Question: In the context of End-to-end Quality of Service (QoS) signalling flows, what is the primary action taken by the Policy Decision Function (PDF) upon approving a QoS Commit for previously disabled IP flow(s) or media components that are being resumed?
Option 1: The PDF sends a Diameter AAA to the Application Function (AF) to request additional authorization.
Option 2: The PDF sends COPS DEC message(s) to the Gateway GPRS Support Node (GGSN) to enable the use of authorized QoS resources.
Option 3: The PDF notifies the User Equipment (UE) directly to adjust its transmission settings.
Option 4: The PDF delays the approval until receiving further confirmation from the AF.
Explanation: Upon approving a QoS Commit, especially for resuming previously disabled IP flows or media components, the PDF's primary action is to ensure the allocated QoS resources are enabled. This is achieved by sending COPS DEC message(s) to the GGSN, which then enables the use of the authorized QoS resources for the resumed flows or components, facilitating uninterrupted and high-quality media transmission as per the committed QoS parameters.