2 NEF Architecture

Oracle Communications Cloud Native Core, Network Exposure Function (NEF) is a cloud native application. The application consists of the following components running on seperate namespaces in the cloud native environment:
  • CAPIF: The service interface between NEF and the external third-party applications or internal Application Functions (AFs).

    CAPIF is a 3GPP defined secured framework to expose network service interfaces. It enables the API invokers (external applications) to discover and communicate with service APIs of the API provider (NEF). This framework manages API security, logging of events, auditing capability, multiple service exposure, policy based routing, dynamic routing of information, and so on.

  • NEF: The core component that runs the business logic of NEF. It consists of various services that interacts with the CAPIF and performs the core functionality of NEF.
The NEF architecture is grouped into different components. Each component consists of multiple microservices that perform the core functionality. The following diagram represents the NEF architecture:

Figure 2-1 NEF Architecture


NEF Architecture

Components of the NEF Architecture

NEF consists of the following components and services:
  • Kubernetes cluster hosting Docker containers and Calico networking
  • Optional CNE services to support operations of NEF
  • CAPIF services:
    • API Manager: Responsible for managing the registration and publish functionality of NEF. The API Provider Domain (APD) manager service handles all the transactions related to NEF using the package services of the CAPIF that are useful for the core functionality of NEF.
    • AF Manager: Responsible for the secured interactions between API Invokers (external applications) and API Provider (NEF). This service facilitates the following tasks:
      1. API Invoker onboarding and offboarding by establishing a communication between API Invoker and CAPIF.
      2. Security Context creation. The API invoker negotiates and obtains the information about service API security method from the AF manager service.
    • Console Data Service: Responsible for all the configuration APIs and all CAPIF configurations managed through CNC Console GUI.
    • Event Manager: Manages the subscription, unsubscription, and notification for all the events supported by CAPIF. This service facilitates AFs and other NEF services to subscribe to CAPIF specific event notifications, receive notifications about the subscribed events, and unsubscribe from the notifications.
    • External Ingress Gateway: Acts as a gateway for all the HTTP requests towards CAPIF from external applications. This service provides security and load balancing functionality to manage and control the incoming traffic.
    • External Egress Gateway: Acts as a gateway for all the HTTP requests from CAPIF to external applications. This service provides security and load balancing functionality to manage and control the outgoing traffic.
    • Network Ingress Gateway: Acts as a gateway for all the HTTP requests towards CAPIF from NEF.
    • Network Egress Gateway: Acts as a gateway for all the HTTP requests from CAPIF to NEF.
  • NEF services:
    • API Router: Responsible for validation of the OAuth token received with a service request sent from API Invoker to NEF. The API Router microservice ensures that only authenticated requests are directed to NEF.
    • Monitoring Event Service: Responsible for monitoring of specific events in 3GPP system, as requested by the AFs. It communicates with the other applications to get the specific information and reports it to the respective AF.

      The ME service performs event monitoring function that includes monitoring event configuration, monitoring event report, and network initiated notification of monitoring event cancellation.

    • Quality of Service(QoS) Service: Responsible for provisioning of QoS specifications in 3GPP system, as requested by the AFs. It communicates with the other NFs to set up data sessions with the required QoS.

      The NEF QoS service facilitates the provisioning capability to AFs for sending the quality related parameters to NEF and receive the corresponding notifications.

      The service allows AFs to set up a session with required QoS and priority handling that includes AF session subscription, AF session deletion, and QoS event notification.

    • Expiry Auditor: Detects and processes the expired subscription records for the ME service.
    • APD Manager: Responsible for monitoring the site status in a georedundant deployment using the cnDBTier REST APIs.

      This service monitors the notifications received from Netwrok Repository Function (NRF) and tracks the health of all the NEF instances in a georedundant deployment.

    • Traffic Influence: Handles all the traffic influence subscription requests, validates and manages the data associated with these requests.
    • Diameter Gateway: Acts as a gateway for all Diameter traffic to NEF Solution. The diameter interface supported here is T6x.
    • Device Trigger: The Device Trigger feature enables an Application Function (AF) to notify a particular User Equipment (UE) by sending a device trigger request through 5G core (5GC) to perform application-specific tasks such as initiating communication with AF. This is required when the AF does not hold information of IP address for the UE or if the UE is not reachable.
    • External Ingress Gateway: Acts as a gateway for all ingress traffic originating from the AFs towards NEF.
    • External Egress Gateway: Acts as a gateway for all egress traffic originating from NEF solution to AFs.
    • 5GC Ingress Gateway: Acts as a gateway for all ingress traffic originating from the 5G network functions towards NEF.
    • 5GC Egress Gateway: Acts as a gateway for all egress traffic originating from NEF solution to the 5G network functions.
    • 5GC Agent: Responsible for generating and sending the service API requests to 5G NFs. It also receives event notifications from the NFs based on the subscription created by NEF.
    • NRF Client Service: Integrates with NRF for NEF registration, discovery, and service status or load related information, along with application and performance information services. NRF discovery helps in the on-demand discovery of network functions. NRF management helps in the autonomous discovery of network functions.
    • Pool Manager: Responsible for allocating SCEF referenceId ranges for each of the features handling microservices (Monitoring Events, Device Trigger) across sites and managing membership state for each of these allocations.
    • Console Data Service: Responsible for all the configuration APIs and all NEF configurations managed through CNC Console GUI.
    • MSISDNless MO SMS: Responsible for allowing NEF to deliver the MSISDN-less MO-SMS notification message from Short Message Service - Service Center (SMSSC) to Application Function (AF).
  • Database: This is the MySQL NDB storage engine.