1 Introduction

Network slices allow users to customize networks based on functionalities (such as mobility) and performance requirements (like latency, availability, and reliability). These slices differ in supported features and network function optimizations. Different network slices may have unique S-NSSAIs associated with varying slice and service types.

Users can deploy multiple instances of network slices that offer the same features but cater to different groups of User Equipments (UEs). Each instance provides tailored services for individual customers. Although the network slices may share the same slice or service type, they can have different slice differentiators within their respective S-NSSAIs. Oracle Communications Cloud Native Core's Network Slice Selection Function (NSSF) effectively determines the specific network function associated with a slice.

NSSF is a functional element that supports the following functionalities:

  • NSSF enables the Access and Mobility Management Function (AMF) to perform initial registration and Protocol Data Unit (PDU) session establishment.
  • AMF can retrieve NRF, NSI ID, and target AMFs as part of UE initial registration and PDU establishment procedure.
  • NSSF uses an NF Service Consumer (AMF) to update the S-NSSAI(s) that AMF supports and notifies of any changes in the status.
  • NSSF selects the network slicing instance (NSI) and determines the authorized Network Slice Selection Assistance Information (NSSAIs) and AMF to serve the UE.
  • NSSF interaction with NRF allows retrieving specific NF services to be used for registration request.

NSSF provides the following information when queried by the AMF:

  • Allowed NSSAIs
  • Configured NSSAIs
  • Restricted NSSAIs
  • Candidate AMF List (in case of registration)
  • Network Slice instance ID (for PDU session establishment)
  • Slice-level NSSF information (for PDU Connectivity)

NSSF supports the above functions through the following NSSF services:

  • NS Selection service (Nnssf_NSSelection): This service is used by an NF Service Consumer (AMF) to retrieve the information related to network slice. It enables network slice selection in the serving Home Public Land Mobile Network (HPLMN).
  • NS Availability Service (Nnssf_NSAvailability): This service stores and maintains list of supported S-NSSAIs per TA. It allows NF service Consumer (AMF) to update and subscribe the above data and get notifications for any addition or deletion of supported S-NSSAIs.

Note:

The performance and capacity of the NSSF system may vary based on the call model, Feature or Interface configuration, and underlying CNE and hardware environment.

1.1 Purpose and Scope

This document describes the measurements that are used to perform the performance evaluation of NSSF, microservices, and deployment environment setup software such as Aspen Service Mesh (ASM), Operations Services Overlay (OSO), Oracle Communications Cloud Native Core, Cloud Native Environment (CNE), and so on.

This document provides the following information:

  • Benchmark NSSF performance and capacity
  • Benchmark data from our labs
  • Key metrics used to manage NSSF performance and capacity

1.2 References

  • Oracle Communications Cloud Native Core, Network Slice Selection Function User Guide
  • Oracle Communications Cloud Native Core, Network Slice Selection Function Installation, Upgrade, and Fault Recovery Guide
  • Oracle Communications Cloud Native Core, Network Slice Selection Function Network Impact Report
  • Oracle Communications Cloud Native Core, Network Slice Selection Function Troubleshooting Guide