PCRF Server

Solution Overview

PCRF Server is a carrier-class software platform designed for creating converged policy management and real-time policy application decisions. The platform integrates into the main functional areas of the operator's network: B/OSS, core network, content applications.

PCRF Server includes 3GPP standards based implementation of PCRF (Policy and Charging Rules Function) and is an "out of box" solution for provisioning, managing and assigning policies like QoS (Quality of Service) management, bandwidth management, subscriber behavior related policies as well as policies for access to value added services in 2G/3G and LTE networks.

PCRF Server is a unified, flexible, reliable and scalable software platform for creation and management of any type of policies specific for telecommunications industry.

The PCRF Server also offers exceptional flexibility for integration with various network equipment and B/OSS systems using standard (e.g., 3GPP-specified) or non-standard interfaces/protocols.

The PCRF Server enables the rapid creation and deployment of new policies or products, enabling the operator to provide innovative and unique services/applications to subscribers.

PCRF Server consists of the following subsystems:

• PCRF Engine
• Repository
• Management subsystem
• SPR access subsystem
• Load balancers
• Studio, a graphical user interface.

The PCRF Engine is the core module that processes policy requests from network elements or B/OSS systems in real time. The main components are: Diameter-based 3GPP Gx Connector, Diameter-based 3GPP Rx Connector, Diameter-based 3GPP Sy Connector, Policy and Charging Rules Server, Policy Decision Platform, Subscriber Profile Cache and Subscription Management Service.

The repository stores all business rules, technical and configuration parameters used in the PCRF Engine, Management Subsystem, Balancers and Studio. It is a mandatory component of the PCRF Server.

The Management Subsystem is a centralized node designed to monitor and manage all PCRF Server components. It is a basic component of the PCRF Server that performs OA&M functions.

The SPR access subsystem provides APIs (Web services) to manage subscriber and subscription data in the internal SPR (Subscriber Profile Repository).

Load Balancers are a key component in the distributed deployment of the system. Load balancers provide request balancing on DIAMETER protocol level.

Studio is a Web-based user interface. It is used to create/edit policies and products. Operations and Maintenance Console (OMC) is also integrated into Studio and is designed to perform OA&M functions.

Solution Architecture

Overview of the PCRF Server architecture

PCRF Server is implemented in accordance with 3GPP standards. PCRF Server is a platform for service and charging policies creation, management and enforcement of the created policies. In this way PCRF Server executes Policy and Charging Rules Function, setting policies on PCEF depending on network type, subscriber profile, application used etc, and enabling access control, dynamic bandwidth management, quality of service (QoS) management etc.

The PCRF Server uses the data model, data processing rules and rule execution module to create and execute specific policies such as QoS control, access control, parental control, etc. according to subscriber subscriptions, requests from data network elements, etc. The PCRF Server incorporates flexible business logic with the following distinctive features: rule creation tool without the need to write any code in any programming language, a set of pre-configured rule templates, the ability to use dynamic links in the configuration.

The PCRF Server consists of four layers:

• Network Access Layer.
  • Responsible for receiving requests from the network and sending responses.
• Business logic layer.
  • Responsible for executing business logic rules
• Presentation Layer
  • User interface for developing and managing business entities and for managing and configuring various modules.
• Data storage layer
  • Responsible for storing business entities

Network access level

The PCRF Server supports the following interfaces

Gx interface.

PCRF Server supports the Gx interface specified in 3GPP TS 29.212

The PCRF Server has a flexible interface configuration mechanism and supports any specific AVPs of network equipment to implement the Customer's required scenarios.

Rx Interface

The PCRF Server supports the Rx interface specified in 3GPP TS 29.214

PCRF Server has a flexible interface configuration mechanism and supports any specific AVPs of network equipment to implement the Customer's required scenarios.

Sy Interface.

PCRF Server supports Sy interface specified in 3GPP TS 29.219

PCRF Server has a flexible mechanism for configuring interfaces and supports any specific AVPs of network equipment to implement the Customer's required scenarios.

Gy Interface.

PCRF Server supports Gy interface and acts as a DCCA-proxy between PCEF and OCS. The PCRF Server has a flexible mechanism for configuring interfaces and supports any specific AVPs of network equipment to implement the Customer's required scenarios.

Sp interface.

PCRF Server supports a Sp interface between PCRF and SPR.

This interface allows the PCRF to request information about subscriber subscriptions defining policies applicable to an IP session from the SPR by subscriber ID, PDN and IP-CAN session attributes as defined in 3GPP TS 23.203. This interface allows the SPR to notify the PCRF of changes in the subscriber profile if the PCRF has subscribed to such notifications.

Sp interface is not specified in the current 3GPP releases, so PCRF and SPR vendors can choose to implement the interface that best meets customer requirements.

Ud Interface.

The PCRF Server supports a Ud interface between the PCRF and the UDR.

This interface allows PCRF to query, create, modify and delete subscriber information stored in UDR. This interface is based on LDAP.

This interface supports subscription/notification functionality, which allows the PCRF Server to receive notifications when subscriber data in the UDR changes.

