References of "Migge, Jörn"
     in
Bookmark and Share    
Full Text
See detailA Hybrid Machine Learning and Schedulability Method for the Verification of TSN Networks
Mai, Tieu Long UL; Navet, Nicolas UL; Migge, Jörn

Report (2019)

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 ▲]

Detailed reference viewed: 101 (13 UL)
Full Text
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 ▲]

Detailed reference viewed: 175 (32 UL)
Full Text
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 ▲]

Detailed reference viewed: 61 (1 UL)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 35 (2 UL)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 288 (16 UL)
Full Text
Peer Reviewed
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 SAE International Journal of Passenger Cars—Electronic and Electrical Systems (2018), 11(3),

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 (Advanced Driver-Assistance 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 meeting the timing constraints for the rest of the traffic. We then discuss the limitations of the pre-shaping mechanism and what is needed to facilitate its adoption. [less ▲]

Detailed reference viewed: 32 (1 UL)
Full Text
Peer Reviewed
See detailInsights on the performance and configuration of AVB and TSN in automotive applications
Navet, Nicolas UL; Villanueva, Josetxo; Migge, Jörn et al

Scientific Conference (2017, November 01)

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 ▲]

Detailed reference viewed: 85 (5 UL)
Full Text
Peer Reviewed
See detailTiming verification of real­time automotive Ethernet networks: what can we expect from simulation?
Navet, Nicolas UL; Seyler, Jan; Migge, Jörn

Scientific Conference (2016, January 28)

Switched Ethernet is a technology that is profoundly reshaping automotive communication architectures as it did in other application domains such as avionics with the use of AFDX backbones. Early stage ... [more ▼]

Switched Ethernet is a technology that is profoundly reshaping automotive communication architectures as it did in other application domains such as avionics with the use of AFDX backbones. Early stage timing verification of critical embedded networks typically relies on simulation and worst-case schedulability analysis. When the modeling power of schedulability analysis is not sufficient, there are typically two options: either make pessimistic assumptions or ignore what cannot be modeled. Both options are unsatisfactory because they are either inefficient in terms of resource usage or potentially unsafe. To overcome those issues, we believe it is a good practice to use simulation models, which can be more realistic, along with schedulability analysis. The two basic questions that we aim to study here is what can we expect from simulation, and how to use it properly? This empirical study explores these questions on realistic case-studies and provides methodological guidelines for the use of simulation in the design of switched Ethernet networks. A broader objective of the study is to compare the outcomes of schedulability analyses and simulation, and conclude about the scope of usability of simulation in the design of critical Ethernet networks. [less ▲]

Detailed reference viewed: 192 (5 UL)
Full Text
Peer Reviewed
See detailPerformance impact of the interactions between time -triggered and rate-constrained transmissions in TTEthernet
Boyer, Marc; Daigmorte, Hugo; Navet, Nicolas UL et al

Scientific Conference (2016, January 27)

Switched Ethernet is becoming a de-facto standard in industrial and embedded networks. Many of today’s applications benefit from Ethernet’s high bandwidth, large frame size, multicast and routing ... [more ▼]

Switched Ethernet is becoming a de-facto standard in industrial and embedded networks. Many of today’s applications benefit from Ethernet’s high bandwidth, large frame size, multicast and routing capabilities through IP, and the availability of the standard TCP/IP protocols. There are however many variants of Switched Ethernet networks, just considering the MAC level mechanisms on the stations and communication switches. An important technology in that landscape is TTEthernet, standardized as SAE6802, which allows the transmission of both purely time-triggered (TT) traffic and sporadic (or rate-constrained - RC) traffic. To the best of our knowledge, the interactions between both classes of traffic have not been studied so far in realistic configurations. This work aims to shed some light on the kind of performances, in terms of latencies, jitters and useful bandwidth that can be expected from a mixed TT and RC configuration. The following issues will be answered in a quantified manner by sensitivity analysis: How do both classes of traffic interfere with each other? What are the typical worst-case latencies and useful bandwidth that can be expected for a RC stream for various TT traffic loads? What is the overall impact of TTEthernet integration policy for the RC traffic? This study builds on a worst-case traversal time analysis developed by the authors for SAE6802, and explores these questions by experiments performed configurations of various sizes. [less ▲]

Detailed reference viewed: 186 (7 UL)
Full Text
Peer Reviewed
See detailTiming verification of real-time automotive Ethernet networks: what can we expect from simulation?
Navet, Nicolas UL; Seyler, Jan; Migge, Jörn

Scientific Conference (2015, May 23)

Switched Ethernet is a technology that may profoundly reshape automotive communication architectures as it did in other application domains such as avionics with the use of AFDX backbones. Ethernet is ... [more ▼]

