Question: In an IMS (IP Multimedia Subsystem) environment, when a user accesses IMS services over a PS (Packet Switched) network that doesn't support full duplex speech or video media flow, which of the following session scenarios MUST be supported according to specified procedures?
Option 1: Only Basic voice origination and terminating sessions
Option 2: Voice origination with Communication Barring services, but not termination
Option 3: All of - Basic voice/video service sessions, sessions with Line ID/Communication Barring/Communication Diversion services, mid-call services, and communication services setting modifications
Option 4: None of the above; only data services are supported in such a PS network
Explanation: This option is correct because when an IMS service is accessed over a network that doesn't support full duplex media flow (like some PS networks or CS networks), the system still needs to facilitate a wide range of services to ensure user experience isn't severely impacted. This includes not just basic voice/video sessions, but also more complex services like those involving Line ID, Communication Barring, Diversion, mid-call features (e.g., Hold/Resume, Conferencing), and the ability to modify communication service settings. Supporting all these scenarios ensures a comprehensive IMS experience despite network limitations.