Question: For a UE (User Equipment) supporting CSFB (Circuit Switched Fallback) to UTRA, what is the RRC (Radio Resource Control) message requirement for High Priority CSFB redirection?
Option 1: Mandatory support for RRCConnectionRelease with 'cs-FallbackHighPriority' indication
Option 2: Optional support for RRCConnectionSetup with 'cs-FallbackNormalPriority' indication
Option 3: Conditional support for RRCConnectionReconfiguration with 'cs-FallbackLowPriority' indication
Option 4: No specific RRC message requirement for High Priority CSFB redirection
Explanation: In the context of High Priority CSFB to UTRA for UEs that support this feature, ensuring timely and reliable fallback is crucial. The RRCConnectionRelease message with a 'cs-FallbackHighPriority' indication is specifically designed to handle such scenarios efficiently. Mandatory support for this message ensures that all compliant UEs can effectively utilize high-priority CSFB when necessary, aligning with the performance and functionality expectations of modern telecommunications networks.