You can configure the OCCSM to retrieve P-Charging Function Addresses (PCFA) information from a Home Subscriber Server (HSS). The OCCSM can get this address from the HSS over the Cx interface during subscriber registration. The OCCSM, subsequently, can use PCFA addresses to populate the outgoing P-Charging-Function-Address headers it sends to an application server in INVITEs and registration success messages it sends to a P-CSCF. As a result, your infrastructure can use PCFA information provisioned at the HSS as the charging addresses for your subscribers. OCCSM use of the charging information AVP is compliant with ETSI TS 129 229. The OCCSM generates the applicable P-Charging-Function-Address headers per RFC 7315.

When you enable this feature, the OCCSM, acting as S-CSCF, can decode the Charging-Information AVP, save the information locally, and insert P-Charging Function Address headers into specific message, assuming they are not already present. Applicable scenarios include registrations, registration refreshes, and dialog creating initial INVITE messages. In addition, if an applicable INVITE arrives with the PCFA header already populated, the OCCSM transparently forwards the INVITE with that PCFA information.

This feature does not apply to out of dialog messages, standalone requests or messages subsequent to an initial INVITE.

Applicable PCFA information includes IP addressing for the objects that perform the following functions:

• Charging Collection Function (CCF), which resides on the Charging Data Function (CDF) device
• Event Charging Function (ECF), which resides on the Online Charging Function (OCF) device

Depending on the scenario, the HSS provides the primary or both primary and secondary device addressing. The HSS presents the CCF for off-line charging functions, and the ECF for on-line charging functions.

You enable this functionality on the OCCSM using the add-pcfa parameter within the sip-config as shown below. The default is disabled.

ORACLE(sip-config)#add-pcfa enabled

When enabled, the OCCSM adds the following behaviors:

• Upon receiving a REGISTER request, and when the information is not already available locally, fetches PCFA information from the HSS using SAR/SAA exchange and stores PCFA information for each contact locally.
• Adds PCFA information, both primary and secondary, to the 200 OK when responding to a REGISTER message.
• If the CCF and/or ECF values are available for the originating user, the OCCSM inserts these additional CCF and/or ECF values in the PCFA header of an outgoing INVITE (Orig) towards the TAS.

  Note:

  The first instance of CCF and/or ECF header field parameters are the primary address(es).
• When forwarding an INVITE towards a registered terminating party, the OCCSM uses the value of the locally stored CCF and/or ECF to populate the PCFA headers in outgoing INVITE (Term) messages towards the TAS.
• If the CCF and/or ECF values are available for the terminating user, the OCCSM inserts these additional CCF and/or ECF values in the PCFA header of an outgoing INVITE (Term) towards the TAS.
• For un-registered terminating users for whom the OCCSM has does not have PCFA details available locally, the OCCSM performs a SAR-SAA exchange with the HSS to get this information. The OCCSM then:
  • Stores the values locally
  • Uses the values to populate the PCFA in outgoing INVITE (Term) messages towards the TAS.
  • Uses the values to populate the PCFA in outgoing INVITE messages towards core systems, including Border Gateway Control functions (BGCFs).
• For un-registered originating users for whom the OCCSM has does not have PCFA details available locally, the OCCSM performs a SAR-SAA exchange with the HSS to get this information. The OCCSM then:
  • Stores the values locally
  • Uses the values to populate the PCFA in outgoing INVITE (Orig) messages towards the TAS.
• If it receives an INVITE from a P-CSCF that has PCFA information, the OCCSM retains that information and populates it within the outgoing INVITE (Orig) towards the TAS.

This feature supports real time configuration and HA deployments.