PCRF Server supports Ud interface based on LDAP protocol as defined in 3GPP TS 23.335 and TS 29.335

RADIUS interface.

PCRF Server supports integration with external AAA servers over the RADIUS protocol to receive AAA-Start and AAA-Stop messages which are forwarded to the PCRF by the AAA server when an IP-CAN session is created or closed. This mechanism allows you to correlate IP address and MSISDN subscriber.

RADIUS CoA interface PCRF Server also supports integration with network elements that do not support 3GPP standards by extending the data model and data processing rules. The PCRF Server includes a connector and processing rules to transmit service policies via a RADIUS / RADIUS CoA interface to equipment not supporting 3GPP standards. Vendor Specific Attributes can be added to the data model.

Business Logic Layer

The business logic layer includes the core functionality and major components of the PCRF Server. The most important ones are listed below:

Rules Execution Engine

The Policy Engine Subsystem makes decisions about service and charging policies based on the policy plan and input data.

PCRF Server supports the following types of plans:

• Advanced Policy Plan.
• Simple Policy Plan
• Quota Policy Plan
• Counter Policy Plan
• Calendar Policy Plan
• Decision Table Policy Plan
• Application Policy Plan
• Constrain Policy Plan
• Post-Process Policy Plan

The policy execution subsystem operates in stateless mode, handling only the data provided and does not store counter or other entity values.

A set of basic operations.

The system contains a set of basic operations used to create rules:

1. Querying data about a subscriber and his subscriptions
2. Request for counter values
3. Requesting data about a product/service
4. Policy generation (for dynamic policies)
5. Policy assignment
6. Tracking events by subscriber
7. Tracking events by session

Interface logic with external applications.

This subsystem defines the rules of interaction with external applications modifying a subscriber's IP session (performing Application Function, AF)

1. AF policy mapping. Defines mapping between AF and network access level policies Authorization of AF policies. Determines whether a policy can be executed on AF
2. AF Event Management. Sets event matching rules between AF and a network element
3. Session Management. Sets matching rules between Gx-session and Rx-session.

Presentation level

The Studio utility is used to create and modify policies in PCRF Server. This graphical user interface is used to create policy rules, check the rule structure, and save the created rules to the repository. Policies can be created using the standard templates supplied with the Solution, or the operator can create and apply his own unique policies using a flexible data model and basic operations.

Storage Layer

The PCRF Server supports integration with external SPRs as well as provides the ability to store data in an internal SPR, depending on customer requirements.

Security level

PCRF Server provides protection against unauthorized access to system elements on several levels:

Network layer

• Use of Firewall
• Secure transmission protocols:
  • SSL/HTTPS, IPSec, SNMP

Operating system level

• Secure protocol access (SSH, SFTP)
• Security add-ons

User Control Layer

• 3 differentiation levels (role level, user level, access level)
• User authentication
• User Authentication

Management level

PCRF Server provides the following functionality within OA&M:

Deployment management.

• Physical representation:
  • Physical distribution of Solution elements.
• Logical representation:
  • Display of process and data flow interactions
• Solution Node Management:
  • Adding/removing nodes (servers), querying node information (cpu, memory, disk usage, etc.)
• Process management:
  • Add/delete processes, start/stop processes, get information about processes (status, CPU usage by process, memory usage by process, etc.)
• Management of views:
  • Grouping nodes/processes into logical groups to facilitate management of hundreds of nodes/processes.

Configuration Management.

• View and modify JVM runtime parameters such as thread pool size, etc.

Performance Management

• Real-time system performance monitoring of current system utilization, load, response time, etc.
• View system performance history/statistics, build different types of graphs.

Alarm Management.

• Displaying triggered alerts
• Process triggered alerts (e.g. logging the cause of triggered alerts)
• Viewing history/statistics for alerts
• Setting thresholds for triggering alerts and criticality levels

Manage log files

• Viewing log files
• Changing logging levels

High Availability

As a critical network component, the PCRF Server provides High Availability through a distributed architecture with redundant core components. The PCRF Server solution is designed and tested to provide 99.999% availability at the software and hardware level. Internal balancing and failover mechanisms quickly track component unavailability and perform load redistribution among available Solution components.

Redundancy

PCRF Server provides several levels of redundancy to ensure a high degree of availability and performance:

• On the same server - two physical interfaces are combined into one virtual interface (IP bonding)
• At the same site - multiple servers are used to perform the same functions, primary and secondary servers are configured on the Diameter-client side (GGSN/PCEF).
• Geographic redundancy between sites. Requires twice the number of servers.
• Geographic redundancy supports Active-Standby operation to restore operation of the Solution to the Standby site in case of an emergency.

Solution elements should be connected over a 1GB network with low latency for optimal interoperability.

Scalability

The PCRF Server Solution deployment can scale from small test deployments of two (or even one) servers to very large deployments. The distributed architecture of PCRF Server provides a level of scalability that meets the requirements of the largest operators. At the same time, linear scalability is provided for the subsystems that perform transaction processing.