The report server architecture is base in Message queues. When someone wants to produce a report, a message is appended to a queue. This message, to be consumed asynchronous, have all the information needed to the consumer process precede with data retrieval and report generation. From the report name and query filters ending in the Manager method to process the data retrieval, all must be present in the queued message.
The Report Server can be on the same machine and instance of the application server, or in a different machine, all depending on the system configuration.