Switched Ethernet is a technology that may profoundly reshape automotive communication architectures as it did in other application domains such as avionics with the use of AFDX backbones. Ethernet is meant in vehicles not only for the support of infotainment applications but also to transmit time-sensitive data used for the real-time control of the vehicle and ADAS functions. In such use-cases, the temporal behavior of the communication architecture must be carefully validated. Early stage timing verification of critical embedded networks typically relies on simulation and worst-case schedulability analysis, which basically consists in building a mathematical model of the worst possible situations that can be encountered at run-time. The two basic questions that we aim to study here is what can we expect from simulation? And how to use it properly? This empirical study explores these questions and provides methodological guidelines for the use of simulation in the design of switched Ethernet networks. A broader objective of the study is to compare the outcomes of schedulability analyses and simulation, and conclude about the scope of usability of simulation in the design of critical Ethernet networks. [less ▲]

Detailed reference viewed: 104 (4 UL)
Peer Reviewed
See detailTiming verification of automotive communication architectures using quantile estimation
Navet, Nicolas UL; Louvart, Shehnaz; Villanueva, Jose et al

Scientific Conference (2014, March 07)

Early stage timing verification on CAN traditionally relies on simulation and schedulability analysis, also known as worst-case response time (WCRT) analysis. Despite recent progresses, the latter ... [more ▼]

Early stage timing verification on CAN traditionally relies on simulation and schedulability analysis, also known as worst-case response time (WCRT) analysis. Despite recent progresses, the latter technique remains pessimistic espe cially in complex networking architectures with gateways and heterogeneous communication stacks. Indeed, there are practical cases where no exact WCRT analysis is available, and merely upper bounds on the response times can be derived, on the basis of which unnecessary conservative design choices may be made. Simulation, on the other hand, does not provide any guarantees per se and, in the context of critical networks, should only be used along with an adequate methodology. In this paper, we argue for the use of quantiles of the response time distribution as performance metrics providing an adjustable trade-off between safety and resource usage optimization. We discuss how the exact value of the quantile to consider should be chosen with regard to the criticality of the frames, and illustrate the approach on two typical automotive use -cases. [less ▲]

Detailed reference viewed: 86 (4 UL)
Peer Reviewed
See detailIntegrating end-system frame scheduling for more accurate AFDX timing analysis
Boyer, Marc; Santinelli, Luca; Navet, Nicolas UL et al

Scientific Conference (2014, February 07)

Avionics systems distributed on AFDX networks are subject to stringent real-time constraints that require guaranteeing the Worst-Case Traversal Time (WCTT) on the network for each of the data flows. Over ... [more ▼]

Avionics systems distributed on AFDX networks are subject to stringent real-time constraints that require guaranteeing the Worst-Case Traversal Time (WCTT) on the network for each of the data flows. Over the last 10 years, since the initial use of Network Calculus in certification, important progresses have been made in AFDX timing verification. The maximum pessimism for the latencies is now known to range from 10 to 25% on realistic systems. Further progresses towards more accurate timing analysis can still be made by considering additional temporal information. In this paper, we show that integrating the knowledge of the scheduling of the frames that is done within an end-system in the timing analysis enables to dramatically reduce the WCTT bounds computed by Network Calculus. Indeed, in our experiments performed on a realistic configuration provided by Thales Avionics, this technique reduces the WCTT upper bound by 40% on average over all flows. The reason is that the scheduling of the frames shapes the outgoing traffic, reducing thus peaks of load on the outgoing traffic , which can be accounted for in the timing analysis. Importantly, because the scheduling of the frames within the end-systems is in the scope of the network supplier, unlike the scheduling of tasks done at the application level, the approach presented here does not imply major changes in the design process. [less ▲]

Detailed reference viewed: 69 (6 UL)
Full Text
Peer Reviewed
See detailCombining static priority and weighted round-robin like packet scheduling in AFDX for incremental certification and mixed-criticality support
Boyer, Marc; Navet, Nicolas UL; Fumey, Marc et al

in Proceedings of the 5th European Conference for Aeronautics and Space Sciences (EUCASS) (2013, July 01)

The Deficit Round Robin (DRR) policy can be used at the outgoing ports of communication switches to schedule distinct classes of frames, providing each class with a guaranteed share of the network ... [more ▼]

The Deficit Round Robin (DRR) policy can be used at the outgoing ports of communication switches to schedule distinct classes of frames, providing each class with a guaranteed share of the network bandwidth. The independence between traffic classes helps to improve the incremental design process, incremental certification and scheduling flows with mixed criticalities. DRR leads however to a less efficient use of hardware resources, this is why we also envisage the combined use of DRR and Static Priority (SP). We then provide a first quantitative assessment on a realistic case-study about the use of DRR, possibly combined with SP, in avionics networking and shed some light on its range of applicability. [less ▲]

Detailed reference viewed: 47 (3 UL)