A.9 Handling of MPS Session

29.2143GPPPolicy and charging control over Rx reference pointRelease 17TS

When the P-CSCF receives an authorised Resource-Priority header field or a temporarily authorised Resource-Priority header field containing an appropriate namespace and priority value in SIP signaling, and recognizes the need for priority treatment as specified in 3GPP TS 24.229 [17], the P-CSCF shall include the MPS-Identifier AVP and Reservation-Priority AVP in the AAR command towards the PCRF. The MPS-Identifier AVP shall contain the national variant for MPS service name indicating an MPS session. The Reservation-Priority AVP shall include the priority value of the related priority service. The Reservation-Priority AVP shall be populated with a default value if the priority value is unknown.

NOTE 1: Various mechanisms can be applied to recognize the need for priority treatment in the P-CSCF (e.g., based on the dialled digits), according to national regulation and network configuration, as stated in 3GPP TS 24.229 [17].

NOTE 2: Lowest user priority value is mapped in the corresponding lowest enumerated value of the Reservation-Priority AVP.

If the P-CSCF supports the Diameter message priority mechanism for an MPS session, it shall include the DRMP AVP towards the PCRF as described in 3GPP TS 29.213 [9], Annex J.

NOTE 3: If the P-CSCF supports the Diameter message priority mechanism for an MPS session, it includes the DRMP AVP with a priority value equivalent to the Reservation-Priority AVP priority value. Highest user priority value is mapped in the corresponding lowest enumerated value of the DRMP AVP.

Upon reception of a request that requires MPS treatment, the PCRF shall derive the PCC/QoS Rules corresponding to the MPS session, as appropriate. The PCRF shall take specific actions on the corresponding IP-CAN to ensure that the MPS session is prioritized, as described in 3GPP TS 29.212 [8], clause 4.5.19.1.3.

When the P-CSCF terminates the MPS session, the PCRF shall delete the PCC/QoS Rules corresponding to the MPS session. The PCRF shall revoke the actions related to the prioritization of the MPS session in the corresponding IP-CAN, as described in 3GPP TS 29.212 [8], clause 4.5.19.1.3.