NAP Notifications
When you modify subscriber details, the NAP server, LDAP server, and PCF or PCRF perform the following operations:
NAP request termination on the PCRF
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The LDAP server updates the NAP server with the modified details.
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The NAP server broadcasts the Subscriber Change Notification message to the connected PCRF server. The message contains the unique identifier, and MSISDN or IMSI ID.
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After receiving the message, the PCRF sends an acknowledgment to NAP. The PCRF then searches for the local session.
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If the subscriber session is active on the PCRF, then PCRF requests the updated subscriber information from SPR or LDAP server. Depending upon the information it receives, PCRF updates the local session with the updated subscriber information and sends a Re-Auth-Request (RAR) for the Policy and Charging Rules Function (PCEF). For example, if PCRF identifies a session for the notification that contains the specified MSISDN in the PCRF then it triggers a Gx-RAR for the subscriber sessions.
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If PCRF does not find the subscriber session locally, then the Policy Server forwards the Subscriber Change Notification to PCF. After receiving notification, PCF seeks the session locally and takes the appropriate action.
NAP request termination on PCF
When profile changes occur in NAP, it signifies that certain policies are added or modified. In this situation, the PCF performs the following:
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Upon receiving a notification from NAP, the PCF initiates a requery or refresh request.
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The PCF sends an N28 Subscribe Update request seeking the details of the policies that are added or updated.
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After receiving the updates, the PCF reevaluates the policies to determine the updated policies and sends the Update_Notify message to SMF (over the N7 interface).