What is RTE (Realtime Environment) in AUTOSAR?

The RTE is the runtime representation of the Virtual Function Bus for a specific ECU. The RTE provides a communication abstraction to AUTOSAR Software Components providing the same interface and services for inter ECU (using CAN, LIN, Flexray, MOST, etc.) or intra-ECU communication.
 
The AUTOSAR Runtime Environment has the responsibility to provide a uniform environment to AUTOSAR Software Components to make the implementation of the software components independent from communication mechanisms and channels.