G networks considering the hardware limitation. Our findings indicate that achieving latencies below 20 ms is feasible in an integrated TSN-5G network using the proposed configuration of a private 5G setup with a channel bandwidth of 40 MHz.

The Time-Sensitive Networking (TSN) Task Group of the IEEE has proposed standards to provide Ethernet with real-time guarantees, network management and fault tolerance mechanisms. In this way, the Task Group expects Ethernet to become the standard network technology for novel industrial applications with real-time and reliability requirements. TSN proposes to use space redundancy to increase the reliability of the network, but redundancy alone might not be enough to reach the reliability guarantees required by certain applications, such as offshore industrial systems. For this reason, we propose a fault diagnosis mechanism called FAUDI that represents the first step towards automatic online reconfiguration of TSN networks to adapt to faults affecting the network. We present the design of FAUDI and we model it using the UPPAAL model checker, which allows to carry out an exhaustive evaluation of FAUDI's design. We use the model to validate the design and to verify that FAUDI exhibits properties that are of paramount importance in reliable real-time systems.

In an Industrial Control System (ICS), link failures causing partitioning between the redundant controller pair can prevent synchronization. This disruption could potentially trigger incorrect redundancy role-switching procedures. Distinguishing link and node failures from each controller's perspective can effectively mitigate these dependability threats. We introduce an algorithm capable of detecting and differentiating link failures from node failures within a bounded time. The proposed algorithm leverages periodic messages generated by industrial protocols operational in network devices. Our preliminary evaluation indicates the feasibility of the proposed algorithm in terms of meeting the real-time requirements of the ICSs.

Industrial automation and control systems are responsible for running our most important infrastructures, providing electricity and clean water, producing medicine and food, along with many other services and products we take for granted. The safe and secure operation of these systems is therefore of great importance. Reliability is a fundamental requirement, with spatial controller redundancy being one important fault-tolerance mechanism. In current control system solutions, controller redundancy is implemented using state and heartbeat transfer communicated over dedicated physical links, based on an assumption of implicit trust. However, with the emerging network-centric control strategies there is a desire to transition into dynamic redundancy scenarios, where such dedicated links are unfeasible. In this paper, an approach for a threat-model based security analysis is presented from the perspective of the automation industry. The approach is applied to the communication links used for supporting control system redundancy within a network-centric architecture.

As the industry trend is moving toward Ethernet-based Industrial Control Systems (ICSs) in line with the industry 4.0 paradigm, the network traffic must be monitored and managed to keep the systems reliably available. A flat converged network architecture where all the controllers, Input/Output (I/O), and supervisory systems are connected introduces mixed traffic classes competing for network resources and access to the shared medium. These traffic classes are typically managed with different Quality of Service (QoS) techniques. The challenge lies in managing end-to-end QoS in a heterogeneous environment and configuring switches according to the vendor, model, and operating software. Meanwhile, emerging greenfield technology are not deployable with switches used in today's ICS. We propose a distributed QoS supervisory agent, capable of detecting and correcting faulty QoS configurations in a contemporary heterogeneous Layer 2 switch environment. The initial results are achieved through two experimental testbeds in a use case where our agent successfully corrected the QoS configurations.

Time-Sensitive Networking (TSN) has become one of the most relevant communication networks in many application areas. Among several traffic classes supported by TSN networks, Audio-Video Bridging (AVB) traffic requires a Worst-Case Response Time Analysis (WCRTA) to ensure that AVB frames meet their time requirements. In this paper, we evaluate the existing WCRTAs that cover various features of TSN, including Scheduled Traffic (ST) interference and preemption. When considering the effect of the ST interference, we detect optimism problems in two of the existing WCRTAs, namely (i) the analysis based on the busy period calculation and (ii) the analysis based on the eligible interval. Therefore, we propose a new analysis including a new ST interference calculation that can extend the analysis based on the eligible interval approach. The new analysis covers the effect of the ST interference, the preemption by the ST traffic, and the multi-hop architecture. The resulting WCRTA, while safe, shows a significant improvement in terms of pessimism level compared to the existing analysis approaches relying on either the concept of busy period or the Network Calculus model.

Container-based virtualization is a promising deployment model in fog and edge computing applications, because it allows a seamless co-existence of virtualized applications in a heterogeneous environment without introducing significant overhead. Certain application domains (e.g., industrial automation, automotive, or aerospace) mandate that applications exhibit a certain degree of temporal predictability. Container-based virtualization cannot be easily used for such applications, since the technology is not designed to support real-time properties and handle temporal disturbances. This article proposes a framework consisting of a static offline and a dynamic online phase for resource allocation and adaptive re-dimensioning of real-time containers. In the offline phase, the optimal initial deployment and dimensioning of containers are decided based on ideal system models. Additionally, to adapt to dynamic variations caused by changing workloads or interferences, the online phase adapts the CPU usage and limits of real-time containers at runtime to improve the real-time behavior of the real-time containerized applications while optimizing resource usage. We implement the framework in a real Linux-based system and show through a series of experiments that the proposed framework is able to adjust and re-distribute computing resources between containers to improve the real-time behavior of containerized applications in the presence of temporal disturbances while optimizing resource usage.

