Question: In a scenario where a change of Radio Access Technology (RAT) occurs without S-GW relocation, how does the BBERF (Bearer Binding and Event Reporting Function) notify the Policy and Charging Rules Function (PCRF) about the RAT type change?
Option 1: Through an event report sent directly to the PCEF (Policy and Charging Enforcement Function), bypassing the PCRF.
Option 2: By including the RAT type change as a parameter in an event report sent from the BBERF to the PCRF, which then forwards it to the PCEF.
Option 3: Via a dedicated RAT Change Notification message from the BBERF to the PCRF, not associated with an event report.
Option 4: Through a Request Bearer Resource Allocation procedure initiated by the S4 SGSN.
Explanation: This is correct because when a change of RAT without S-GW relocation occurs, the BBERF signals the RAT type change as a parameter in an event report sent from the BBERF to the PCRF, and then the PCRF sends another event report indicating the RAT type change to the PCEF, ensuring all relevant network functions are informed for proper resource allocation and policy enforcement.