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See detailDeep Learning to Predict the Feasibility of Priority-Based Ethernet Network Configurations
Mai, Tieu Long UL; Navet, Nicolas UL

in ACM Transactions on Cyber-Physical Systems (2021), 5(4), 126

Machine learning has been recently applied in real-time systems to predict whether Ethernet network configurations are feasible in terms of meeting deadline constraints without executing conventional ... [more ▼]

Machine learning has been recently applied in real-time systems to predict whether Ethernet network configurations are feasible in terms of meeting deadline constraints without executing conventional schedulability analysis. However, the existing prediction techniques require domain expertise to choose the relevant input features and do not perform consistently when topologies or traffic patterns differ significantly from the ones in the training data. To overcome these problems, we propose a Graph Neural Network (GNN) prediction model that synthesizes relevant features directly from the raw data. This deep learning model possesses the ability to exploit relations among flows, links, and queues in switched Ethernet networks, and generalizes to unseen topologies and traffic patterns. We also explore the use of ensembles of GNNs and show that it enhances the robustness of the predictions. An evaluation on heterogeneous testing sets comprising realistic automotive networks, shows that ensembles of 32 GNN models features a prediction accuracy ranging from 79.3% to 90% for Ethernet networks using priorities as the Quality-of-Service mechanism. The use of ensemble models provides a speedup factor ranging from 77 to 1715 compared to schedulability analysis, which allows a far more extensive design space exploration. [less ▲]

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See detailDo We Really Need TSN in Next-Generation Helicopters? Insights From a Case-Study
Mauclair, Cédric; Gutiérrez, Marina; Migge, Jörn et al

in 2021 AIAA/IEEE 40th Digital Avionics Systems Conference (DASC) (2021, October)

As Ethernet rapidly replaces legacy networks as the core high-speed network in helicopter’s avionics and mission systems, we ask in this paper the question of the technical benefits of migrating to ... [more ▼]

As Ethernet rapidly replaces legacy networks as the core high-speed network in helicopter’s avionics and mission systems, we ask in this paper the question of the technical benefits of migrating to Ethernet Time-Sensitive-Networking (TSN). Indeed, TSN has become a rich toolbox of mechanisms and protocols to address Quality-of-Service (QoS) requirements pertaining to timing and reliability. TSN is quickly becoming the prominent technology for wired high-speed communications in a variety of application domains like automotive, industry 4.0 and telecom. In this context, this work explores the use of TSN timing QoS mechanisms for helicopter’s avionics and mission systems on a case-study representative of the communication requirements of next-generation systems. This study aims to provide quantified insights into what can be expected from TSN in terms of timing, memory usage and extensibility. [less ▲]

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See detailImprovements to Deep-Learning-based Feasibility Prediction of Switched Ethernet Network Configurations
Mai, Tieu Long UL; Navet, Nicolas UL

in The 29th International Conference on Real-Time Networks and Systems (RTNS2021) (2021, April 07)

Graph neural network (GNN) is an advanced machine learning model, which has been recently applied to encode Ethernet configurations as graphs and predict their feasibility in terms of meeting deadlines ... [more ▼]

Graph neural network (GNN) is an advanced machine learning model, which has been recently applied to encode Ethernet configurations as graphs and predict their feasibility in terms of meeting deadlines constraints. Ensembles of GNN models have proven to be robust to changes in the topology and traffic patterns with respect to the training set. However, the moderate prediction accuracy of the model, 79.3% at the lowest, hinders the application of GNN to real-world problems. This study proposes improvements to the base GNN model in the construction of the training set and the structure of the model itself. We first introduce new training sets that are more diverse in terms of topologies and traffic patterns and focus on configurations that are difficult to predict. We then enhance the GNN model with more powerful activation functions, multiple channels and implement a technique called global pooling. The prediction accuracy of the ensemble GNN model with a combination of the suggested improvements increases significantly, up to 11.9% on the same 13 testing sets. Importantly, these improvements increase only marginally the time it takes to predict unseen configurations, i.e., the speedup factor is still from 50 to 1125 compared to schedulability analysis, which allows a far more extensive exploration of the design space. [less ▲]

