# Towards Efficiently Provisioning 5G Core Network Slice Based on Resource and Topology Attributes
## 1 Introduction  
Information and communication technologies (ICTs) are infiltrating many fields, including governance, economics, defense, media, social media, health care, industry, education, etc. [1; 2; 3; 4]. These fields are undergoing continuous digitalization and pervasive interconnection, making communication networks an indispensable infrastructure. The coming 5G networks will promote the further upgrade of human interaction. More importantly, 5G will support a variety of vertical services, such as self-driving cars, augmented reality, live video, telemedicine, and financial transactions [5]. While 5G will improve productivity and optimize business processes, it will inevitably bring new legal and ethical issues that cannot be ignored [6; 7]. The 5 th generation (5G) mobile networks are expected to handle the tremendous growth of data from diverse and heterogeneous services. Softwarization, virtualization, and cloud-based5G architecture design [8; 9] are considered to be promising technologies to address the challenges introduced by the diversified service demands. Network slicing is one of the key concepts that can be realized by these techniques to support the specific needs of vertical industries. End-to-end network slicing enables multiple network services to share a single physical network infrastructure (also called the substrate network) including radio access networks (RAN) and core networks [10; 11]. The big idea behind network slicing is to allow the shared 5G physical network infrastructure to be _sliced_ into multiple logical networks, each of which is a collection of virtual computing and networking resources capable of supporting a specific type of service. It is, therefore, believed that network slicing will be an indispensable enabler of 5G network architecture to meet the diverse requirements of vertical applications. We can broadly divide network slicing into two categories: radio access network slicing and core network slicing. In this paper, we focus on 5G core network slicing. A three-layer 5G core network slicing system model proposed by us has been elaborated in [12] and illustrated in Figure 1. There are three administrative roles in this model: 5G core infrastructure provider, 5G core slice provider, and slice tenants. The Infrastructure Provider (InP) owns the 5G core infrastructure and can lease physical resources such as computing and networking resources to the slice providers. A Slice Provider (SP) can be regarded as a virtual telecommunications service provider (TSP). The SP controls the virtualization of the resources to form network slices and provides services for users. Slice tenant is the consumer of an application specific network slice. It informs the slice provider of the characteristics of the service it needs. The slice provider requests physical resources from the infrastructure provider to create a network slice to provide the service according to the tenant's demands. The slice provisioning system interacts with the three roles to orchestrate and manage physical resources. Although network slicing has attracted increasing attention from both academia and industry [13], slice provisioning is a key issue to be addressed [14]. Slice provisioning is an approach to creating separate virtual networks based on service requirements using common physical computing and networking resources. Two sub-tasks in slice provisioning are slice node provisioning and slice link provisioning. From the perspective of InP, since the computing and networking capacities of the  
Figure 1: Illustration of three-layer 5G core network slicing system model. physical network are limited, increasing physical resource utilization to provision more slices is crucial to raising its revenue. Therefore, in this article, we study how to efficiently provision 5G core network slices to optimize resource utilization of the 5G physical network infrastructure, thus, increasing the revenue of InP.