Question: In an IMS Centralized Services (ICS) architecture, when a User Equipment (UE) uses a Circuit Switched (CS) access network for media bearer, what is utilized to establish the media bearer for IMS sessions?
Option 1: Packet Switched (PS) Core Network
Option 2: CS Core Network
Option 3: IMS Application Server directly
Option 4: UE's Local Media Handler
Explanation: According to ICS principles, when a CS access network is used (or a PS network without full duplex support for speech/video), the **CS Core Network** is utilized to establish a circuit bearer for IMS session media. This ensures compatibility and service continuity for IMS services over CS accesses, leveraging the CS core's capability to handle circuit-switched media efficiently.