Integration with 'downstream' systems architecture
General requirement
One of the core functions of the OIR is the ability to interface with so called 'downstream' authoritative identity systems such as directory servers, etc. for the purpose of handing out the canonical identity data which OIR has collected and normalized from various 'Systems Of Record' [SORs]. In order for the OIR system to be able to seamlessly provide data to downstream systems and make the OIR system flexible and extensible, the integration subsystem needs to be designed in such a way that does not tightly couple OIR to any downstream systems.
Two complementary approaches can be taken to do this: an enterprise service bus and a plugin based provisioning API .