Question: What is the primary purpose of the Security-Parameter-Index AVP (AVP code 1056) in Policy and Charging Control (PCC) as per 3GPP standards?
Option 1: To specify the Quality of Service (QoS) parameters for a particular IP flow.
Option 2: To identify the type of mobile radio interface used by the User Equipment (UE).
Option 3: To contain the security parameter index of an IPSec packet, ensuring secure data transmission.
Option 4: To define the charging rules for a specific Application Server in the network.
Explanation: The correct answer is Option 3 because the Security-Parameter-Index AVP is specifically designed to hold the security parameter index of an IPSec packet, which is crucial for securing IP communications within telecom networks. This aligns with the need for secure data transmission in various access types, as hinted at in the context of PCC and IPSec protocols.