# A Virtualization Infrastructure Cost Model for 5G Network Slice Provisioning in a Smart Factory
## 1 Introduction  
Fifth generation mobile networks or 5G networks are a key enabler for industry verticals that require fast, secure, ultra-reliable, and low-latency communications. Industry verticals consist of diverse device types belonging to different use cases, which need to be provisioned over specialized network slices. Network slicing in 5G is enabled by Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) to logically isolate and provision required virtual network resources as end-to-end virtual network slices. NFV decouples the network functions from their dedicated network equipment and enables their operation as Virtual Network Functions (VNFs) on general-purpose server hardware [1]. Furthermore, SDN enables instantiating the VNFs as service-specific function chains. One of the main advantages of SDN in 5G comes from decoupling the User Plane (UP) and Control Plane (CP) VNFs for independent scalability and management [2]. The Control and User Plane Separation (CUPS) enables the separation and optimal placement of the UP and CP VNFs, which can be centralized in one location or optimally distributed to various locations, as required by the use cases [3]. Additionally, the UP and the CP can be deployed locally, enabling lower latencies and local processing of sensitive data for critical use cases such as manufacturing and public safety. Based on resource requirements derivedfrom the necessary data rate, latency, reliability, availability, and number of connected devices, use-case-specific slices can be provided to various industries. Mobile Network Operators (MNOs) have traditionally relied on adding more capacity and coverage to serve the increasing number of customers and have primarily served wide-area communications with cellular networks. On the other hand, local area communications have been dependent on wired or wireless connectivity such as Wi-Fi. The fourth industrial revolution is bringing together various industries through the integration of cyber-physical systems, digitalization of assets, Internet of Things, and the virtualization of networking devices over new communication technologies [4]. Local-area communications have become more critical as more industries are automating their processes, thus requiring better connectivity, mobility, and reliability. With a growing number of customers and varying connectivity requirements across different use cases such as enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), massive Internet of Things (mIoT), and Vehicle-to-anything (V2X) communications, it has become increasingly important to move towards more reliable wireless connectivity. In the beginning, 5G is rolled out as a non-standalone deployment, utilizing 5G New Radio (NR) in the access network but still relying on the 4G Evolved Packet Core (EPC). Such a non-standalone deployment offers the expected benefits in Radio Access Network (RAN), but a full end-to-end 5G network slicing requires the next generation virtualized 5G core network. A standalone 5G network provides significantly better performance in terms of latency as compared to non-standalone 5G and legacy 4G networks [5]. Thus, for stakeholders transitioning to a full end-to-end sliced 5G network, developing a cost model for the virtualization infrastructure in order to be able to provide network slices is essential. According to [6], the global network function virtualization market is expected to grow at a Compound Annual Growth Rate (CAGR) of 20.7%, reaching USD 59.1 billion in 2027. The global network slicing market is expected to reach USD 5.8 billion by 2025 and will be led by enterprise and industrial applications, followed by public safety [7]. The total global value of the addressable 5G-enabled market for service providers is expected to reach USD 700 billion in 2030 [8]. Such estimates point to the vast business potential to be unlocked; however, the commercial and technical demand for network slicing can vary for countries, industry verticals, and their use cases.