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See detailQoS-Predictable SOA on TSN: Insights from a Case-Study
Villanueva, Josetxo; Migge, Jörn; Navet, Nicolas UL

Scientific Conference (2021, February 09)

This work is about the design and configuration of service-oriented communication on top of Ethernet TSN. The first objective is to present takeaways from the design and implementation of the Renault E/E ... [more ▼]

This work is about the design and configuration of service-oriented communication on top of Ethernet TSN. The first objective is to present takeaways from the design and implementation of the Renault E/E Service-Oriented Architecture (SOA) called FACE. In particular, we discuss technological, design and configuration choices made for the SOA, such as how to segment messages (UDP with multiple events, TCP, SOME/IP TP), and the technical possibilities to shape the transmission of the packets on the Ethernet network. The second objective is to study how to ensure the Quality of Service (QoS) required by services. Indeed, services introduce specific challenges, be it only the sheer amount of traffic they generate and if there is a growing body of experiences in the use of TSN QoS mechanisms most of what has been learned so far is mostly about meeting the requirements of individual streams. Less is known for services that involve the transmission of several, possibly segmented, messages with more complex transmission patterns. We show on the FACE architecture how SOME/IP messages were mapped to TSN QoS mechanisms in a manual then automated manner so as to meet the individual requirements of the services in terms of timing, and the system’s requirements in terms of memory usage. [less ▲]

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See detailPractical Use Cases for Ethernet Redundancy
Pannell, Don; Navet, Nicolas UL

Scientific Conference (2020, September 17)

Autonomous driving requires safety considerations and the need of “fail operational” requires redundancy. In the networking portion of a car, this may mean separate networks, possibly of different ... [more ▼]

Autonomous driving requires safety considerations and the need of “fail operational” requires redundancy. In the networking portion of a car, this may mean separate networks, possibly of different technologies. Or it could mean a network topology and technology that supports scalable redundancy, like Ethernet TSN. This presentation focuses on IEEE 802.1CB-2017, which is the TSN standard that supports data redundancy through the network. Various network topologies are examined. The relative costs of adding TSN redundancy for these topologies (including some, or all of, the end-stations/ECUs & bridges) are examined for various bandwidth utilizations, along with the expected packet loss. Each topology and bandwidth will be modeled under various bit-rate error values with the results discussed. This presentation aims at providing a clear understanding of the TSN standards that support redundancy, and an understanding of the cost/benefit tradeoffs so proper engineering decisions can be made and proper expectations set. [less ▲]

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See detailTowards Computer-Aided, Iterative TSN-and Ethernet-based E/E Architecture Design
Creighton, Oliver; Navet, Nicolas UL; Keller, Patrick UL et al

Scientific Conference (2020, September 16)

In this presentation we would like to propose a novel approach towards studying and simulating candidate designs of next generation Ethernet architectures at established OEMs that intend to employ 100BASE ... [more ▼]

In this presentation we would like to propose a novel approach towards studying and simulating candidate designs of next generation Ethernet architectures at established OEMs that intend to employ 100BASE-T1, 1000BASE-T1 and, for increased flexibility and lower cost, 10BASE-T1S. Typical design goals of next generation architectures are future extensibility and cost optimization of the lowest-end. We propose to introduce guidance to an otherwise standard Monte-Carlo simulation by providing certain fixed points (e.g., mandated connections of ECUs to certain bridges, complete re-use of ECUs) and “hot spots” in the topology (e.g., ECUs with the highest variability pressure) that are known in advance from BMW’s experience with their vehicles in the field. Several important practical considerations must be integrated in the generation of candidate architectures: - Topological constraints: ECU proximity to sensors, daisy chain connections between ECUs to minimize cable length, number of switch ports in a certain ECU, etc. - Security and reliability requirements: segregation between mixed-criticality streams, proxy ECUs, and redundant paths. Our position statement explores the ability of algorithmic tools to synthesize Ethernet-based architectures based on a minimal fixed core TSN topology, design goals, design constraints, assumptions about next generation applications and data from past projects (capturing part of the OEM domain knowledge). [less ▲]

