Question: What is the outcome when a Private User Identity is de-registered in the IMS, specifically regarding its associated Public User Identities?
Option 1: Only the explicitly registered Public User Identity linked to the Private User Identity is de-registered.
Option 2: All corresponding Public User Identities associated with the de-registered Private User Identity are also de-registered, both in the HSS and S-CSCF.
Option 3: The de-registration of a Private User Identity has no impact on its associated Public User Identities.
Option 4: Only the implicitly registered Public User Identity set is de-registered, not affecting explicitly registered Public User Identities.
Explanation: When a Private User Identity is de-registered, it implies the de-registration of all its associated Public User Identities. This ensures consistency across the network, specifically within both the HSS (which stores subscriber data) and the S-CSCF (which manages sessions), highlighting the interconnected nature of user identities in telecom networks and the importance of synchronized management to maintain service integrity.