Aperiodic traffic in response time analyses with adjustable safety level

Khan, Dawood Ashraf; Navet, Nicolas; Bavoux, Bernard; Migge, Jörn

doi:10.1109/etfa.2009.5347149

Cited by 13 publications

(10 citation statements)

References 10 publications

(15 reference statements)

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“…The integration of this scheduling in the modeling of flows should distribute temporally the transmission of packets and very likely reduce the waiting time of packets in output buffers. Moreover, the sporadic characteristic of avionics flows could be taken into account with the help of a probabilistic modeling, as it has been proposed for the a periodic traffic in the automotive context [Khan et al (2009)]. This leads to a probabilistic analysis of the worst case delay of flows.…”

Section: Resultsmentioning

confidence: 99%

Methods and Tools for the Temporal Analysis of Avionic Networks

Scharbarg¹,

Fraboul²

2010

New Trends in Technologies: Control, Management, Computational Intelligence and Network Systems

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IntroductionThanks to the Integrated Modular Avionics concept [ARI (1991;1997)], functions developed for civilian aircraft share computation resources. However, the continual growing number of these functions implies a huge increase in the quantity of data exchanged and thus in the number of connections between functions. Consequently, traditional ARINC 429 buses [ARI (2001)] can't cope with the communication needs of modern aircraft. Indeed, ARINC 429 is a single-emitter bus with limited bandwidth and a huge number of buses would be required. Clearly, this is unacceptable in terms of weight and complexity. In order to cope with this problem, the AFDX (Avionics Full DupleX Switched Ethernet) [ARI (2002[ARI ( -2005] was defined and has become the reference communication technology in the context of avionics. AFDX is a full duplex switched Ethernet network to which new mechanisms have been added in order to guarantee the determinism of avionic communications. This determinism has to be proved for certification reasons and an important challenge is to demonstrate that an upper bound can be determined for end-toend communication delays. An important assumption is that all the avionics communication needs can be statically described: asynchronous multicast communication flows are identified and quantified. All these flows can be statically mapped on the network of AFDX switches. For a given flow, the end-to-end communication delay of a frame can be described as the sum of transmission delays on links and latencies in switches. Thanks to full duplex links characteristics, no collision can occur on links and transmission delays on links depend solely on bandwidth and frame length. But, as confluent asynchronous flows compete, on each switch output port, highly variable latencies can occur when a frame crosses a switch. Thus it is necessary to analyze these latencies in order to determine the upper bounds on end-to-end communication delays for each flow. At least three approaches have been proposed in order to compute a worst-case bound for each communication flow of the avionic applications on an AFDX network configuration. They are based on network calculus, trajectories and model checking. Such a worst-case communication delay analysis allows the comparison between the computed upper bounds and the constraints on the communication delays of each flow. Moreover it allows the scaling of the switches memory buffers in order to avoid buffer overflow and frame losses. However, communication delays measured on a real configuration are much lower than the computed upper bound. This is mainly due to the fact that rare events are difficult to observe on a real configuration in a reasonable time.

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Section: Resultsmentioning

confidence: 99%

Methods and Tools for the Temporal Analysis of Avionic Networks

Scharbarg¹,

Fraboul²

2010

New Trends in Technologies: Control, Management, Computational Intelligence and Network Systems

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“…Bounds on the worst case response times have been provided [2] and [3], researchers then started to integrate the limitations of hardware [4] and the communication stack, as the first analyses usually overlooked them, and also considered the effect of aperiodic traffic on CAN frame response times [5] and the consequences of transient perturbations [6]. Of course, methods to minimize the response times, or make them more predictable, were investigated too, e.g.…”

Section: Previous Workmentioning

confidence: 99%

Impact of clock drifts on CAN frame response time distributions

2011

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Abstract:The response time distributions of the frames sent on a Controller Area Network (CAN) bus are of prime interest to dimension and validate automotive electronic architectures. However, the existing work on the timing behaviour of the CAN network does not take into account that all the data exchanges between the Electronic Control Units (ECUs) are driven by different and independent clocks which are subject to clock drifts. This paper proposes a model for clock drifts and describes their impact on the CAN frame response time distributions. By implementing the clock drifts in a CAN simulation tool, we show experimentally that the response time distributions converge, for drift values chosen randomly within the same range on all ECUs, whatever the initial phasings between the sending nodes. Furthermore, we show that, as a result of the clock drifts, the situations leading to the worst case response times are transient.

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“…In practice, finding the arrival function may be easy as usually the work-arrivals follow the Poisson distribution function for which there is a closed form expression. However, we can also model some other CDFs with the numerical-approximation for count models of the CDF or based on simulations, see [18]; again this is not the goal of the current work. Component Interfaces To model interfaces of WSN components we make use of an approach similar to the real-time calculus [17] and to the assume/guarantee interfaces [19] tailored towards guarantees on the bandwidth-availability, and requests.…”

Section: Node Component Modelmentioning

confidence: 99%

Probabilistic Bandwidth Assignment in Wireless Sensor Networks

Khan

Nefzi

Santinelli

et al. 2012

Wireless Algorithms, Systems, and Applications

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Abstract. With this paper we offer an insight in designing and analyzing wireless sensor networks in a versatile manner. Our framework applies probabilistic and component-based design principles for the wireless sensor network modeling and consequently analysis; while maintaining flexibility and accuracy. In particular, we address the problem of allocating and reconfiguring the available bandwidth. The framework has been successfully implemented in IEEE 802.15.4 using an Admission Control Manager (ACM); which is a module of the MAC layer that guarantees that the nodes respect their probabilistic bandwidth assignment as well as the bandwidth assignment policy applied. The proposed framework also aims to accurately analyze the behaviors of communication protocols for energy-consumption and reliability purposes. We evaluate the probabilistic bandwidth assignment methods using CSMA/CA access protocol of IEEE 802.15.4. Furthermore, we analyze the behavior of the ACM and compare the performance of the network with and without using the ACM against the original standard. The simulation results show that the use of ACM increases the overall performance of the network. 4

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Aperiodic traffic in response time analyses with adjustable safety level

Cited by 13 publications

References 10 publications

Methods and Tools for the Temporal Analysis of Avionic Networks

Methods and Tools for the Temporal Analysis of Avionic Networks

Impact of clock drifts on CAN frame response time distributions

Probabilistic Bandwidth Assignment in Wireless Sensor Networks

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