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See detailAutomated Fault Tolerance Augmentation in Model-Driven Engineering for CPS
Hu, Tingting UL; Cibrario Bertolotti, Ivan; Navet, Nicolas UL et al

in Computer Standards and Interfaces (2020), 70

Cyber-Physical Systems are usually subject to dependability requirements such as safety and reliability constraints. Over the last 50 years, a body of efficient fault-tolerance mechanisms has been devised ... [more ▼]

Cyber-Physical Systems are usually subject to dependability requirements such as safety and reliability constraints. Over the last 50 years, a body of efficient fault-tolerance mechanisms has been devised to handle faults occurring at run-time. However, properly implementing those mechanisms is a time-consuming task that requires a great deal of know-how. In this paper, we propose a general framework which allows system designers to decouple functional and non-functional concerns, and express non- functional properties at design time using domain-specific languages. In the spirit of generative programming, functional models are then automatically “augmented” with dependability mechanisms. Importantly, the real-time behavior of the initial models in terms of sampling times and meeting deadlines is preserved. The practicality of the approach is demonstrated with the automated implementation of one prominent software fault-tolerance pattern, namely N-Version Programming, in the CPAL model-driven engineering workflow. [less ▲]

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See detailEarly-stage Bottleneck Identification and Removal in TSN Networks
Navet, Nicolas UL; Bengtsson, Hoai Hoang; Migge, Jörn

Scientific Conference (2020, February 12)

There has been a pivotal change in the design of E/E architectures, which is that OEM cannot assume anymore that the functions, and thus the communication requirements, are known in advance and fixed over ... [more ▼]

There has been a pivotal change in the design of E/E architectures, which is that OEM cannot assume anymore that the functions, and thus the communication requirements, are known in advance and fixed over time. It has become crucial for OEMs to be in the position to add further functions and services during the lifetime of the vehicle: OEMs need to design E/E architectures that are future-proof. We propose design space exploration algorithms, which, by answering a series of design questions and proposing solutions to the designers, help to improve an automotive E/E architecture in several dimensions: performance, costs, reliability and extensibility. We start by estimating the total "capacity" of a baseline architecture, then, by removing bottlenecks, we obtain an "enhanced capacity" architecture, which is then optimized in terms of costs and reliability. The architecture is then further optimized in terms of costs and reliability. The work is conducted on Volvo's prototype centralized and domain-based E/E architecture. [less ▲]

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See detailEvent Notification in CAN-based Sensor Networks
Bloom, Gedare; Cena, Gianluca; Cibrario Bertolotti, Ivan et al

in IEEE Transactions on Industrial Informatics (2019), 15(10), 5613-5625

Preventive and reactive maintenance require the collection of an ever-increasing amount of information from industrial plants and other complex systems, like those based on robotized cells, a need that ... [more ▼]

Preventive and reactive maintenance require the collection of an ever-increasing amount of information from industrial plants and other complex systems, like those based on robotized cells, a need that can be fulfilled by means of a suitable event notification mechanism. At the same time, timing and delivery reliability requirements in those scenarios are typically less demanding than in other cases, thus enabling the adoption of best-effort notification approaches. This paper presents, evaluates, and compares some of those approaches, based on either standard CAN messaging or a recently proposed protocol extension called CAN XR. In the second case, the combined use of Bloom filters is also envisaged to increase flexibility. Results show that the latter approaches are advantageous in a range of event generation rates and network topologies of practical relevance. [less ▲]

