Description of the illustration sbsig_sip_ocs

The call flow shows a SIP to SIP session initiated by SIP User 1 to SIP User 2. Service Controller, working with Online Mediation Controller, makes the initial Diameter Capabilities-Exchange Request (CER) to the OCS triggered by the SIP User 1 INVITE. The OCS responds with a Capabilities-Exchange Answer (CEA). Service Controller then sends a Diameter Credit-Control-Request (CCR) used by the OCS to initiate rating on the session. A valid Credit-Control-Answer (CCA) from the OCS results in a SIP INVITE sent to SIP User 2. The SIP session connects with additional CCR/CCA requests made to the OCS after invitation acknowledgement from both SIP Users. When SIP User 1 terminates the session, Service Broker sends a final CCR to the OCS for final accounting.