1. Configuration Guide
  2. External Policy Servers
  3. Network Provided Location Information
  4. NPLI Implementation

NPLI Implementation

The Oracle Communications Session Border Controller (SBC) provides for an explicit subscription to NPLI changes resulting in the dynamic update of NPLI.

This NPLI implementation triggered by an originating mobile device typically involves a message exchange similar to the following.

  1. Upon receiving the initial INVITE from the mobile handset, the P-CSCF sends an AAR command to the PCRF via the Rx Interface. This AAR contains a Required-Access-Info AVP that requests user location reports as they become available to the PCRF.
  2. The P-CSCF buffers the INVITE pending the receipt of an AAA command from the PCRF. The AAA contains a 3GPP-User-Location-Info AVP along with a RAT-Type AVP. Depending upon network design, the AAA may also contain a proprietary MSISDN AVP, although this is not usually the case.

    Note:

    If you have set the location-optimization-on-aar option on the applicable ext-policy-server element, the SBC still receives the AAA, but it then waits for a RAR, from which it gets the 3GPP-user-location.
  3. Upon receiving the AAA, the P-CSCF, using values contained in the 3GPP-User-Location-Info attribute, and the RAT-Type attribute, adds an extended PANI header to the buffered INVITE. If an MSISDN is included within the AAA, the P-CSCF also adds a P-Subscription-MSISDN header to the buffered INVITE.

    Note:

    If you have set the location-optimization-on-aar option on the applicable ext-policy-server element, the SBC still receives the AAA, but it then waits for a RAR, from which it gets the 3GPP-user-location.
  4. The P-CSCF caches received attribute values, and forwards the altered INVITE to the IMS core.
  5. At any point during the call (from initial session establishment to session termination) the PCRF can send a Re-Auth Request (RAR) that contains updated NPLI conveyed by the 3GPP-User-Location-Info, RAT-Type, IP-CAN-Type, or MSISDN AVPs.
  6. After receiving the RAR, the P-CSCF updates the cached attribute values.
  7. All subsequent re-INVITES and UPDATES contain the PANI and P-Subscription-MSISDN headers populated with the most recent cache values.

You configure global NPLI parameters in the sip-config or in profiles of those same NPLI parameters as an npli-profile element and apply them to a sip-interface to establish more granular control of NPLI management. The configuration at the sip-interface takes precedence. These configurations are explained in sections below.

Configuration Conflict

The npli-upon-register component of an npli-profile conflicts with the provision-signaling-flow configuration when they overlap. Exercise caution when applying a npli-profile to ensure it does not conflict with any provision-signaling-flow configuration that you need. The SBC provides a configuration verification error when it detects this conflict.