Question: When the PCRF receives an indication that IMS Signalling Priority is active for an IP-CAN session, what actions does the PCRF take regarding the ARP (Allocation and Retention Priority) settings?
Option 1: The PCRF only sets the ARP of all PCC rules assigned to the IMS signalling bearer to a default value.
Option 2: The PCRF sets the ARP of the default bearer as appropriate for the prioritized service, and if required, adjusts the ARP of PCC rules for IMS signalling and derives new PCC Rules based on received Rx information.
Option 3: The PCRF deletes all existing PCC Rules and provisions the PCEF with new QoS information applicable only to non-priority services.
Option 4: The PCRF takes no action regarding ARP settings until the MPS session is terminated.
Explanation: When IMS Signalling Priority becomes active, the PCRF must ensure that both the default bearer and any relevant PCC rules (including those for IMS signalling) are configured to prioritize the service appropriately. This involves setting or adjusting the ARP values as necessary to reflect the prioritized status of the service, based on the information received. This action is crucial for maintaining Quality of Service (QoS) for priority multimedia services over the network.