Injection of aggregated error flags as a means to guarantee consistent error detection in CAN

Although the specification of CAN states that this protocol provides data consistency, it is well know that said property does not hold for certain specific error scenarios affecting the last bits of a CAN frame, and a number of solutions have been already suggested. Moreover, for a long time it has been thought that the errors affecting the initial or intermediate bits of a CAN frame cannot cause any inconsistency. In this paper we show that this assumption is false, and that such kinds of message inconsistencies are also possible for certain combinations of multiple channel errors. After describing these unreported scenarios of inconsistency, we present a mechanism that guarantees the consistent detection of said scenarios and eliminates the possibility of suffering this kind of inconsistencies. This mechanism is therefore useful for the design of highly-dependable applications over CAN.