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Among the several enhancements in AUTOSAR Release 4.0 is the addition of an End-to-End (E2E) Communication Protection Library. This library defines several E2E profiles, each of which implements a combination of End-to-End protection mechanisms such as sequence counters, data IDs and CRCs. Two of these profiles, Profiles 1 and 2, are intended to protect inter-ECU communication via databus systems like FlexRay or CAN, and are designed to address various communication faults. Although the AUTOSAR specification includes detailed descriptions of the profiles, it provides only limited insight about the fault coverage that can be obtained when using these profiles to detect communication faults. This paper focuses on the fault detection capabilities that profiles 1 and 2 offer with respect to message corruptions.

FlexRay is a time triggered automotive communication protocol that connects ECUs (Electronic Control Units) on which distributed automotive applications are executed. If exact agreement (e.g. on physical values measured by redundant sensors on different ECUs) must be reached in the presence of asymmetric communication faults, a byzantine agreement protocol like Signed Messages (SM) can be utilized. This paper gives examples of how byzantine faults can emerge in a FlexRay-based system and proposes optimizations for a FlexRay-specific implementation of the SM protocol. The protocol modifications allow for a reduction in the number of protocol messages under a slightly relaxed fault model, as well as for a reduction in the number of messages to be temporarily stored by the ECUs.

FlexRay is a communications protocol intended, among other things, to support safety-relevant applications. The FlexRay protocol has several characteristics that make it well suited for such applications, but it also has some fundamental differences from other protocols that will likely influence the way FlexRay is used in a system. This paper presents a brief overview of FlexRay, identifying some of the benefits of the protocol, but also pointing out some things system designers should keep in mind when using FlexRay. Where appropriate, FlexRay will be compared with other communications protocols such as CAN to point out differences that will affect the way FlexRay systems are designed.