Abstract The edge-cloud computing continuum effectively uses fog and cloud servers to meet the quality of service (QoS) requirements of tasks when edge devices cannot meet those requirements. This paper focuses on the workflow offloading problem in edge-cloud computing and formulates this problem as a nonlinear mathematical programming model. The objective function is to minimize the monetary cost of executing a workflow while satisfying constraints related to data dependency among tasks and QoS requirements, including security and deadlines. Additionally, it presents a genetic algorithm for the workflow offloading problem to find near-optimal solutions with the cost minimization objective. The performance of the proposed mathematical model and genetic algorithm is evaluated on several real-world workflows. Experimental results demonstrate that the proposed genetic algorithm can find admissible solutions comparable to the mathematical model and outperforms particle swarm optimization, bee life algorithm, and a hybrid heuristic-genetic algorithm in terms of workflow execution costs.

Novel production paradigms aim at increasing the efficiency and flexibility of production systems. Nonetheless, traditional industrial infrastructures lack the mechanisms needed to support these new paradigms. One of the main limiting factors is the architecture, which follows the automation pyramid in which subsystems are divided in layers depending on their functionalities. This allowed to meet the timing and dependability requirements of the production subsystems, however at the cost of limiting the exchange of information required to provide increased flexibility to the system. For this reason, in this paper we propose a new industrial architecture with a single network infrastructure to connect all the devices that conform to the industrial systems. On top of that, we design an Automatic Network Configurator to support the automatic configuration of the system. To assess the feasibility of our design and evaluate its performance, we implement the first instance of the architecture capable of supporting changes in the traffic requirements during run-time, i.e., without stopping or disrupting the system's operation. Furthermore, we use the implemented instance to measure the time required for reconfigurations.

This paper performs a comparative evaluation of various generations of Controller Area Network (CAN), including the classical CAN, CAN Flexible Data-Rate (FD), and CAN Extra Long (XL). We utilize response-time analysis for the evaluation. In this regard, we identify that the state of the art lacks the response-time analysis for CAN XL. Hence, we discuss the worst-case transmission times calculations for CAN XL frames and incorporate them to the existing analysis for CAN to support response-time analysis of CAN XL frames. Using the extended analysis, we perform a comparative evaluation of the three generations of CAN by analyzing an automotive industrial use case. In crux, we show that using CAN FD is more advantageous than the classical CAN and CAN XL when using frames with payloads of up to 8 bytes, despite the fact that CAN XL supports higher bit rates. For frames with 12-64 bytes payloads, CAN FD performs better than CAN XL when running at the same bit rate, but CAN XL performs better when running at a higher bit rate. Additionally, we discovered that CAN XL performs better than the classical CAN and CAN FD when the frame payload is over 64 bytes, even if it runs at the same or higher bit rates than CAN FD.

Offline scheduling of Scheduled Traffic (ST) in Time-Sensitive Networks (TSN) without taking into account the quality of service of non-ST traffic, e.g., time-sensitive traffic such as Audio-Video Bridging (AVB) traffic, can potentially cause deadline misses for non-ST traffic. In this paper, we report our ongoing work to propose a solution that, regardless of the ST scheduling algorithm being used, can ensure meeting timing requirements for non-ST traffic. To do this, we define a frame called Guard Frame (GF) that will be scheduled together with all ST frames. We show that a proper design for the GFs will leave necessary porosity in the ST schedules to ensure that all non-ST traffic will meet their timing requirements.

Wireless Time-Sensitive Networks (TSN) are needed to fulfill the requirements of real-time applications in areas where wired connections are not feasible. Wireless TSN combines the real-time capabilities of TSN with the flexibility of wireless connectivity opening a path for new use cases while providing determinism to time-critical scenarios such as autonomous vehicles. Industrial automation is integrating TSN with various wireless technologies such as WiFi, 4G, and 5G. This paper presents an ongoing work which aim is to experimentally analyze the performance of TSN when integrated with 4G, 5G, and WiFi in real-world scenarios. This will help both the researchers and industries to have a clear view of the network performance regarding the end-to-end latency requirements when designing their applications and use cases.

Container-based virtualization has become a promising deployment model for industrial applications mainly due to its benefits, such as providing support for co-located applications in heterogeneous environments. However, such facilitation brings challenges, including full temporal isolation among real-time applications and support for time-critical applications. In this paper, we tackle such challenges, in particular when the applications are time-sensitive Control Applications. The literature suggests that flexible timing constraints for Control Applications are beneficial in responding to disturbances and minimizing response deviation. Therefore, we propose a mechanism to support such a runtime adaptation in container-based virtualization. To show the performance of the proposed mechanism, we implement our approach on a Linux-based hierarchical scheduling platform, and we evaluate it for a Control application.

