Question: In a 5G System supporting Wireless and Wireline Convergence Access, what is the primary component of the Subscription Permanent Identifier (SUPI) for a 5G Broadband Residential Gateway (5G-BRG) when accessing a Public Land Mobile Network (PLMN)?
Option 1: MSISDN (Mobile Station International Subscriber Directory Number)
Option 2: External Identifier (e.g., an email address or URL)
Option 3: Temporary Mobile Subscriber Identity (TMSI)
Option 4: International Mobile Subscriber Identity (IMSI)
Explanation: In the context of 5G System architecture, particularly for PLMNs and devices like a 5G-BRG, the SUPI is crucial for identifying subscribers. The IMSI is a unique identifier for each mobile subscriber and is used in various network architectures for authentication and billing purposes. Given the requirement for secure and standardized identification, an IMSI is the most appropriate and specified component of the SUPI for accessing PLMNs with a 5G-BRG, ensuring seamless integration into existing mobile network infrastructures.