Question: In a 5G network, when "5G NSWO support" (Service n°142) is not available on the USIM and the SUPI type is IMSI, how does the Mobile Equipment (ME) construct the SUCI in NAI format for authentication?
Option 1: The ME uses the entire SUCI calculated by the USIM as both the realm and username parts of the NAI.
Option 2: The ME constructs the realm part using a randomly generated identifier and the username part from the complete SUCI received from the USIM.
Option 3: The ME only uses the Home Network Identifier from the USIM for the realm, omitting the username part in the NAI format.
Option 4: The ME constructs the realm part of the SUCI using the Home Network Identifier from the USIM and the username part from the complete SUCI excluding the Home Network Identifier.
Explanation: This is correct because, when "5G NSWO support" is not available and the SUPI type is IMSI, the ME must construct the NAI format by separating the realm (using the Home Network Identifier) from the username part (derived from the complete SUCI excluding the Home Network Identifier), ensuring proper formatting for authentication in a 5G network under these conditions.