2 Cloud Native Core Policy Architecture

The Oracle Communications Cloud Native Core Policy is built as a cloud-native application composed of a collection of microservices running in a cloud-native environment. It separates processing/business logic and state concerns following the corresponding logical grouping of microservices/components:

• Connectivity: Components interfacing with external entities. This is where an API gateway is utilized to interface with external traffic to the PCF. These are stateless sets of components.
• Business logic: Application layer running the PCRF/PCF business logic, policy engine and various services that can be enabled based on deployment needs. These are stateless sets of components.
• Data Management: Data layer responsible for storing various types of persistent data. The PCF is built to be able to plug in different types of backend data layers that could be internal or external.

As a result, an actual policy function can be composed of the necessary micro-services to provide the desired service, For Example, PCF, PCF/PCRF, a subset of a PCF (For Example, one without usage monitoring, etc.).

Oracle Communication Cloud Native Core Policy solution takes the policy designing experience to the next level by providing ultimate flexibility, extensibility, modularization to rapidly and securely deploy new policies supporting different and existing use cases. The Converged policy solution supports both 4G and 5G networks, thereby helping operators to manage their heterogeneous network in an intuitive and consistent manner while enabling seamless interworking and migration between 4G and 5G. Below is the Cloud Native Core Policy architecture diagram:

Components of the CNC Policy Architecture:

• Kubernetes cluster hosting Docker containers and Calico networking
• Standard CNE services to support operation of the PCF
• Cloud Native Core Policy Application Services
  • API GW (HTTP/2) – API Gateway service offers single entry to all HTTP/2 traffic to access policy services. The API gateway also plays a crucial role in traffic distribution, overload control and related ingress/egress services.
  • Diameter Gateway/Connector – Enables the policy solution functions as a diameter server and offers integration over Gx, Rx, Sh, Sy and other legacy diameter services. Diameter server is also implements routing, load balancing and overload control services. Diameter Gateway acts as a gateway for all diameter traffic to Policy Solution. It also performs Round Robin load balancing across its backend peers (diameter connector and PCRF-Core).
  • Ingress Gateway acts as a Gateway for all ingress HTTP traffic to Policy Solution.
  • Egress Gateway acts as a gateway for all egress traffic originating from Policy Solution to outside the network.
  • LDAP Gateway acts as a gateway for all egress LDAP traffic towards Directory Services.
  • Diameter Connector accepts diameter messages from Diameter Gateway and converts the message to HTTP message format and sends to PCF components.
  • Soap Connector accepts the SOAP messages from ingress gateway, converts to JSON format and forwards the message to Policy DS for processing.
  • NRF Client Service, along with application info and performance info services, integrates with external NRF for service registration, discovery, and service status/ load related information. NRF discovery helps in on-demand discovery of network functions. NRF management helps in autonomous discovery of network functions.
• Cloud Native Core Policy Business Logic
  • SM Service (includes PA Service) - Provides the SMF session and application/flow based policies. The policy authorization service (Rx like interface in SBA) authorizes an AF request and creates policies as requested by the NF consumer service for the PDU session to which the AF session is bound. This service implements policy control for session management for service data flows. This service implements N7 interface to trigger session management policies towards SMF function.
  • AM Service - Implements access management service-related policies over N15 interface towards the Access and Mobility Management Function (AMF).
  • PCRF Core Service – Implements the legacy handling of PCRF core business logic, interactions with other micro-services, and triggers for policy enforcement over the Gx interface. Policy and Charging Rules Function (PCRF) is a node which functions in real-time to determine policy rules in a multimedia network.
  • Binding Service - Stores binding information related to 4G/5G subscribers and aid Diameter Gateway in forwarding AF messages.
  • UE Policy Service - Provides UE policy, including Access Network Discovery and Selection Policy (ANDSP) and UE Route Selection Policy (URSP) via the AMF transparently to the UE.Implements UE management service-related policies over N15 interface towards the AMF.
  • User Service - This service is an evolution of the 4G UDR/SPR where the PCF is able to retrieve, update, subscribe, and get notified to changes. The service implements integration with all external data sources including 5G UDR, CHF, LDAP Server, 4G Sh and Sy interfaces. SM Service, AM Service and UE service talks to PCF-User service for UDR and CHF information.
  • Policy Data Service- Interfaces 4G/5G Signalling components with protocol specific connectors to have a unified datastructure which is understandable by both 4G and 5G Components.
  • Policy Engine – Implements the policy defined business logic to perform all network policy behaviors and actions. The policies can be configured using the config management service.
  • The PRE Test Engine runs the Policy Decision Engine for test messages. Test messaged can be triggered from the config management service.
  • Configuration Management - This service provides OAM interfaces (GUI and REST) for Policy and Service provisioning. Configuration Service and CM GUI offers graphical interface for all policy-related configurations and design of policies.
  • Configuration Server - This service abstracts the database for storage and retrieval of policy configuration.
  • Query - The Query micro service processes session viewer queries triggered from configuration management service.
  • Audit - Audit micro service runs the Audit engine to detect and process stale session records.
  • App-Info - This micro service monitors application (micro-service) health and status.
  • Perf-Info - This micro service monitors application (micro-service) capacity and load status.
• Data Tier
  • Dynamic state – Store session information relevant for policy context.
  • Configuration store – Stores configuration related data