Controller Area Network (CAN) and Ethernet network are expected to co-exist in automotive industry as Ethernet provides a high-bandwidth communication, while CAN is a legacy cost-effective solution. Due to the shortcomings of conventional switched Etherent, such as determinism, IEEE Time Sensitive Networking (TSN) task group developed a set of standards to enhance the switched Ethernet technology providing low-jitter and deterministic communication. Considering these two network domains, we investigate various design approaches for a gateway that connects a CAN domain to a TSN domain. We present three gateway forwarding techniques and we develop end-to-end delay analysis methods for them. Via the analysis methods and applying them to synthetic use cases we show that the intuitive existing approach of encapsulating multiple CAN frames into a single Ethernet frame is not necessarily an efficient solution. In fact, we demonstrate several cases where it is preferable to encapsulate only one CAN frame into a TSN frame, in particular when we use a high speed TSN network. The results have a significant impact on developing such gateways as the implementation of the one-to-one frame encapsulation is considerably simpler than other complex gateway-forwarding techniques.

In this paper, we present an end-to-end timing model to capture timing information from software architectures of distributed embedded systems that use network communication based on the Time-Sensitive Networking (TSN) standards. Such a model is required as an input to perform end-to-end timing analysis of these systems. Furthermore, we present a methodology that aims at automated extraction of instances of the end-to-end timing model from component-based software architectures of the systems and the TSN network configurations. As a proof of concept, we implement the proposed end-to-end timing model and the extraction methodology in the Rubus Component Model (RCM) and its tool chain Rubus-ICE that are used in the vehicle industry. We demonstrate the usability of the proposed model and methodology by modeling a vehicular industrial use case and performing its timing analysis.

There is a growing interest in increasing the flexibility and the mobility of industrial infrastructures to support novel industrial applications. To support this change, industrial networks must provide real-time guarantees while integrating a great variety of traffic over a cohesive network infrastructure. Specifically, there is special interest in the integration of wired and wireless communications in the industrial domain. We present a solution that integrates a Time-Sensitive Networking Ethernet network with a low-power 6TiSCH IoT network and discuss the implementation alternatives and their implications on delay and resource consumption. The main goal is to experimentally identify the research challenges and necessary enhancements for interoperability between constrained battery-driven wireless communication with the time sensitive wired networks.

In this paper, we identify that the existing end-to-end data propagation delay analysis for distributed embedded systems can calculate pessimistic (over-estimated) analysis results when the nodes are synchronized. This is particularly the case of the Scheduled Traffic (ST) class in Time-sensitive Networking (TSN), which is scheduled offline according to the IEEE 802.1Qbv standard and the nodes are synchronized according to the IEEE 802.1AS standard. We present a comprehensive system model for distributed embedded systems that incorporates all of the above mentioned aspect as well as all traffic classes in TSN. We extend the analysis to support both synchronization and non-synchronization among the ECUs as well as offline schedules on the networks. The extended analysis can now be used to analyze all traffic classes in TSN when the nodes are synchronized without introducing any pessimism in the analysis results. We evaluate the proposed model and the extended analysis on a vehicular industrial use case.

Many industrial real-time applications in various domains, e.g., automotive, industrial automation, industrial IoT, and industry 4.0, require ultra-low end-to-end network latency, often in the order of 10 milliseconds or less. The IEEE 802.1 time-sensitive networking (TSN) is a set of standards that supports the required low-latency wired communication with ultra-low jitter. The flexibility of such a wired connection can be increased if it is integrated with a mobile wireless network. The fifth generation of cellular networks (5G) is capable of supporting the required levels of network latency with the Ultra-Reliable Low Latency Communication (URLLC) service. To fully utilize the potential of these two technologies (TSN and 5G) in industrial applications, seamless integration of the TSN wired-based network with the 5G wireless-based network is needed. In this article, we provide a comprehensive and well-structured snapshot of the existing research on TSN-5G integration. In this regard, we present the planning, execution, and analysis results of the systematic review. We also identify the trends, technical characteristics, and potential gaps in the state of the art, thus highlighting future research directions in the integration of TSN and 5G communication technologies. We notice that 73% of the primary studies address the time synchronization in the integration of TSN and 5G technologies, introducing approaches with an accuracy starting from the levels of hundred nanoseconds to one microsecond. Majority of primary studies aim at optimizing communication latency in their approach, which is a key quality attribute in automotive and industrial automation applications today.

In this paper, we present a hierarchical model for time predictable task scheduling in edge-cloud computing architecture for industrial cyber-physical systems. Regarding the scheduling problem, we also investigate the common problem-solving approaches and discuss our preliminary plan to realize the proposed architecture. Furthermore, an Integer linear programming (ILP) model is proposed for task scheduling problem in the cloud layer. The model considers timing and security requirements of applications and the objective is to minimize the financial cost of their execution.

The paper presents an approach to solve the software and hardware related failures in edge-cloud environments, more precisely, in cloud manufacturing environments. The proposed approach, called TOLERANCER, is composed of distributed components that continuously interact in a peer to peer fashion. Such interaction aims to detect stress situations or node failures, and accordingly, TOLERANCER makes decisions to avoid or solve any potential system failures. The efficacy of the proposed approach is validated through a set of experiments, and the performance evaluation shows that it responds effectively to different faults scenarios.

