PCF base configuration provides a detailed view of the configurations that are required for making PCF operational. This includes setting up the infrastructure to deploy PCF, deploying PCF through SMI, and configuring the Ops Center for exploiting the PCF capabilities over time.

This use case involves the following steps:

1. Prerequisites—Provides the list of resources that are required to deploy PCF in your environment successfully. See Prerequisites for details.

2. Deployment through SMI—All the 5G network functions are deployed through the SMI platform. The platform simplifies the cloud-native NF deployments and monitors the NF performance while providing an integrated experience.

   See Deploying PCF for details.

3. Configuring Ops Center—The PCF Ops Center provides an intuitive console for interacting with PCF in terms of configuring and gaining visibility into resources and features that you have subscribed to.

   The Ops Center lets you review the current and historical configurations corresponding to your environment. See Accessing the PCF Ops Center for details.

With moving to 5G Core, Cisco has built PCF to have a robust and flexible infrastructure. Considering the rapidly evolving industry trends in the area of capacity and bandwidth, the infrastructure is also continuously altered by converging various components to make it more reliable, scalable, and secure.

Some of the key integrations that PCF infrastructure has undergone include the Cisco Common Data Layer—PCF supports the Geographic Redundancy (GR) for the Cisco Common Data Layer (CDL). See Cisco Common Data Layer for more information.

Complying with the charging architecture published in 3GPP December 2018 release 15. In the 5G Service-based architecture, PCF interoperates with the CHF. For instance, PCF determines the policy decisions that are based on the status of the policy counters available in the CHF.

This use case involves the following steps:

• N28 Interface—PCF allows retrieval of policy counters and their use in policy decisions. See N28 Interface for details.

• Forwarding the NAP and LDAP requests—The Policy Server relies upon the NAP and LDAP server to collect the subscriber details. With the revised Policy Server, PCF processes the subscriber detail requests and sends it to the appropriate function that is PCF or PCRF. It determines the function considering the technology that the subscriber has subscribed to. See Session Queries over LDAP for details.

The Network Repository Function (NRF) is one of the key network entities in the 5G Core Network (5GC). It primarily maintains the NF profile of the available NF instances and their supported services. It permits the NF instances to subscribe to, and get notified about the registration in NRF of new NF instances. The NRF supports the service discovery function by receiving the NF Discovery Requests from NFs and providing the information of the available NF instances by satisfying specific criteria such as supporting a given service.

This use case involves the following:

• NRF Interface—The NRF offers a platform for the NFs to communicate with each other and to exchange information for carrying out their operations. However, to build this communication framework, the NFs similar to PCF must register their profiles and services with the NRF. The NFs use the NRF's native management and discovery services to establish this framework. See NRF Interface for details.

• NRF Subscription to Notifications—PCF supports NRF and the associated repository functions such as the interface discovery, registration for renaming NRF, change type, and removal or addition of new API attributes. PCF extends this support as per the 3GPP December 2018 specification compliance. See Network Repository Function Subscription to Notifications for details.

• Heartbeat—The NF heartbeat configuration enables the network functions to notify their operational status to the NRF periodically. PCF invokes a heartbeat at the configured intervals. If the NRF is unavailable, then PCF switches between the registered primary, secondary, and tertiary NRF depending on their availability. See Heartbeat for more information.

• N28 Interface—PCF discovers the NFs based on the Instance ID which the NFs provide such as CHF and UDR. See for N28 Interface and UDR Interface for details.

The policy charging solution combines with LDAP to sends and receives trusted information about the modified subscriber or subscriber details through the LDAP interface.

PCF has constructed the following capabilities to optimize the services that LDAP offers:

• PCF as an LDAP Client

  LDAP and Sh Interface—PCF acts as an LDAP client and establishes communication with Home Subscriber Server (HSS) and downloads the subscription profile over a Sh Interface. This enables PCF to update the policies automatically in the SMF when the Sh, LDAP, or local configuration sends a subscription change notification. See LDAP and Sh Interface for details.

• PCF as an LDAP Server

  Forwarding the NAP and LDAP requests—PCF acts as an LDAP server. The Policy Server relies upon NAP and the LDAP server to collect the subscriber details. With the revised Policy Server, it now processes the subscriber detail requests and sends it to the appropriate function that is PCF or PCRF. It determines the function considering the technology that the subscriber has subscribed to. See Session Queries over LDAP for details.

4G introduced cutting-edge solutions that redefined the way humans consumed cellular technology. It turned out to be an inherent part of exponential growth and amplified human advancement with AI, IoT, and other applications that exploit the technology. When 5G was conceived, some of the key capabilities of 4G were rebuilt on the 5G’s tech stack and infrastructure to provide a more scalable and positive experience to the customer base.

PCF has adopted the following feature from the 4G implementation:

Rx Authorization—PCF provides a method for service providers to regulate the services available to individual subscribers. You can configure the bearer-level regulation through the configuration of the Rx Authorization. The configuration lets you control the services available to each subscriber. See Rx Authorization for details.

In the new 5G spectrum, the subscribers are aware of the transitioning infrastructure that offers high-speed, increased capacity, reduced cost, real-time interaction, and other innovative offerings. However, the expectation that is associated with telecommunication still revolves around making regular voice calls, emergency calls, exceeding quality audio, and sending SMS. Service providers are being competitive over providing a positively differentiated experience to the user while making the Audio, Video, and Emergency calls. Like 4G, the providers can access the VoNR through PCF, which is the preferred approach.

This use case involves the following:

• VoNR through the Rx Interface—With PCF in 5G supporting full Diameter stack with the supported standard Diameter Rx interfaces, PCF accepts Rx messages for processing and Rx session binding with N7 sessions. See VoNR through the Rx Interface for details.

• Specification Compliance - N5, N7 and N28—Enhancements to the N7 and N28 interfaces of PCF to comply with the 3GPP December 2018 specification and enhancements to the N5 interface of PCF to comply with the 3GPP December 2020 specification. See Specification Compliance - N7 and N28 for details.

• Predefined Rule and Rulebase—Provision to configure PCC rule ID for predefined rule and rulebase is available in PCF. SMF uses these rules when configuring the User Plane Function (UPF) for performing data flow tasks, such as shaping, policing to provide bandwidth, and charging functions. See Predefined Rules and Rulebase for more information.

• Dynamic Rules and Table-driven Charging Rules—PCF supports the provisioning of the table-driven dynamic charging rules. See Dynamic Rules and Table-Driven Charging Rules for more information.

• Dummy N7 Notify Request—If PCF has not subscribed to specific event triggers during the session initiation, it can send a dummy N7 Notify Request, which is an intermediate request to fetch those event triggers. The events must correspond to the configured Media-Type specified in the AAR message from the IMS. See Dummy N7 Notify Request for more information.