se when RAN sharing with multiple cell IDs is deployed. 3.3.5.2 Slicing Slicing is an important feature of 5G, which spans across an operator's network, including RAN, as shown in Figure 3.3.10. It is generally assumed that a slice "tenant" will have a SLA with an operator to lease parts of an operator's network, including RAN and radio resources. It is then up to an LOBAL INITIATIVE Smartphone Slice 1 (e.g. for the network operator's subscribers) Smartphone Slice 2 (e.g. for a virtual operator's subscribers) Vehicle Services Slice 1 (e.g. for a truck manufacturer's fleet assistance) M2M Service Slice 1 (e.g. for a goods or container tracking system) Overall operator network (PLMN) domain (Radio) Access Data Network UE domain Network domain Core Network domain /applications Figure 3.3.10 Example of network slicing. 3 5G System Overview operator's policy and NG-RAN implementation to ensure that the SLA is fulfilled. For example, an NG-RAN implementation may need to provide resource isolation between different slices (if multiple slices are active at a time), which can be "soft isolation" or "hard isolation." However, from the NG-RAN architecture, network interfaces, and protocols, very little is specified, leaving plenty of room for implementation. During network interface (e.g. NG and Xn) setup, both network nodes (gNB and AMF or gNBs, respectively) exchange infor- mation about slices they support. A UE may provide to the network the NSSAI it selected using the RRCSetupComplete message. Subsequently, when a UE context is established in NG-RAN, the AMF indicates the list of allowed slices (e.g. allowed NSSAI) for the UE. This information is then used by NG-RAN, among other things, for: Selecting an AMF for a UE and routing the Initial UE message over the NG interface to an appropriate AMF that supports the slices requested by the UE; UE access control; Resource isolation between slices; UE mobility decisions. However, the actual logic to support the above is not specified. In the end, slicing function- ality will 