From the perspective of the Endeca Presentation API, the Agraph program behaves identically to a Dgraph program.
When an Aggregated MDEX Engine receives a request, it sends the request to all of the distributed MDEX Engines. Each MDEX Engine processes the request and returns its results to the Aggregated MDEX Engine which aggregates the results into a single response and returns that response to the client, via the Endeca Presentation API.
In the following illustration, one Agraph coordinates three Dgraphs.
