ork slice instance (NSI) layer, and (3) resource layer. The service instance layer represents the services (end-user or business services) which are supported by the network where each service is represented by a service instance. The services are typi- cally provided by network operator or a third party. A service instance can either represent an operator service or a third-party service. A network operator uses a network slice blue- print2 to create an NSI. An NSI provides the network characteristics which are required by Network slice blueprint is a complete description of the structure, configuration, and the plans/workflows for how to instantiate and control a network slice instance during its lifecycle. A network slice blueprint enables the instantiation of a network slice, which provides certain network characteristics (e.g., ultralow latency, ultrareliability, and value-added services for enterprises). A network slice blueprint refers to required physi- cal and logical resources and/or to sub-network blueprint(s). 5G Network Architecture Service Service Service Service Service Service instance 1 instance 2 instance 3 instance 4 instance 5 instance layer Network slice instance layer network network network network instance instance instance instance Resource layer Resource/network infrastructure/network functions Figure 1.16 Network slicing conceptual architecture [6]. a service instance. An NSI may also be shared across multiple service instances provided by the network operator. The NSI may be composed of zero or more sub-network instances, which may be shared by another NSI. Similarly, the sub-network blueprint27 is used to cre- ate a sub-network instance to form a set of NFs, which run on the physical/logical resources. The sub-network instance is a set of NFs, which run on the physical or logical resources. The network slice is a complete logical network providing telecommunications services and network capabilities. Network slices vary depending on the features of the ser- vice they need to support. 