Question: In a non-3GPP access scenario, when is a Bearer Modification event generated in relation to the ePDG and PDN-GW, according to 3GPP security standards for lawful interception?
Option 1: Only when a new bearer is established at the PDN-GW without involving the ePDG.
Option 2: When a Bearer Modification is handled by the ePDG over GTP S2b interface or detected at the PDN-GW.
Option 3: Exclusively when the ePDG initiates a bearer modification without any change at the PDN-GW.
Option 4: Never, as Bearer Modifications in non-3GPP accesses do not trigger lawful interception events.
Explanation: This is correct because, according to the extracted context from 3GPP TS 33.107, a Bearer Modification event is specifically generated under two conditions: (1) when the ePDG handles a Bearer Modification over the GTP S2b interface, or (2) when such a modification is detected at the PDN-GW. This ensures that lawful interception mechanisms can capture and respond to changes in bearer configurations, whether initiated through the ePDG or observed at the gateway level.