Question: In a scenario where an MSC Server (enhanced with ICS and supporting I6) detects a CS emergency call from a registered UE without prior IMS registration using I2, how does the MSC Server handle the CS emergency call?
Option 1: The MSC Server performs an emergency registration to IMS via I2 and then proceeds with an emergency session establishment request to E-CSCF via I6.
Option 2: The MSC Server directly proceeds with an anonymous emergency request towards E-CSCF via I6, bypassing any registration procedure.
Option 3: The MSC Server initiates a standard CS call setup without involving IMS, treating it as a non-emergency call.
Option 4: The MSC Server falls back to the behavior of an MSC Server not enhanced for ICS in handling CS emergency calls.
Explanation: According to the specified procedure, if the UE has been registered with the MSC Server but not with IMS using I2, the MSC Server reverts to its non-ICS enhanced behavior for handling CS emergency calls. This ensures compatibility and functionality even without the enhanced IMS registration.