network slicing support [74]. network slice types. An NSI may contain different types of access nodes, such as 3GPP new RAT and a non-3GPP RAT. Consolidating fixed and wireless access in 5G is a desirable approach, which also requires further enhancements in the architecture design [74]. According to 3GPP specifications [3,16], a network slice always consists of an access and a core network part. The support of network slicing relies on the principle that traffic for dif- ferent slices is handled by different PDU sessions. Network can create different network slices by scheduling and also by providing different L1/L2 configurations. The UE should be able to provide assistance information for network slice selection in an RRC message. While the network can potentially support a large number of slices, the UE does not need to support more than eight slices in parallel. As we mentioned earlier, network slicing is a con- cept that allows differentiated network services depending on each customer requirements. The mobile network operators can classify customers into different tenant types each having different service requirements that control in terms of what slice types each tenant is autho- rized to use based on service-level agreement and subscriptions. Network slices may differ depending on the supported features and optimization of the net- work functions. An operator may opt to deploy multiple NSIs delivering exactly the same features but for different groups of UEs. A single UE can simultaneously be served by one or more NSIs via NG-RAN. A single UE may be served by a maximum of eight network slices at any time. The access and mobility management function (AMF) instance serving the UE logically belongs to each of the NSIs serving the UE, that is, this AMF instance is common 5G Network Architecture 41 Slice specific 5GC functions NSSAI 1 S-NSSAI X Control plane NSSAI 1, S-NSSAI X User plane Access node Slice specific 5GC functions S-NSSAI NSSAI 2, S-NSSAI y User plane Control plane User plane Control plane NSSA