Question: What information should be included in the IP-CAN establishment/modification request message sent from PCEF to PCRF over the Gx reference point when a UE accesses via WLAN with GTP?
Option 1: UE local IP address and UDP port number (if available), plus the WLAN Access Point's MAC address
Option 2: UE local IP address and UDP port number (if available)
Option 3: H(e)NB local IP address, UDP port number, and UE's IMSI
Option 4: Only the UDP port number (if available), without the UE’s IP address
Explanation: According to the enhanced specification for the Gx reference point, when a UE accesses via WLAN with GTP, the IP-CAN establishment/modification request message from PCEF to PCRF should include the UE local IP address and the UDP port number, if these details are available. This ensures that the PCRF has sufficient information for policy and charging control decisions without requiring additional, unspecified parameters like the Access Point's MAC address or the UE's IMSI in this context.