Gy/Ro session initiation request (i.e. CCR-I) messages received from online charging clients to initiate credit-control sessions are load balanced across a collection of OCS servers connected to the PCA DSR that can serve the Diameter Request. Subsequent Gy/Ro CCR-U/T messages within the session are routed to the same OCS that served the CCR-I either by means of destination-host routing or by the stateful mechanism.
OCS Pool Selection modes are configurable via the NOAM GUI Main Menu: Policy and Charging > Configuration > Online Charging DRA > Network-Wide Options > OCS Pool Selection Mode.
One-time Gy/Ro credit-control events received from online charging clients are handled in the same manner as session initiation request (CCR-I) messages and are load balanced across a collection of OCS servers connected to the DSR that can serve the Diameter request.