The diagram below provides an overview of the Rasa Open Source architecture. The two primary components are Natural Language Understanding (NLU) and dialogue management.
NLU is the part that handles intent classification, entity extraction, and response retrieval. It's shown below as the NLU Pipeline because it processes user utterances using an NLU model that is generated by the trained pipeline.
The dialogue management component decides the next action in a conversation based on the context. This is displayed as the Dialogue Policies in the diagram.