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See detailEarly-stage topological and technological choices for TSN-based communication architectures
Navet, Nicolas UL; Villanueva, Josetxo; Migge, Jörn

Scientific Conference (2019, September 24)

A main issue in the design of automotive communication architectures is that the most important design choices pertaining to the topology of the networks and the technologies to use (protocols, data rate ... [more ▼]

A main issue in the design of automotive communication architectures is that the most important design choices pertaining to the topology of the networks and the technologies to use (protocols, data rate, hardware) have to be made at a time when the communication requirements are not entirely known. Indeed, many functions only becomes available along the development cycle, and vehicle platforms have to support incremental evolutions of the embedded system that may not be fully foreseeable at the time design choices are made. The problem is becoming even more difficult and crucial with the introduction of dynamically evolving communication requirements requiring network re-configuration at run-time. We present how the use of synthetic data, that is data generated programmatically based on past vehicle projects and what can be foreseen for the current project, enables the designers to make such early stage choices based on quantified metrics. The proposals are applied to Groupe Renault's FACE service-oriented E/E architecture with the use of a software-implemented function we called “Topology Stress Test”. [less ▲]

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See detailA Hybrid Machine Learning and Schedulability Method for the Verification of TSN Networks
Mai, Tieu Long UL; Navet, Nicolas UL; Migge, Jörn

in 15th IEEE International Workshop on Factory Communication Systems (WFCS2019) (2019, March)

Machine learning (ML), and supervised learning in particular, can be used to learn what makes it hard for a network to be feasible and try to predict whether a network configuration will be feasible ... [more ▼]

Machine learning (ML), and supervised learning in particular, can be used to learn what makes it hard for a network to be feasible and try to predict whether a network configuration will be feasible without executing a conventional schedulability analysis. A disadvantage of ML-based timing verification with respect to schedulability analysis is the possibility of "false positives": configurations deemed feasible while they are not. In this work, in order to minimize the rate of false positives, we propose the use of a measure of the uncertainty of the prediction to drop it when the uncertainty is too high, and rely instead on schedulability analysis. In this hybrid verification strategy, the clear-cut decisions are taken by ML, while the more difficult ones are taken by a conventional schedulability analysis. Importantly, the trade-off achieved between prediction accuracy and computing time can be controlled. We apply this hybrid verification method to Ethernet TSN networks and obtain, for instance in the case of priority scheduling with 8 traffic classes, a 99% prediction accuracy with a speedup factor of 5.7 with respect to conventional schedulability analysis and a reduction of 46% of the false positives compared to ML alone. [less ▲]

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See detailUsing Machine Learning to Speed Up the Design Space Exploration of Ethernet TSN networks
Navet, Nicolas UL; Mai, Tieu Long UL; Migge, Jörn

Report (2019)

In this work, we ask if Machine Learning (ML) can provide a viable alternative to conventional schedulability analysis to determine whether a real-time Ethernet network meets a set of timing constraints ... [more ▼]

In this work, we ask if Machine Learning (ML) can provide a viable alternative to conventional schedulability analysis to determine whether a real-time Ethernet network meets a set of timing constraints. Otherwise said, can an algorithm learn what makes it difficult for a system to be feasible and predict whether a configuration will be feasible without executing a schedulability analysis? In this study, we apply standard supervised and unsupervised ML techniques and compare them, in terms of their accuracy and running times, with precise and approximate schedulability analyses in Network-Calculus. We show that ML techniques are efficient at predicting the feasibility of realistic TSN networks and offer new trade-offs between accuracy and computation time especially interesting for design-space exploration algorithms. [less ▲]

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See detailOn the use of supervised machine learning for assessing schedulability: application to Ethernet TSN
Mai, Tieu Long UL; Navet, Nicolas UL; Migge, Jörn

in 27th International Conference on Real-Time Networks and Systems (RTNS 2019) (2019)

