Question: What action does the NG-RAN take when it determines that the Guaranteed Flow Bit Rate (GFBR), Packet Delay Budget (PDB), or Packet Error Rate (PER) of a QoS profile cannot be fulfilled, and Alternative QoS Profile handling is supported?
Option 1: The NG-RAN sends a notification to the SMF indicating that the GFBR can no longer be guaranteed, along with a reference to the matching Alternative QoS Profile with the highest priority.
Option 2: The NG-RAN releases the NG-RAN resources for this GBR QoS Flow without sending any notification to the SMF.
Option 3: The NG-RAN tries to fulfill the lowest priority Alternative QoS Profile and sends a notification to the SMF only if it cannot be fulfilled.
Option 4: The NG-RAN does not take any action and continues to try to fulfill the original QoS profile.
Explanation: According to the text, when the NG-RAN determines that the GFBR, PDB, or PER of a QoS profile cannot be fulfilled, it sends a notification to the SMF indicating that the GFBR can no longer be guaranteed. Before sending this notification, the NG-RAN checks whether the currently fulfilled values match any of the Alternative QoS Profiles in the indicated priority order. If there is a match, the NG-RAN includes a reference to the matching Alternative QoS Profile with the highest priority in the notification.