Question: What is the primary purpose of the Retry-Interval AVP (AVP code 541) in the context of communication between the AF and PCRF over the Rx reference point?
Option 1: To specify the maximum number of retries for sending service information to the PCRF.
Option 2: To indicate the preferred IP-CAN session duration for a user.
Option 3: To notify the AF about congestion status changes in the cell.
Option 4: To define a time interval (in seconds) for the AF to wait before retrying to send temporarily rejected service information to the PCRF.
Explanation: The correct answer is Option 4 because the Retry-Interval AVP specifically serves to inform the AF how long to wait before reattempting to send service information that was initially rejected by the PCRF, such as during periods of cell congestion. This mechanism helps in managing network load and ensuring efficient communication between network elements.