In this work, we ask if Machine Learning (ML) can provide a viable alternative to conventional schedulability analysis to determine whether a real-time Ethernet network meets a set of timing constraints ... [more ▼]

In this work, we ask if Machine Learning (ML) can provide a viable alternative to conventional schedulability analysis to determine whether a real-time Ethernet network meets a set of timing constraints. Otherwise said, can an algorithm learn what makes it difficult for a system to be feasible and predict whether a configuration will be feasible without executing a schedulability analysis? To get insights into this question, we apply a standard supervised ML technique, k-nearest neighbors (k-NN), and compare its accuracy and running times against precise and approximate schedulability analyses developed in Network-Calculus. The experiments consider different TSN scheduling solutions based on priority levels combined for one of them with traffic shaping. The results obtained on an automotive network topology suggest that k-NN is efficient at predicting the feasibility of realistic TSN networks, with an accuracy ranging from 91.8% to 95.9% depending on the exact TSN scheduling mechanism and a speedup of 190 over schedulability analysis for 10^6 configurations. Unlike schedulability analysis, ML leads however to a certain rate "false positives'' (i.e., configurations deemed feasible while they are not). Nonetheless ML-based feasibility assessment techniques offer new trade-offs between accuracy and computation time that are especially interesting in contexts such as design-space exploration where false positives can be tolerated during the exploration process. [less ▲]

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Peer Reviewed
See detailInsights into the performance and configuration of TCP in Automotive Ethernet Networks
Navet, Nicolas UL; Migge, Jörn

Scientific Conference (2018, October 10)

TCP has become an integral part of the Autosar communication stack located immediately below the Socket Adaptor layer. There are numerous use-cases for TCP in automotive networks. First TCP can be ... [more ▼]

TCP has become an integral part of the Autosar communication stack located immediately below the Socket Adaptor layer. There are numerous use-cases for TCP in automotive networks. First TCP can be leveraged on by many higher-level protocols be it for diagnostic (DoIp), calibration protocols (XCP), service-oriented communications (SomeIP), FTP and HTTP transfer, or more specialized tasks like protocols for the control of electric vehicle charging. In addition, communication through standard TCP sockets simplifies the development and re-use of applications requiring reliable transmissions within the vehicle or with external end-systems (car2x, cloud-based services).If previous works focused on throughput as performance criterion, we here also consider the communication latencies and memory usage in the end-systems and switches. The first question explored by simulation is to quantify the importance of TCP configuration choices in the latencies that can be achieved with TCP. In particular, it is shown that turning off Nagle's algorithm in transmission and delayed acknowledgment in reception as Autosar is very beneficial in terms of latencies but at the expense of throughput. We then extend the experiments to integrate the interactions between the Socket Adaptor and TCP layers. Finally, we study the performance of TCP streams as part of a complete automotive TSN case-study made up of control traffic, audio/video streams and best-effort traffic to evaluate the impact of higher priority traffic classes on TCP streams throughput and delays. The contribution of this work is twofold. First, we draw up a panorama of the TCP features and configuration options available in Autosar. Second, through experiments on models increasingly close to an implementation, we provide quantified insights in what we can expect from TCP in terms of latencies and throughput with the different configuration options available to us. [less ▲]

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See detailA journey into time-triggered communication protocols with a focus on Ethernet TSN
Navet, Nicolas UL

Presentation (2018, June 11)

This presentation provides an historical perspective on time-triggered (TT) protocols and highlights a few possible misconceptions about TT communication. The presentation is organized as follows: 1 ... [more ▼]

This presentation provides an historical perspective on time-triggered (TT) protocols and highlights a few possible misconceptions about TT communication. The presentation is organized as follows: 1) landscape of real-time (wired) communication networks, 2) Time-triggered (TT) protocols evolution: TTP, FlexRay, TTEthernet, TSN/TAS (IEEE802.1Qbv) 3) Misconceptions about TT communication 4) Takeaways and what is ahead of us. [less ▲]

