Question: In a Voice Call Continuity (VCC) scenario, what is the general principle regarding the applicability of CS-based and IMS-based supplementary services to a VCC subscriber?
Option 1: Both CS-based and IMS-based supplementary services are always available simultaneously to the VCC subscriber, regardless of the domain.
Option 2: The type of supplementary service (CS or IMS) that applies is determined by the subscriber's initial call setup technology (e.g., voice over LTE (VoLTE) or Circuit Switched (CS)).
Option 3: CS-based supplementary services apply only while the VCC subscriber is in the CS domain, and equivalent IMS-based services apply only while in the IMS domain.
Option 4: Supplementary service settings must always be synchronized between the CS and IMS domains for seamless service continuity.
Explanation: This option correctly reflects the principle outlined for supplementary services in a VCC scenario, ensuring consistency with the underlying communication infrastructure (CS or IMS) without requiring synchronization of service settings across domains. This approach supports a more flexible and domain-specific application of supplementary services, enhancing the overall user experience by maintaining service continuity to the greatest degree possible within each respective domain.