Question: In a 5G network, when a SUPI contains a GCI, what is the recommended format for the 'realm' part of the NAI if the operator owns a PLMN ID?
Option 1: gci.globe.com
Option 2: 5gc.mnc<MNC>.mcc<MCC>.3gppnetwork.org (where <MNC> and <MCC> are replaced with actual values)
Option 3: operator.5g.net
Option 4: cellid.mobilebroadband.net
Explanation: According to specifications, the 'realm' part of the NAI for a SUPI containing a GCI should identify the operator owning the subscription. With a PLMN ID, the recommended realm format is standardized as `5gc.mnc<MNC>.mcc<MCC>.3gppnetwork.org`, replacing `<MNC>` and `<MCC>` with the actual Mobile Network Code and Mobile Country Code, ensuring a uniform and identifiable format across 5G networks.