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Peer Reviewed
See detailTowards the Systematic Analysis of Non-Functional Properties in Model-Based Engineering for Real-Time Embedded Systems
Brau, Guillaume UL; Navet, Nicolas UL; Hugues, Jérôme

in Science of Computer Programming (2018), 156

The real-time scheduling theory provides analytical methods to assess the temporal predictability of embedded systems. Nevertheless, their use is limited in a Model-Based Systems Engineering approach. In ... [more ▼]

The real-time scheduling theory provides analytical methods to assess the temporal predictability of embedded systems. Nevertheless, their use is limited in a Model-Based Systems Engineering approach. In fact, the large number of applicability conditions makes the use of real-time scheduling analysis tedious and error-prone. Key issues are left to the engineers: when to apply a real-time scheduling analysis? What to do with the analysis results?} This article presents an approach to systematize and then automate the analysis of non-functional properties in Model-Based Systems Engineering. First, preconditions and postconditions define the applicability of an analysis. In addition, contracts specify the analysis interfaces, thereby enabling to reason about the analysis process. We present a proof-of-concept implementation of our approach using a combination of constraint languages (REAL for run-time analysis) and specification languages (Alloy for describing interfaces and reasoning about them). This approach is experimented on architectural models written with the Architecture Analysis and Design Language (AADL). [less ▲]

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See detailPre-shaping Bursty Transmissions under IEEE802.1Q as a Simple and Efficient QoS Mechanism
Navet, Nicolas UL; Migge, Jörn; Villanueva, Josetxo et al

in Proc. WCX World Congress Experience (2018, April)

The automotive industry is swiftly moving towards Ethernet as the high-speed communication network for in-vehicle communication. There is nonetheless a need for protocols that go beyond what standard ... [more ▼]

The automotive industry is swiftly moving towards Ethernet as the high-speed communication network for in-vehicle communication. There is nonetheless a need for protocols that go beyond what standard Ethernet has to offer in order to provide additional QoS to demanding applications such as ADAS systems or audio/video streaming. The main protocols currently considered for that purpose are IEEE802.1Q, AVB with the Credit Based Shaper mechanism (IEEE802.1Qav) and TSN with its Time-Aware Shaper (IEEE802.1Qbv). AVB/CBS and TSN/TAS both provide efficient QoS mechanisms and they can be used in a combined manner, which offers many possibilities to the designer. Their use however requires dedicated hardware and software components, and clock synchronization in the case of TAS. Previous studies have also shown that the efficiency of these protocols depends much on the application at hand and the value of the configuration parameters. In this work, we explore the use of “pre-shaping” strategies under IEEE802.1Q for bursty traffic such as audio/video streams as a simple and efficient alternative to AVB/CBS and TSN/TAS. Pre-shaping means inserting on the sender side “well-chosen” pauses between successive frames of a transmission burst (e.g., as it happens when sending a camera frame), all the other characteristics of the traffic remaining unchanged. We show on an automotive case-study how the use of pre-shaping for audio/video streams leads to a drastic reduction of the communication latencies for the best-effort streams while enabling to meet the timing constraints for the rest of the traffic. We then discuss the limitations of the pre-shaping mechanism and future works needed to facilitate its adoption. [less ▲]

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See detailA Model-Driven Co-Design Framework for Fusing Control and Scheduling Viewpoints
Sundharam, Sakthivel Manikandan UL; Navet, Nicolas UL; Altmeyer, Sebastian et al

in Sensors (2018), 18(2), 628

Model-Driven Engineering (MDE) is widely applied in the industry to develop new software functions and integrate them into the existing run-time environment of a Cyber-Physical System (CPS). The design of ... [more ▼]