Novel industrial applications are leading to important changes in industrial systems. One of the most important changes is the need for systems that are capable to adapt to changes in the environment or the system itself. Because of their nature many of these applications are distributed, and their network infrastructure is key to guarantee the correct operation of the overall system. Furthermore, in order for a distributed system to be able to adapt, its network must be flexible enough to support changes in the traffic during runtime. The Time-Sensitive Networking (TSN) Task Group has proposed a series of standards that aim at providing deterministic real-time communications over Ethernet. TSN also provides centralised online configuration and control architectures which enable the online configuration of the network. A key part in TSN’s centralised architectures is the Centralised Network Configuration element (CNC). In this work we present a first implementation of a CNC capable of scheduling time-triggered traffic and deploying such configuration in the network using the Network Configuration (NETCONF) protocol. We also assess the correctness of our implementation using an industrial use case provided by Volvo Construction Equipment.

In this paper, we present our ongoing work on proposing solutions to integrate legacy end-stations into Time-Sensitive Network (TSN) communication systems where the legacy end-stations are synchronized via their legacy clock synchronization protocol. To this end, we experimentally identify the effects of lacking synchronization or partial synchronization in TSN networks. In the experiments we show the effects of clock synchronization in different scenarios on jitter and clock drifts. Based on the experiments, we propose preliminary solutions to overcome the identified effects.

Ongoing changes in industrial automation aim to-wards a flat and highly interconnected architecture that includes end-to-end real-time enabled machine-to-machine communications. Several technologies, such as OPC Unified Architecture (OPC UA) publish-subscribe and time-sensitive networking (TSN), facilitate that change. While OPC UA PubSub and TSN can already provide real-time capabilities, the parallel operation with standard OPC UA client-server remains an open challenge. This article presents preliminary results for solving concurrent information model access between OPC UA PubSub and client-server. The results include the overall RT-TSN-OPC UA concept, an analysis of common concurrent data access mechanisms for their suitability, and identifying critical code segments in the open62541 OPC UA stack. The paper concludes by outlining further research focusing on implementing and evaluating a wait-and obstruction-free mechanism into open62541.

Wireless sensor and actuator networks (WSAN) are real-time systems which demand timing requirements. To ensure this level of requirements, different timing analysis approaches have been proposed for WSAN systems. Among different alternatives, analytical analysis and model checking approaches are two common ones which are widely used for the timing analysis of WSAN systems. Analytical approaches apply worst-case response time analysis techniques, whereas model checking generates explicit states of models to analyze them. In this paper, we develop schedulability analysis techniques based on two approaches, i.e., analytical and model checking approaches. We apply and compare the proposed analysis approaches on WSAN systems with an application in monitoring and control of civil infrastructures implemented on the Imote2 wireless sensor platform. We show that the highest possible data acquisition frequency for this application is computed while meeting the deadlines, and compare the results of the two approaches in terms of scalability, extensibility, and flexibility.

The integration of Time-Sensitive Networks (TSN) with 5G cellular networks requires a defined architecture for network configuration and management. Although 3GPP specifications provide necessary means for the TSN-5G integration, the operation of such converged TSN-5G network remains an open challenge for the research community. To address this challenge, this paper presents the ongoing work in developing a centralized architectural model to configure the TSN-5G network, and forward traffic from TSN to 5G and vice-versa. The proposed architectural model uses knowledge of the traffic characteristics to carry out a more accurate mapping of quality of service attributes between TSN and 5G.

Extraction of end-to-end timing information from software architectures of vehicular systems to support their timing analysis is a daunting challenge. To address this challenge, this paper presents a systematic method to extract this information from vehicular software architectures that can be distributed over several electronic control units connected by Time-Sensitive Networking (TSN) networks. As a proof of concept, the proposed extraction method is applied to an industrial component model, namely the Rubus Component Model (RCM), and its toolchain. Furthermore, the usability of the proposed method is demonstrated in an industrial use case from the vehicular domain.

Integrating wired Ethernet networks, such as Time-Sensitive Networks (TSN), to 5G cellular network requires a flow management technique to efficiently map TSN traffic to 5G Quality-of-Service (QoS) flows. The 3GPP Release 16 provides a set of predefined QoS characteristics, such as priority level, packet delay budget, and maximum data burst volume, which can be used for the 5G QoS flows. Within this context, mapping TSN traffic flows to 5G QoS flows in an integrated TSN-5G network is of paramount importance as the mapping can significantly impact on the end-to-end QoS in the integrated network. In this paper, we present a novel and efficient mapping algorithm to map different TSN traffic flows to 5G QoS flows. To the best of our knowledge, this is the first QoS-aware mapping algorithm based on the application constraints used to exchange flows between TSN and 5G network domains. We evaluate the proposed mapping algorithm on synthetic scenarios with random sets of constraints on deadline, jitter, bandwidth, and packet loss rate. The evaluation results show that the proposed mapping algorithm can fulfill over 90% of the applications’ constraints.

