A 5G communication system includes at least one visited network slice; a home network slice; and a bridge entity. The at least one visited network slice comprises a visited radio access network (RAN) entity. The home network slice comprises a home Access and Mobility Management Function (AMF) entity. The bridge entity coupled between the visited RAN entity and the home AMF entity, wherein the bridge entity is configured to route a registration request message of a roaming user equipment (UE) received from the visited RAN entity to the home AMF entity.