Question: What is a key requirement for the GPRS-IMS-Bundled Authentication (GIBA) solution in terms of its relationship with the fully compliant IMS security solution?
Option 1: To completely replace the fully compliant IMS security solution for long-term use.
Option 2: To allow for smooth and cost-effective migration to the fully compliant IMS security solution.
Option 3: To restrict charging models to only prepaid services.
Option 4: To eliminate support for early IMS UEs after fully compliant UEs are deployed.
Explanation: The correct answer, Option 2, reflects the requirement that the GIBA solution should serve as an interim measure, facilitating a seamless and economically viable transition to the fully compliant IMS security solution once suitable products become available. This ensures that security can be enhanced without disrupting service or incurring excessive costs. The other options are incorrect because they either contradict the stated requirements (Options 1 and 4) or introduce unrelated restrictions (Option 3).