Question: In a 3GPP network, when a P-CSCF receives an authorized Resource-Priority header in SIP signaling for an MPS session, what information must it include in the command towards the PCRF to ensure priority treatment?
Option 1: Only the MPS-Identifier AVP with the national variant for MPS service name.
Option 2: Both the MPS-Identifier AVP (with the national variant for MPS service name) and the Reservation-Priority AVP (with a default value if the priority is unknown).
Option 3: The DRMP AVP alone, with a priority value equivalent to the lowest enumerated value for highest user priority.
Option 4: Neither MPS-Identifier nor Reservation-Priority AVPs are required; only QoS parameters need to be adjusted.
Explanation: To ensure proper handling and prioritization of an MPS session, the P-CSCF needs to inform the PCRF about both the nature of the session (via the MPS-Identifier AVP) and its priority level (via the Reservation-Priority AVP). This dual approach allows the PCRF to apply the correct policy and charging control rules, ensuring the session receives necessary prioritization. Including both AVPs is crucial for maintaining service quality as per specifications for MPS sessions.