NG-RAN) and 3GPP 5GC network architecture and network interfaces are based on logical separation of signaling and data transport networks, as well as separation of NG-RAN and 5GC functions from the transport functions. As a result, the addressing schemes used in NG-RAN and 5GC are decoupled from the addressing schemes of the transport functions. The protocols over the air interface and the NG interfaces are divided into user-plane proto- cols, which are the protocols implementing the actual protocol data unit (PDU) session ser- vice, carrying user data through the access stratum (AS); and control-plane protocols, which are the protocols for controlling the PDU sessions and the connection between the user equipment (UE) and the network from different aspects, including requesting the service, controlling different transmission resources, handover, etc. [15]. 1.1.1 Network and Service Requirements The service-centric 5G network architecture has been designed to flexibly and efficiently meet diverse requirements of the emerging applications/services. With SDN and NFV sup- porting the underlying physical infrastructure, 5G network systematically centralizes access, transport, and core network components. Migration to cloud-based architectures is meant to support wide-ranging 5G services and enables key technologies, such as network slicing, on-demand deployment of service anchors, and component-based NFs. 5G Network Architecture 11 The design principles of 3GPP next-generation system architecture have deviated from those of the long-term evolution (LTE) evolved packet core (EPC) network in order to address the challenging requirements of 5G applications/services. While the design of 5G network started from a clean slate, the requirements for support of the new radio access technologies (RATs) as well as the evolved LTE, legacy systems, and non-3GPP radio access have caused the new design to borrow a large amount of concepts from the predecessor networks. Some of the key tenets of 5G network design include the require