Autosar standardizes the ECU software architecture, which promotes exchange and reuse of ECU software components between vehicle manufacturers and suppliers as well as their use within different vehicle platforms and variants.

From an abstract point of view (i.e. at system design time), the Run Time Environment (RTE) is the run-time implementation of the Virtual Functional Bus (VFB) on a specific ECU.

The VFB translates the relevant communication mechanisms to the application layer software.

AUTOSAR defines a standardized component model allowing the decomposition of the application software layer into well structured coupled components.

The RTE abstracts the application layer from implementation abd hardware specificities. Thus, the RTE is a novel middleware layer technology which allows transfer of the application layer software components across the network.

These components can be moved across ECUs during concept phase or reused across projects (ideally without touching the source code.