ocedure and supports various QoS characteristics with guaranteed bit rate. Bearer establishment negotiations are performed between the UE and the access point name (APN) 59 in the core network which maps the bearers to an external network such as the Internet or an IP multimedia subsystem (IMS). However, it is important to note that the availability and provisioning of bearers is strictly controlled by operator configuration, as well as the association between the UE and the PDN that provides PDU connectivity ser- vice. The PDU sessions can be based on IPv4, IPv6, Ethernet or unstructured. In NR and as shown in Fig. 1.58, the UE receives services through a PDU session, which is a logical connection between the UE and the data network. Various PDU session types are supported, for example, IPv4, IPv6, and Ethernet. Unlike the EPS, where at least one default bearer is always created when the UE attaches to the network, 5GS can establish a session Access point name is a gateway or anchor node between a mobile network and another IP network such as the Internet. A mobile device attempting a data connection must be configured with an access point name to present to the carrier. The carrier will then examine this identifier in order to determine what type of network connection should be created, which IP addresses should be assigned to the wireless device, and which secu- rity methods should be used. Therefore, the access point name identifies the packet data network with which a mobile data user communicates. The IP multimedia subsystem is an architectural framework developed by 3GPP for delivering IP multimedia services. Mobile networks originally provided voice services through circuit-switched networks and later migrated to all-IP network architectures. IP multimedia subsystem provides real-time multimedia sessions (voice over IP, video, teleconferencing, etc.) and nonreal-time multimedia sessions (push to talk, presence, and instant messaging) over an all-IP network. IP multimedia subsystem enables convergence of s