e ear- lier discussed Non-3GPP InterWorking Function (N3IWF) if it is implemented in the network and the UE is capable of sending the 5G NAS signaling via Wi-Fi. There is no data aggregation possible with this kind of interworking. So far, 3GPP is not planning to introduce any of the radio level Wi-Fi interworking solutions (which have been specified for LTE) in the 5G side in Release 15 or 16 scope. 0. PDU session exists 1.UE measurement report 2.) Handover required 3. SM context retrieved 4.Relocation request 5. SGW selection and bearer establishment (core and eNB) 7. Handover command 6.Relocation response 8.Handover command 9.Handover Complete 10.Handover Notify 11. MME informs SGW and bearers will be modified. Figure 5.16 5G to LTE inter-system handover. 5.6 Summary User plane Control plane 5G Control plane LTE LTE eNodeB 5G BTS LTE UE Option 3 UE Option 2 UE Figure 5.17 Example interworking between architecture options 2 and 3. When one considers the practical networks with option 3 and 2 enabled, the architec- ture looks as depicted in Figure 5.17, In this case, the gNB is acting both as the secondary cell for first phase UEs which are not expected to support other architecture alternatives as well as the primary cell for UEs which support standalone 5G operation. It is foreseen that some UE types, especially ones intended for services like URLLC operation, may end up supporting only standalone 5G operation. Similarly, the LTE eNB will support both legacy LTE-only UEs as well as UEs which support dual connectivity with 5G. 5.6 Summary The 5G radio operated with the 5G core enables many features beyond the capabili- ties of LTE, including the new flow-based QoS, support for local services, and network slicing. Further, the new core has been designed to enable support for the URLLC ser- vice, which allows the use of 5G to be expanded for industrial applications in addition to many other use cases. The overall architecture has been designed to enable cloud-native implementation, not only for the core but also 