depend a lot on implementation and may vary vendor by vendor. As mentioned above, a network slice is identified by an S-NSSAI, which is a combination Mandatory SST (Slice/Service Type) field, which identifies the slice type and consists of 8 bits (with range is 0-255); Optional SD (Slice Differentiator) field, which differentiates among Slices with same SST field and consist of 24 bits. The network may support a large number of NSSAIs, while a UE should not support more than eight slices simultaneously. 3.3.5.3 Virtualization Generally, all 3GPP network nodes can be virtualized, which has been the case in many EPC (i.e. core network) implementations. In 5G, the 5GC core network has been designed from the beginning with virtualization in mind (as explained in Section 3.2). In order to work effi- ciently with virtualized 5GC and also to support virtualization of NG-RAN network nodes, certain functionality has been added to NG-RAN interfaces. In particular, and in contrast to LTE, all NG-RAN network interfaces (NG, Xn, F1, and E1) support dynamic addition and removal of multiple SCTP endpoints on each termination point of each interface. This facilitates certain types of virtualized deployments, in which new computational and transport network resources may be added or removed dynami- cally - since in some case some of these resources may use a different transport network (i.e. IP) address, NG-RAN and 5GC support that in a manner which does not disrupt UE operation. More details about NG-RAN virtualization can be found in Section 6.2. Those details have, however, little protocol impact. 3.3.5.4 Non-3GPP Access Integration with non-3GPP access technologies, IEEE 802.11 (WLAN) in particular, is not new to 5G - various solutions have been defined by 3GPP in the past. For example, integra- tion of WLAN with LTE was enabled at core network and RAN levels. References In 5G, 3GPP made an attempt to make the NG network interface "access-agnostic," SO that from the point of view of 5GC a "common core" can be used with 3GPP N