Question: In the context of IP Multimedia Subsystem (IMS) procedures, when a User Equipment (UE) is roaming, how do the procedures differ based on the location of the Proxy-Call Session Control Function (P-CSCF)?
Option 1: Procedures are entirely different for both home and visited network P-CSCF locations, with unique steps for each scenario.
Option 2: The location of the P-CSCF does not affect IMS procedures during roaming; all scenarios follow the same process.
Option 3: For roaming users, IMS procedures are simplified when the P-CSCF is in the visited network compared to being in the home network.
Option 4: When a user is roaming and the P-CSCF is located in the home network, the IMS procedures closely resemble those of a non-roaming user.
Explanation: This answer reflects an understanding of how IMS procedures adapt to different network configurations during roaming scenarios. Specifically, it highlights that when the P-CSCF is located in the home network (even for a roaming user), the system behaves similarly to how it would for a non-roaming user, emphasizing continuity and consistency in service provision across different geographical locations.