Time Sensitive Networking (TSN) is a set of IEEE standards based on switched Ethernet that aim at meeting high-bandwidth and low-latency requirements in wired communication. TSN implementations typically do not support integration of wireless networks, which limits their applicability to many industrial applications that need both wired and wire-less communication. The development of 5G and its promised Ultra-Reliable and Low-Latency Communication (URLLC) in-tegrated with TSN would offer a promising solution to meet the bandwidth, latency and reliability requirements in these industrial applications. In order to support such an integration, we propose a technique to translate the traffic between TSN and 5G communication technologies. As a proof of concept, we implement the translation technique in a well-known TSN simulator, namely NeSTiNg, that is based on the OMNeT ++ tool. Furthermore, we evaluate the proposed technique using an automotive industrial use case.

This paper addresses the scheduling of industrial time-critical applications on multi-core embedded systems. A novel scheduling technique under partitioned scheduling is proposed that minimizes inter-core data-propagation delays between tasks that are activated with different periods. The proposed technique is based on the read-execute-write model for the execution of tasks to guarantee temporal isolation when accessing the shared resources. A Constraint Programming formulation is presented to find the schedule for each core. Evaluations are preformed to assess the scalability as well as the resulting schedulability ratio, which is still 18% for two cores that are both utilized 90%. Furthermore, an automotive industrial case study is performed to demonstrate the applicability of the proposed technique to industrial systems. The case study also presents a comparative evaluation of the schedules generated by (i) the proposed technique and (ii) the Rubus-ICE industrial tool suite with respect to jitter, inter-core data-propagation delays and their impact on data age of task chains that span multiple cores.

This paper presents a schedulability analysis for the Best-Effort (BE) traffic class within Time Sensitive Networking (TSN) networks. The presented analysis considers several features in the TSN standards, including the Credit-Based Shaper (CBS), the Time-Aware Shaper (TAS) and the frame preemption. Although the BE class in TSN is primarily used for the traffic with no strict timing requirements, some industrial applications prefer to utilize this class for the non-hard real-time traffic instead of classes that use the CBS. The reason mainly lies in the fact that the complexity of TSN configuration becomes significantly high when the time-triggered traffic via the TAS and other classes via the CBS are used altogether. We demonstrate the applicability of the presented analysis on a vehicular application use case. We show that a network designer can get information on the schedulability of the BE traffic, based on which the network configuration can be further refined with respect to the application requirements.

This paper proposes a method to efficiently map the legacy Ethernet-based traffic into Time Sensitive Networking (TSN) traffic classes considering different traffic characteristics. Traffic mapping is one of the essential steps for industries to gradually move towards TSN, which in turn significantly mitigates the management complexity of industrial communication systems. In this paper, we first identify the legacy Ethernet traffic characteristics and properties. Based on the legacy traffic characteristics we presented a mapping methodology to map them into different TSN traffic classes. We implemented the mapping method as a tool, named Legacy Ethernet-based Traffic Mapping Tool or LETRA, together with a TSN traffic scheduling and performed a set of evaluations on different synthetic networks. The results show that the proposed mapping method obtains up to 90% improvement in the schedulability ratio of the traffic compared to an intuitive mapping method on a multi-switch network architecture.

Fog and edge computing offer the flexibility and decentralized architecture benefits of cloud computing without suffering from the latency issues inherent in the cloud. This makes fog computing very attractive in real-time and safety-critical applications, especially if combined with container-based technologies. Whereas different orchestration systems are available to manage the container placement based on their resource demand, no orchestration system is considering real-time requirements for containerized applications. In this paper, we present the architecture and design of a real-time container orchestrator based on Kubernetes. Moreover, this paper defines metrics for the performance evaluation of real-time containers, and describes an initial model for allocating a mixture of real-time and non-real-time containers. We present an initial implementation of our real-time container extension and evaluate its feasibility on Linux-based systems.

The functionality advancements and novel customer features that are currently found in modern automotive systems require high-bandwidth and low-latency in-vehicle communications, which become even more compelling for autonomous vehicles. In a recent effort to meet these requirements, the IEEE Time-Sensitive Networking (TSN) task group has developed a set of standards that introduce novel features in Switched Ethernet. TSN standards offer, for example, a common notion of time through accurate and reliable clock synchronization, delay bounds for real-time traffic, time-driven transmissions, improved reliability, and much more. In order to fully utilize the potential of these novel protocols in the automotive domain, TSN should be seamlessly integrated into the state-of-the-art and state-of-practice model-based development processes for automotive embedded systems. Some of the core phases in these processes include software architecture modeling, timing predictability verification, simulation, and hardware realization and deployment. Moreover, throughout the development of automotive embedded systems, the safety and security requirements specified on these systems need to be duly taken into account. In this context, this work provides an overview of TSN in automotive applications and discusses the recent technological developments relevant to the adoption of TSN in automotive embedded systems. The work also points at the open challenges and future research directions.

This paper identifies a limitation in the frame preemption model in the TSN standard (IEEE 802.1Q-2018), due to which high priority frames can experience significantly long blocking delays, thereby exacerbating their worst-case response times. This limitation can have a considerable impact on the design, analysis and performance of TSN-based systems. To address this limitation, the paper presents a novel and more efficient frame preemption model in the TSN standard that allows over 90% reduction in the maximum blocking delay leading to lower worst-case response times of high priority frames compared to the frame preemption model used in the existing works. The paper also shows that the improvement becomes even more significant in multi-switch TSN networks. In order to evaluate the effects of preemption, the paper performs simulations by enabling and disabling preemptions as well as enabling and disabling the Hold/Release mechanism supported by TSN. Furthermore, the paper performs a comparative evaluation of the two models of frame preemption in TSN using simulations. The evaluation shows that the maximum response times of high priority frames can be significantly reduced with very small impact on the response times of lower priority frames. The paper also shows the improvement in the maximum response times of higher priority frames using an automotive industrial use case that employs a multi-hop TSN network for on-board communication.

