Question: What is a permissible action for an HSS (Home Subscriber Server) to temporarily revoke an application-specific User Security Setting (USS) from the Generic User Security Settings (GUSS)?
Option 1: The HSS permanently deletes the application-specific USS from the GUSS and notifies all affected NAFs.
Option 2: The HSS temporarily removes the application-specific USS from the GUSS, with updates to the BSF occurring upon session timeout or initiation of a new bootstrapping session.
Option 3: The HSS modifies the subscriber's profile to deny access to all applications until further notice, without altering the GUSS.
Option 4: The HSS sends a direct revoke command to the UE, bypassing the NAF and BSF.
Explanation: This option aligns with the specified behavior in the context of temporarily revoking an application-specific USS, as it allows for the HSS to remove the USS without immediate impact on the BSF, which updates upon session timeout or a new bootstrapping session. This approach supports temporary service revocation without necessitating immediate changes across all network elements.