Question: When a BBERF (ePDG) detects NAT in a WLAN scenario (case 2a or case 2b), what information MUST it report to the PCRF over the Gxx reference point for Bearer Binding?
Option 1: UE's Local IP address only
Option 2: ePDG IP address and UDP source port number only if NAT is detected
Option 3: UE's Local IP address, UDP source port number (if NAT is detected), and ePDG IP address
Option 4: None of the above; only the detection of NAT is reported
Explanation: In WLAN scenarios (case 2a and case 2b) where NAT is detected, the BBERF (ePDG) is required to provide detailed information for proper bearer binding management. This includes the UE's Local IP address for identification, the UDP source port number to handle NAT implications, and the ePDG IP address for routing purposes. Reporting all three ensures comprehensive support for PCC (Policy and Charging Control) over the Gxx reference point, facilitating efficient network resource allocation and traffic management.