Large complex industrial Distributed Control Systems (DCS), e.g., power distribution systems, are expected to function for long time, up to 40 years. Therefore, besides having a long system verification phase for all subsystems, the design phase should consider various aspects when it comes to selection of which technologies to utilize when implementing such systems. In this paper, we study and investigate key challenges of using the Time Sensitive Networking (TSN) technology when it comes to design, maintenance and evolution of long life-span complex DCS. We also identify issues and challenges, and propose mitigation strategies for using the TSN technology in long-life system design. Our investigation and analysis shows that many of the TSN standards are in their evolution phase and may as a consequence be subject to different interpretations and implementations. Therefore, achieving a full capacity of using the TSN technology may not be possible, in particular when it comes to design of systems having an expected long life.

Moving towards new technologies, such as Time Sensitive Networking (TSN), in industries should be gradual with a proper integration process instead of replacing the existing ones to make it beneficial in terms of cost and performance. Within this context, this paper identifies the challenges of integrating a legacy EtherCAT network, as a commonly used technology in the automation domain, into a TSN network. We show that clock synchronization plays an essential role when it comes to EtherCAT-TSN network integration with important requirements. We propose a clock synchronization mechanism based on the TSN standards to obtain a precise synchronization among EtherCAT nodes, resulting to an efficient data transmission. Based on a formal verification framework using UPPAAL tool we show that the integrated EtherCAT-TSN network with the proposed clock synchronization mechanism achieves at least 3 times higher synchronization precision compared to not using any synchronization.

With development of cloud computing new ways for easy, on-demand, Internet-based access to computing resources have emerged. In such context a Service Level Agreement (SLA) enables contractual agre ...

This paper presents the first holistic modeling approach for Time-Sensitive Networking (TSN) communication that integrates into a model-and component-based software development framework for distributed embedded systems. Based on these new models, we also present an end-to-end timing model for TSN-interconnected distributed embedded systems. Our approach is expressive enough to model the timing information of TSN and the timing behaviour of software that communicates over TSN, hence allowing end-to-end timing analysis. A proof of concept for the proposed approach is provided by implementing it for a component model and tool suite used in the vehicle industry. Moreover, a use case from the vehicle industry is modeled and analyzed with the proposed approach to demonstrate its usability.

In this paper we address a network architecture that uses a combination of network virtualization and software defined networking in order to reduce complexity of network management and at the same time support high quality of service. Within this network architecture, we propose a framework to be able to dynamically distribute the network bandwidth to various services such that the network resources are utilized efficiently. In many industrial domains, multiple services may use the same hardware platform for the sake of a better resource utilization. Therefore, bandwidth distribution among the services should be done in an efficient way during runtime. We also develop an admission control in this framework which dynamically coordinates the bandwidth distributions based on requested quality of services. We show the applicability of the proposed framework by implementing it on a common SDN controller. Moreover, we conduct a set of experiments to show the performance of the proposed framework.

Future industrial networks are envisioned to support a broad set of applications and services with diverse communication requirements that are difficult to meet adopting a single communication technology. Software-Defined Networking and network virtualization techniques represent two promising innovations and abstractions to improve the network management and to support scalable network control functions, flexible resource allocation, and changes in the network traffic.This paper draws a research direction towards software-defined management of heterogeneous Industry 4.0 communication networks, proposing a software-defined architecture that is able to support a multitude of diverse wired and wireless communication technologies, while meeting the requirements of diverse applications. The paper also provides an implementation roadmap, discussing how to extend the EmPOWER framework to fulfill the intended target, pointing at design challenges and solutions.

This paper investigates the effects of various parameters of high priority traffic classes on the Best Effort (BE) traffic in the networks based on the IEEE Time Sensitive Networking (TSN) standards. In this regard, the paper discusses ongoing work and presents preliminary results using a TSN simulator. The results indicate that several parameters of the high priority traffic such as periods, offsets and preemption modes can have a significant impact on the quality of service (e.g., guaranteed message delivery and message delays) of the BE traffic.

This paper focuses on Service Level Agreements (SLAs) for industrial applications that aim to port some of the control functionalities to the cloud. In such applications, industrial requirements should be reflected in SLAs. In this paper, we present an approach to integrate safety-related aspects of an industrial application to SLAs. We also present the approach in a use case. This is an initial attempt to enrich SLAs for industrial settings to consider safety aspects, which has not been investigated thoroughly before.

With envisioned increased density and complexity of future industrial networks, software defined networking (SDN) and network virtualization are considered to be promising techniques for network organization and management. Thus, in this paper we look at heterogeneous software defined networks consisting of several virtual slices and present a bandwidth control algorithm, which is designed to provide control over shared bandwidth both in wired and wireless parts of the network. The designed algorithm has been implemented in real hardware and in this paper we present the initial test results.

