Graphic depicts IVR workflow as follows:
At the top, a box representing Online Mediation Controller, which contains (from top to bottom) Balance Manager Service, Balance Manager Web Service and WS SSU all connected by two-way arrows. To the right and outside of the Online Mediation Controller box from the Balance Manager Service, two way arrows connect to a OCS such as BRM or ECE, and its subscriber and voucher databases.
Two way arrows point down and out of the Online Mediation Controller box from the WS SSU to the IVR Web Server, then Media Server, then Media Gateway to the Subscriber at the bottom.