OCS drivers are the components which connect Sentinel to an actual OCS.
OCS drivers fulfil two essential purposes:
providing implementations of session charging and immediate event charging functionality, triggered through the exposed OCS driver interface, by the Sentinel-internal mediation layer
translating between Diameter Ro, which is used internally in the mediation layer, and the actual protocol of the OCS in use.
OCS drivers are realized as child SBBs which are referenced by the main Sentinel front-end SBBs (SS7, Diameter, and SIP services). Each OCS driver moreover has a name which must be unique across the whole Sentinel system. During the course of a session, Sentinel examines the
OcsEntityId session state field, and selects the OCS driver whose name matches one to be used for an OCS interaction.
Do not change the
OcsEntityId during the course of a session, following an OCS interaction (with a different OCS).
Each OCS Driver module has an associated Mappers module, which holds the Sentinel mappers required to do the conversion between the Sentinel-internal Diameter Ro format and the format required by the actual OCS.
OCSes with alternative protocols — connecting to OCSes which use a protocol different to Diameter Ro (such as Diameter CCA)
MSCC-Multiplexing — changing the implementation of the Session-Charging and Immediate-Event-Charging FSMs to provide an implementation which opens a dedicated session to the OCS for each Multiple-Services-Credit-Control (MSCC) AVP found in the original CCR from the mediation layer.