In this paper we evaluate solutions that provide measurements for the network convergence time in switched Ethernet networks when links failures happen. We evaluate three solutions to measure the network convergence time in a faulty situation. Compared to the commercially available solutions, our proposals are cost-effective, portable, and open source. Thus, they are easy to deploy on many testbeds. We show the performance of the solutions by measuring different metrics including jitter, network convergence time and packet loss during the network recovery time. Our measurements indicate that it is possible to accurately measure the network convergence time using a packet sender which does not suffer interference from the overlying operating system. Furthermore, we noticed that the packet sniffer TShark did not suffer from kernel interrupts from overlying operating systems.

Ethernet is a promising candidate for networking real-time embedded systems such as automobiles, and it is already used in several embedded scopes, such as airplanes and trains. Moreover, its higher bandwidth enables applications made of dispersed embedded systems that exchange large amounts of data through the so-called Internet-of-Things, such as wide-area video sensing. In this realm, network reservations are an important design element that favor composability in the time domain thereby supporting the design of complex systems. However, reservations may impact negatively on the network bandwidth efficiency due to over-specification, particularly when they are designed to meet worst-case delay constraints. In this work, we use a specific Ethernet protocol that provides real-time reservations, namely FTT-SE, and we assess through extensive simulations the efficiency of a worst-case network delay analysis for sporadic reservations associated to asynchronous messages. Essentially, we compare the analytical worst-case delay with the one observed in the simulations using two data sets comprising up to 20000 and 100000 message sets, respectively, and we change the system configuration, namely properties of the message sets and network and protocol configuration parameters. We find that the analysis is accurate, i.e. matches observations, for a significant percentage of messages in the message sets (up to 60% on average). Conversely, we found that a small percentage of message sets (below 6%) generated rather pessimistic analytic estimates exceeding the observations by 6 times, thus with a negative impact on efficiency. The results we present in the paper, particularly their distributions, inform system designers of how to tune their designs to improve network bandwidth efficiency under strict timing constraints.

This paper proposes an approach to model switched Ethernet communication within a model- and component-based software development framework for vehicular distributed embedded systems. The paper also presents a method to extract the network timing model from the systems that use switched Ethernet networks. In order to provide a proof of concept, an existing industrial component model and its tool suite, namely RCM and Rubus-ICE respectively, are extended by implementing the modeling technique, the timing model extraction method and response-time analysis of the Ethernet AVB protocol. The extensions to RCM are backward compatible with the modeling and end-to-end timing analysis of traditional in-vehicle networks and legacy (previously developed) vehicular distributed embedded systems. Furthermore, the paper discusses the implementation and test strategy used in this work. Finally, the usability of the modeling approach and implemented timing analysis is demonstrated by modeling and time analyzing a vehicular application case study with the extended component model and tool suite.

Contemporary distributed embedded systems in many domains have become highly complex due to ever-increasing demand on advanced computer controlled functionality. The resource reservation techniques can be effective in lowering the software complexity, ensuring predictability and allowing flexibility during the development and execution of these systems. This paper proposes a novel end-to-end resource reservation model for distributed embedded systems. In order to support the development of predictable systems using the proposed model, the paper provides a method to design resource reservations and an end-to-end timing analysis. The reservation design can be subjected to different optimization criteria with respect to runtime footprint, overhead or performance. The paper also presents and evaluates a case study to show the usability of the proposed model, reservation design method and end-to-end timing analysis.

The IEEE Audio Video Bridging (AVB) technology is nowadays under consideration in several automation domains, such as, automotive, avionics, and industrial communications. AVB offers several benefits, such as open specifications, the existence of multiple providers of electronic components, and the real-time support, as AVB provides bounded latency to real-time traffic classes. In addition to the above mentioned properties, in the automotive domain, comparing with the existing in-vehicle networks, AVB offers significant advantages in terms of high bandwidth, significant reduction of cabling costs, thickness and weight, while meeting the challenging EMC/EMI requirements. Recently, an improvement of the AVB protocol, called the AVB ST, was proposed in the literature, which allows for supporting scheduled traffic, i.e., a class of time-sensitive traffic that requires time-driven transmission and low latency. In this paper, we present a schedulability analysis for the real-time traffic crossing through the AVB ST network. In addition, we formally prove that, if the bandwidth in the network is allocated according to the AVB standard, the schedulability test based on response time analysis will fail for most cases even if, in reality, these cases are schedulable. In order to provide guarantees based on analysis test a bandwidth over-reservation is required. In this paper, we propose a solution to obtain a minimized bandwidth over-reservation. To the best of our knowledge, this is the first attempt to formally spot the limitation and to propose a solution for overcoming it. The proposed analysis is applied to both the AVB standard and the AVB ST. The analysis results are compared with the results of several simulative assessments, obtained using OMNeT++, on both automotive and industrial case studies. The comparison between the results of the analysis and the simulation ones shows the effectiveness of the analysis proposed in this work.

