Question: What is an appropriate use case for the private message mechanism in the UTRAN Iu interface RANAP signalling, according to 3GPP standards?
Option 1: Implementing standardized multivendor interoperable features required for basic network functionality.
Option 2: Deploying a new, widely adopted encryption algorithm across all vendors without prior standardization.
Option 3: Testing and evaluating a novel, vendor-specific scheduling algorithm before proposing it for standardization.
Option 4: Enhancing user equipment (UE) to support a non-standard, operator-exclusive service without affecting interoperability.
Explanation: The private message mechanism is intended for non-standard uses, such as vendor-specific features or research purposes, like testing new algorithms before they are considered for standardization. This aligns with Option 3, which involves evaluating a novel, vendor-specific scheduling algorithm prior to seeking standardization.