Question: In a Sponsored Data Connectivity scenario, as per 3GPP standards, which AVP is used by the Policy and Charging Rules Function (PCRF) to report measured usage to the Application Function (AF), with possible reporting metrics including total octets, input octets, output octets, or time?
Option 1: Sponsor-Identity AVP
Option 2: Granted-Service-Unit AVP
Option 3: Used-Service-Unit AVP
Option 4: Sponsoring-Action AVP
Explanation: The correct answer is the Used-Service-Unit AVP. According to the 3GPP standards for Sponsored Data Connectivity, the PCRF utilizes this AVP for reporting measured usage back to the AF, including metrics like total octets, input octets, output octets, or time. The other options are incorrect because Sponsor-Identity AVP identifies the sponsor, Granted-Service-Unit AVP sets usage thresholds, and Sponsoring-Action AVP enables/disables sponsored data connectivity.