Question: In a two Core Network domain architecture, where does the primary responsibility for Paging Co-ordination Function lie, and what identifier is utilized for this purpose within UTRAN?
Option 1: Primarily in UTRAN, utilizing the Common ID provided by the CN.
Option 2: Exclusively in CN, with the RNC (Radio Network Controller) ID being used.
Option 3: Jointly between UTRAN and CN, with IMSI (International Mobile Subscriber Identity) as the key identifier.
Option 4: Solely in the UE (User Equipment), leveraging the TMSI (Temporary Mobile Subscriber Identity).
Explanation: In a two Core Network domain architecture, to manage paging efficiently when a UE has a signaling connection to one CN node but is paged by another, the UTRAN takes primary responsibility for Paging Co-ordination. This function utilizes a Common ID, provided to the UTRAN by the CN, ensuring coordinated paging across different domains without relying on UE-specific or RNC-specific identifiers directly for this coordination.