There is a plethora of models, techniques and tools that support model-and component-based software development of vehicular distributed embedded systems. However, a large majority of them have a limited or no support to model and specify end-to-end resource reservations on the software architectures of these systems. Resource reservations allow flexibility during the development and execution of such complex systems without jeopardizing their predictable behavior. As a result, several applications in the system that share the same hardware platform can be developed independently. In this paper we identify several requirements that any existing component model should fulfill in order to support the modeling of end-to-end resource reservations on the software architectures of such systems. As a proof of concept, we extend the Rubus Component Model (RCM) by fulfilling these requirements. RCM is used for the development of control functionality in vehicular embedded systems by several international companies. We also provide a technique to extract execution models from the software architectures of these systems with resource reservations. In order to show the usability of our technique, we model a vehicular distributed embedded system with the extended component model and extract the execution model from the software architecture augmented with end-to-end resource reservations.

The resource reservation techniques provide effective means to lower the software complexity, ensure predictability and allow flexibility during the development and execution of complex distributed embedded systems. In this paper we propose a new end-to-end resource reservation model for distributed embedded systems. The model is comprehensive in such a way that it supports end-to-end resource reservations on distributed transactions with various activation patterns that are commonly used in industrial control systems. The model allows resource reservations on processors and real-time network protocols. We also present timing analysis for the distributed embedded systems that are developed using the proposed model. The timing analysis computes the end-to-end response times as well as delays such as data age and reaction delays. The presented analysis also supports real-time networks that can autonomously initiate transmissions. Such networks are not supported by the existing analyses. We also include a case study to show the usability of the model and end-to-end timing analysis with resource reservations.

The ability of reconfiguring a system during runtime is essential for dynamic real-time applications in which resource usage is traded online for quality of service. The HaRTES switch, which is a modified Ethernet switch, holds this ability for the network resource, and at the same time it provides hard real-time support for both periodic and sporadic traffic. Although the HaRTES switch technologically caters this ability, a protocol to actually perform the dynamic reconfiguration is missing in multi-hop HaRTES networks. In this paper we introduce such a protocol that is compatible with the traffic scheduling method used in the architecture. We prove the correctness of the protocol using a model checking technique. Moreover, we conduct a set of simulation experiments to show the performance of the protocol and we also show that the reconfiguration process is terminated within a bounded time.

In this paper we discuss the challenges that are faced when the state-of-the-art research results are transferred to a model-based tool chain for the industrial use. These challenges are often overlooked when the research results are implemented in an academic environment. In particular, we discuss various challenges regarding the implementation and integration of the response-time analysis for heterogeneous networks, comprising of CAN and Ethernet AVB, as a plug-in for the Rubus Analysis Framework. Rubus tool suite is used for the model- and component-based development of software for vehicular real-time systems by several international companies. We also discuss preliminary solutions to deal with the challenges.

On-the-fly adaptability and reconfigurability are recently becoming an interest in real-time communications. To assure a continued real-time behavior, the admission control with a quality-of-service mechanism is required, that screen all adaptation and reconfiguration requests. In the context of switched Ethernet networks, the FTT-SE protocol provides adaptive real-time communication. Recently, we proposed two methods to perform the online reconfiguration in multi-hop FTT-SE architectures. However, the methods lack the experimental evaluation. In this paper, we evaluate both methods in terms of the reconfiguration time.

In the context of switched Ethernet networks, multi-hop communication is essential as the networks in industrial applications comprise a high amount of nodes, that is far beyond the capability of a single switch. In this paper, we focus on multi-hop communication using HaRTES switches. The HaRTES switch is a modified Ethernet switch that provides real-time traffic scheduling, dynamic Quality-of-Service and temporal isolation between real-time and non-real-time traffic. Herein, we propose a method, called Reduced Buffering Scheme, to conduct the traffic through multiple HaRTES switches in a multi-hop HaRTES architecture. In order to enable the new scheduling method we propose to modify the HaRTES switch structure. Moreover, we develop a response time analysis for the new method. We also compare the proposed method with a method previously proposed, called Distributed Global Scheduling, based on their traffic response times. We show that, the new method forwards all types of traffic including the highest, the medium and the lowest priority, faster than the previous method in most of the cases. Furthermore, we show that the new method performs even better for larger networks compared with the previous one.

The interest to use Switched Ethernet technologies in real-time communication is increasing due to its absence of collisions when transmitting messages. Nevertheless, using COTS switches affect the timeliness guarantee inherent in potentially overflowing internal FIFO queues. In this paper we focus on a solution, called the FTT-SE protocol, which is developed based on a master-slave technique. Recently, an extension of the FTT-SE protocol has been proposed where the transmission of messages are controlled using multiple master nodes. In order to guarantee the correctness of the protocol, the masters should be timely synchronized. Therefore, in this paper we investigate the possibility of using a clock synchronization protocol, based on the IEEE 1588 standard, among master nodes. Moreover, we evaluate the overhead that is imposed by the clock synchronization protocol to the FTT-SE protocol. Finally, we present a formal verification of this solution by means of model checking technique to prove the correctness of the FTT-SE protocol when the clock synchronization protocol is applied.