Model-Driven Engineering (MDE) is widely applied in the industry to develop new software functions and integrate them into the existing run-time environment of a Cyber-Physical System (CPS). The design of a software component involves designers from various viewpoints such as control theory, software engineering, safety, etc. In practice, while a designer from one discipline focuses on the core aspects of his field (for instance, a control engineer concentrates on designing a stable controller), he neglects or considers less importantly the other engineering aspects (for instance, real-time software engineering or energy efficiency). This may cause some of the functional and non-functional requirements not to be met satisfactorily. In this work, we present a co-design framework based on timing tolerance contract to address such design gaps between control and real-time software engineering. The framework consists of three steps: controller design, verified by jitter margin analysis along with co-simulation, software design verified by a novel schedulability analysis, and the run-time verification by monitoring the execution of the models on target. This framework builds on CPAL (Cyber-Physical Action Language), an MDE design environment based on model-interpretation, which enforces a timing-realistic behavior in simulation through timing and scheduling annotations. The application of our framework is exemplified in the design of an automotive cruise control system. [less ▲]

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See detailInsights on the Performance and Configuration of AVB and TSN in Automotive Ethernet Networks
Migge, Jörn; Villanueva, Josetxo; Navet, Nicolas UL et al

in Proc. Embedded Real-Time Software and Systems (ERTS 2018) (2018, February 02)

Switched Ethernet is profoundly reshaping in-car communications. To meet the diverse real-time requirements in automotive communications, Quality-of-Service protocols that go beyond the mere use of ... [more ▼]

Switched Ethernet is profoundly reshaping in-car communications. To meet the diverse real-time requirements in automotive communications, Quality-of-Service protocols that go beyond the mere use of priorities are required. In this work, the basic questions that we investigate on a case-study with diverse and demanding communication requirements is what can we expect from the various protocols aimed at providing a better timing Quality of Service on top of Ethernet? And how to use them? Especially how to use them in a combined manner. We will focus on the Credit-Based Shaper of AVB, the Time-Aware Shaper of TSN and the use of priorities as defined in IEEE802.1Q. The performance metrics considered are the distributions of the communication latencies, obtained by simulation, as well as upper bounds on these quantities obtained by worst-case schedulability analysis. If there have been over the last 5 years numerous studies on the performance of AVB CBS, the literature on comparing AVB to TSN and other candidate protocols is still sparse. To the best of our knowledge, this empirical study is the first to consider most protocols currently considered in the automotive domain, with the aim to gain insights into the different technological, design and configurations alternatives. In particular, an objective of this study is to identify key problems that need to be solved in order to further automate network design and configuration. [less ▲]

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See detailSimulation-Based Fault Injection as a Verification Oracle for the Engineering of Time-Triggered Ethernet networks
Fejoz, Loïc; Regnier, Bruno; Miramont, Philippe et al

in Proc. Embedded Real-Time Software and Systems (ERTS 2018) (2018, February 02)

TTEthernet (TTE) is considered for use as high-speed backbone in the avionics of next-generation orbital space launchers. Given the key role of communication in launchers, the OEM must acquire a precise ... [more ▼]

TTEthernet (TTE) is considered for use as high-speed backbone in the avionics of next-generation orbital space launchers. Given the key role of communication in launchers, the OEM must acquire a precise understanding of TTE’s functioning and its performances in nominal and error conditions. This holds especially true for the clock synchronization algorithm, the cornerstone of time-triggered communication in TTE, which involves complex distributed algorithms. In this study, we use both an experimental platform and fault-injection on a simulation model to gain quantified insights in these questions. We first describe a fine-grained simulation model of TTE model and discuss how it has been validated against communication traces recorded on the TTE platform. We then present experiments that evaluate the accuracy of the clock synchronization in TTE in the fault-free case as well as considering permanent link failure and transient transmission errors. Finally, we discuss what we have learned during the project in terms of development process and programming language support for complex simulation models used in the design of critical systems. [less ▲]

Detailed reference viewed: 132 (11 UL)