Question: When a Mission Critical (MC) service user migrates to a partner MC system using a different Public Land Mobile Network (PLMN) than their primary MC system, what additional requirement must be met between the two PLMNs for seamless service access?
Option 1: Only APN provisioning for the partner MC system's PDNs on the primary MC system's EPS subscriptions.
Option 2: Only local break-out enablement for the partner MC system's specified APNs in the partner MC system's PLMN.
Option 3: Both EPC-level roaming and local break-out enablement for specific APNs, but without needing to provision EPS subscriptions with new APNs.
Option 4: EPC-level roaming between the two PLMNs, local break-out enablement in the partner MC system's PLMN for specified APNs, **and** provisioning of those APNs (including access credentials) on the primary MC system's utilized EPS subscriptions.
Explanation: For a seamless migration experience when the partner and primary MC systems use different PLMNs, three key technical requirements must be fulfilled: EPC-level roaming ensures connectivity between the two networks. Local break-out enablement in the partner's PLMN for specific APNs allows direct access to the partner's services without unnecessary backhauling. Provisioning of EPS subscriptions with the partner's APNs (including necessary access credentials) on the primary MC system's utilized subscriptions ensures migrating users can authenticate and access new services without additional setup, addressing security, service delay, and user experience concerns.