Worst-Case Timing Analysis of AeroRing- A Full Duplex Ethernet Ring for Safety-critical Avionics

Avionics implementation with less cables will clearly improve the efficiency of aircraft while reducing weight and maintenance costs. To fulfill these emerging needs, an innovative avionics communication architecture, based on Gigabit Full Duplex Ethernet ring, is proposed in this paper. To adapt this COTS technology to safety-critical avionics, an adequate tuning process of the communication protocol and the choice of reliability mechanisms to achieve timely and reliable communications are first detailed. Then, efficient timing analyses of such a proposal based on Network Calculus are conducted, accounting the impact of a ring topology and the specified reliability mechanisms. Third, these general analyses are illustrated in the case of a realistic avionic application, to replace the AFDX backup network with AeroRing, to reduce wires, while guaranteeing timely communications

Specification and Performance Indicators of AeroRing—A Multiple-Ring Ethernet Network for Avionics Embedded Systems

The complexity and costs of the avionics communication architecture are increasing exponentially with the increasing number of embedded computers over the last few decades. To limit the cabling complexity and the deployment costs of such a communication architecture, we specify a new Gigabit multiple-ring Ethernet network, called AeroRing, while meeting the avionics requirements. First, we describe the current Aircraft Data Communication Network (ADCN) to highlight the main characteristics and requirements that have to be fulfilled by our solution. Then, we give an overview of the most relevant solutions to improve ADCN performance and relate them to AeroRing. Afterwards, we detail the specifications and the main Performance Indicators (PIs) of AeroRing. Finally, sensitivity and validation analyses of AeroRing are conducted through a realistic avionics application, regarding the various PIs, in comparison to the backbone network of the ADCN, the Avionics Full DupleX Switched Ethernet (AFDX). The computed AeroRing performance metrics show its ability to guarantee the avionics requirements

Real-Time Ethernet Solutions supporting Ring topology from an Avionics Perspective: a Short Survey

To cope with the increasing quantity of wires, thus the weight and integration costs in avionics, an implementation of a new avionics communication architecture with less cables will clearly improve the efficiency of aircraft, while reducing the deployment costs. Furthermore, such a communication ar- chitecture shall be efficient to meet the design requirements, in terms of predictability and availability, for the least amount of money. Therefore, the AFDX compatibility, a minimized (re)- configuration effort and costs are among the most important issues to guarantee. On the other hand, the recent research effort towards defining new communication solutions, to guarantee a high availability level with limited cabling complexity for real- time applications, has renewed the interest in ring topology. Therefore, the main objective of this paper is benchmarking the most relevant solutions, based on Ethernet technology and supporting ring topology, vs avionics requirements, and we particularly focus on the main Performance Indicators, specified in IEC 61784-2, of each one of them

Enhanced Worst-case Timing Analysis of Ring-based Networks with Cyclic Dependencies using Network Calculus

The recent research effort towards defining new communication solutions for cyber-physical systems (CPS), to guarantee high availability level with limited cabling costs and complexity, has renewed the interest in ring-based networks. This topology has been recently used for various networked cyber-physical systems (Net-CPS), e.g., avionics and automotive, with the implementation of many Real Time Ethernet (RTE) profiles. A relevant issue for such networks is to prove timing predictability, a key requirement for safety-critical systems. For the most common ring-based Real Time Ethernet (RTE) profiles, conducting such performance analyses has been greatly simplified due to their implemented time-triggered communication scheme, e.g. Master/slave or TDMA. Unlike these existing approaches, we are interested in this paper in event-triggered ring-based networks, which guarantee high resource utilization efficiency and (re)confi\-gura\-tion flexibility, at the cost of increasing the timing analysis complexity. The implementation of such a communication scheme on top of a ring topology actually induces cyclic dependencies, in comparison to time-triggered solutions. To cope with this arising issue of cyclic dependencies, only few techniques have been proposed in the literature, mainly based on Network Calculus framework, and consist in analyzing locally the delay upper bound in each crossed node, resulting in pessimistic end-to-end delay bounds. Hence, the main contribution in this paper is enhancing the delay bounds tightness of such networks, through an innovative global analysis based on Network Calculus, considering the flow serialization phenomena along the flow path. An extensive analysis of such a proposal is conducted herein regarding the accuracy of delay bounds and its impact on the system performance, i.e., scalability and resource-efficiency; and the results highlight its outperformance, in comparison to conventional methods