Question: What should a 5G system do when a roaming User Equipment (UE) activates a service/application requiring a network slice not offered by the serving network but available in the area from other networks?
Option 1: The 5G system should deny access to the UE.
Option 2: The Home Public Land Mobile Network (HPLMN) should provide the UE with prioritization information of the Visited Public Land Mobile Networks (VPLMNs) with which the UE may register for the network slice.
Option 3: The serving network should offer a different network slice to the UE.
Option 4: The UE should be redirected to a different area.
Explanation: According to the requirements, when a roaming UE activates a service/application requiring a network slice not offered by the serving network but available in the area from other networks, the HPLMN shall be able to provide the UE with prioritization information of the VPLMNs with which the UE may register for the network slice. This allows the UE to access the required network slice from another network.