Question: For Mission Critical (MC) services over a 5G system with EPS interworking, what is required for seamless session continuity, particularly for MCPTT services, during inter-system mobility between 5GC and EPC/E-UTRAN?
Option 1: Support for dual-registration of MC service UEs on both 5GS and EPS simultaneously.
Option 2: EPS interworking with N26 interface (between AMF in 5GC and MME in EPC).
Option 3: Mandatory handover from 5GC to EPC/E-UTRAN for all MCPTT services.
Option 4: Dynamic adjustment of QoS parameters based on the UE's registered network.
Explanation: Seamless session continuity for MC services like MCPTT during inter-system change between 5G Core Network (5GC) and Evolved Packet Core (EPC)/Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) requires efficient communication between the two systems. The N26 interface, connecting AMF in 5GC with MME in EPC, is crucial for uninterrupted service continuity during mobility between these networks.