How does the 5G Core network handle network slicing in multi-operator scenarios?

Network slicing is a key concept in 5G technology that allows the creation of multiple virtual networks on a shared physical infrastructure to meet diverse service requirements. In multi-operator scenarios, where multiple network operators are involved, coordination and interoperability become crucial. The 5G Core (5GC) network is designed to handle network slicing in such environments. Below is a technical explanation of how the 5G Core network achieves this:

1. Network Slice Selection and Configuration:
   • When a user or a service subscribes to a network slice, the 5G Core network needs to select an appropriate slice based on the service requirements. This involves considering factors like latency, bandwidth, reliability, and other specific service characteristics.
   • In a multi-operator scenario, operators may have agreements or policies on how network slices are allocated and configured. Network Slice Selection Function (NSSF) is responsible for selecting and configuring the appropriate slice.
2. Network Slice Instance:
   • Each network slice is considered as a separate logical instance with its own set of resources and configurations. These slices coexist on the same physical infrastructure, but they are isolated from each other, ensuring secure and independent operation.
3. Network Slice Subnet:
   • To handle multi-operator scenarios, the 5G Core introduces the concept of Network Slice Subnet (NSS). NSS represents a set of network functions and resources dedicated to a specific slice. It allows multiple operators to collaborate and share portions of the network infrastructure for a particular slice.
   • The Network Slice Subnet is responsible for connecting the different Network Slice Instances and ensuring proper isolation between slices.
4. Inter-PLMN Communication:
   • Public Land Mobile Network (PLMN) refers to the network infrastructure of a mobile operator. In multi-operator scenarios, communication between different PLMNs becomes crucial for end-to-end service delivery.
   • The 5G Core introduces Inter-PLMN communication interfaces, ensuring seamless interaction and coordination between slices belonging to different operators. This involves the exchange of signaling and user plane data between Network Slice Instances.
5. Policy and Charging Control (PCC):
   • PCC plays a crucial role in managing network resources and charging policies for different slices. In multi-operator scenarios, PCC must be capable of handling policies across different operators.
   • The 5G Core utilizes a unified policy framework that allows operators to define and enforce policies for their slices. This framework ensures consistency and coordination in policy enforcement across multiple slices.
6. Security Considerations:
   • Security is a critical aspect, especially in multi-operator environments. The 5G Core employs robust security mechanisms to ensure the integrity and confidentiality of data across different slices.
   • Security mechanisms such as authentication, authorization, and encryption are applied to protect communication within and between slices.
7. Service Continuity and Handovers:
   • In scenarios where a user moves across different network slices managed by different operators, seamless service continuity and handovers are essential. The 5G Core network is designed to manage these transitions efficiently, ensuring uninterrupted service for the end-user.