Question: In a deployment scenario where an IMS Subscription Holder (ISH) is different from the administrative domain of a Standalone Non-Public Network (SNPN), what is required for a User Equipment (UE) to access both the SNPN's 5GS and IMS services?
Option 1: A single subscription with the SNPN, which implicitly grants access to IMS services.
Option 2: Two separate subscriptions: one for accessing the 5GS of the SNPN and another for accessing IMS services provided by the ISH.
Option 3: Authentication only in the SNPN domain, using credentials provided by the Credentials Holder (CH).
Option 4: A temporary shared subscription between the SNPN and ISH, valid only for the duration of the IMS service usage.
Explanation: When the IMS Subscription Holder (ISH) is independent from the SNPN's administrative domain, the UE must authenticate separately in each domain to access both services. Thus, having two distinct subscriptions—one for the SNPN's 5GS (potentially provided by the SNPN or a Credentials Holder) and one for IMS services with the ISH—is necessary for successful authentication and service access in this scenario. This setup ensures secure and authorized access to both the 5G network and the IMS services, each managed under different administrative domains.