Question: In a 5G System (5GS) supporting Fixed Network-Broadband Access Gateway (FN-BRG), what is a characteristic of the SUPI that corresponds to the SUCI provided by the W-AGF to the 5GC for FN-BRG?
Option 1: The SUPI always contains an IMSI, and its structure does not vary based on operator configuration.
Option 2: The SUPI contains a Globally Unique Line Identifier (GLI), with the realm part being an identifier of the operator owning the subscription.
Option 3: The SUPI never includes a GLI; it only comprises an IMSI for identification purposes in FN-BRG scenarios.
Option 4: The SUPI's structure for FN-BRG is not dependent on operator configuration and always includes both IMSI and GLI.
Explanation: In the context of 5GS with FN-BRG support, when a SUCI is provided for FN-BRG, it corresponds to a SUPI containing a Globally Unique Line Identifier (GLI), structured as a Network Access Identifier (NAI) where the user part is the GLI, and the realm part identifies the operator owning the subscription, enabling pseudonymization through the SUCI while allowing mapping to the actual SUPI by the UDM.