Question: What action does the SMF take when the last PDU Session for a 5G VN group is released on a UPF?
Option 1: The SMF creates a new group-level N4 Session in the UPF.
Option 2: The SMF updates the N4 rules related to the UE address in the group-level N4 Session context.
Option 3: The SMF may delete the group-level N4 Session in the UPF and release the N19 tunnel(s) between this UPF and other UPF(s) serving the 5G VN group via update of the corresponding N4 rules.
Option 4: The SMF allocates new N19 tunnel resources for the 5G VN group.
Explanation: When the last PDU Session for a 5G VN group is released on a UPF, the SMF may delete the group-level N4 Session in the UPF and release the N19 tunnel(s) between this UPF and other UPF(s) serving the 5G VN group via update of the corresponding N4 rules. This action is necessary to free up resources and maintain efficient network operation.