NSSF Architecture
NSSF comprises of various microservices deployed in Kubernetes based Cloud Native Environment (CNE, example: OCCNE). Some common services like logs or metrics data collection, analysis and graphs or charts visualization, etc. is provided by the environment. The microservices integrates with them and provide them necessary data. The following diagram describes the overall architecture of the NSSF:
Figure 3-1 Network Slice Selection Function Architecture Diagram
The architecture has the following components:
NS Selection Microservice
This microservice receives all NS-Selection requests and provides network slice information.
NS Availability Microservice
This service supports the NS-Availability service of NSSF and stores subscriptions and AMF data.
NS Subscription Microservice
This microservice sends notifications based on subscribed events through NS Availability. Notifications are sent to subscribed AMFs to signify changes in authorization state with respect to S-NSSAIs on TAI as per 3GPP TS 29.531.
NS Configuration Microservice
This microservice is responsible for configuring policy rules. This microservice implements a REST messaging server that receives configuration HTTP messages, validates and stores the configuration in the database.
NRF Client Microservice
- NRF Registration and Heartbeat: First the Registration profile is configured using helm. Then the Performance service calculates load and capacity of NF. NS Registration requests load and capacity from performance service and send it to NRF with heartbeat.
- NRF Subscription: NSSF subscribes to NRF for AMF based on Target AMF Set and Region ID for Registration and Deregistration and load update.
OCNSSF Ingress Gateway Microservice
This microservice is an entry point for accessing OCNSSF supported service operations and provides the functionality of OAuth validator.
OCNSSF Egress Gateway Microservice
This microservice is responsible to route OCNSSF initiated egress messages to other NFs.