###### Abstract  
Network segregation is the solution adopted in the IMT-2020 standardization of the International Telecommunications Union (ITU), better known as 5G networks (Fifth Generation Mobile Networks), under development to meet the requirements of performance, reliability, energy, and economic efficiency required by applications in the various verticals of current and near-future economic activities. The philosophy adopted for the IMT-2020 standardization relies on the use of Software-Defined Networking (SDN), Network Function Virtualization (NFV), and Software-Defined Radio (SDR), i.e., the _softwarization_of the network. Softwarization allows network segregation through its slicing, which is discussed herein this work. Network slicing is performed by a novel Orchestrator, as provided in IMT-2020, which maintains the end-to-end network slices independent of each other and performs horizontal handover when the possibility of a loss of Quality of Service (QoS) is predictively detected by monitoring quality parameters during operation. Therefore, the Orchestrator is dynamic, operates in uptime, and allows horizontal handover. Hence, it chooses the most appropriate telecommunication infrastructure provider and network operator to guarantee QoS and Quality of Experience (QoE) to end-users in each network segment. These features make this work modern and keep it aligned with the actions being carried out by ITU. Based on this objective, as the main result of this paper, we propose an effective architecture for implementing the Orchestrator, not only to contribute to the state of the art for 5G and beyond communication systems but also to generate economic, technological, and social impacts. 5G and beyond; distributed cloud computing; multi-provider orchestration; networks softwarization; V2X +
Footnote †: journal: Applied Sciences  
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Footnote †: journal: Applied Sciences  
high broadband Internet speeds (greater than 1 Gbps), low latency (1 ms) [12; 13], and high reliability (99.9999%) [13], providing profound transformations in several industries, in addition to enabling the emergence of business models that would currently be unfeasible at the hospital, logistical, vehicle traffic levels, and so on [14]. Among the applications of great relevance to 5G, we can mention: autonomous driving by vehicles connected virtually and logically (Vehicle-to-Everything (V2X)) by tactile Internet. That is, in the broadest sense, 5G will provide better and greater connectivity between mobile and/or even fixed devices [15]. However, to use of all the network resources according to the end-users' demands, network slicing and orchestration are essential [16]. The new scenarios have strict and heterogeneous requirements to be achieved by improvements to the Radio Access Network (RAN) and a collection of innovative wireless technologies [17]. Software improvements, such as Software-Defined Radio (SDR), Software-Defined Networking (SDN), and Network Function Virtualization (NFV), will play a vital role in the integration of these different technologies [18; 19]. In addition, the access networks and 5G radio core will be based on a virtualized SDN/NFV infrastructure, which will orchestrate resources and control the network, to provide network services in an efficient, flexible, and scalable manner. A Network Slice (NS) is an important complex attribute of 5G networks [20]. According to NGMN [21], an NS is defined as a set of network functions and resources to run them, forming a complete instantiated logical network to meet specific network characteristics required by the Service Instance(s). This work presents the fundamentals of network slicing and orchestration, highlighting the challenges for slice management.