1. Policy and Charging Application User Guide
  2. Policy DRA Overview
  3. The Policy DRA Function

The Policy DRA Function

Policy DRA offers a scalable, geo-diverse Diameter function that creates a binding between a subscriber and a Policy and Charging Rules Function (PCRF) and routes all policy messages for a given subscriber and APN to the PCRF that currently hosts that subscriber’s policy rules. Additionally, Policy DRA can perform Topology Hiding to hide the PCRF from specified Clients.

Policy DRA provides various capabilities:
  • Support for all DSR application IDIH requirements; Policy DRA captures metadata that can be used with IDIH to create traces (this assumes that the desired traces are configured in IDIH)
  • Distribution of new Gx and Gxx binding capable sessions across available PCRFs

    Note:

    Gx-Prime uses the same Application-Id and Vendor-Id as Gx.
  • Routing of binding capable and binding independent (e.g. Rx, Gx-Prime) policy signaling to the correct PCRF for subscribers with an existing binding
  • Binding of subscriber keys such as IMSI, MSISDN, and IP addresses to a selected PCRF when the initial Gx, Gxx, or S9 sessions are already established to that PCRF
  • Network-wide correlation of subscriber sessions such that all Policy sessions for a given subscriber are routed to the same PCRF
  • Creation of multiple pools of PCRFs, which are selected using the combination of IMSI and Access Point Name (APN). This capability allows you to route policy Diameter signaling initiating from a given APN to a designated subset of the PCRFs that can provide specialized policy treatment using knowledge of the APN.

    Note:

    APNs must be configured before enabling the PCRF Pooling feature.
  • Use of multiple binding keys that identify a subscriber, so that sessions with these binding keys can still be routed to the PCRF assigned to the subscriber
  • Efficient routing of Diameter messages such that any Client in the network can signal to any PCRF in the network, and vice-versa, without requiring full-mesh Diameter connectivity
  • Hiding of PCRF topology information from specified Clients
  • The ability to divert a controlled amount of policy signaling to a small subset of the PCRFs in a PCRF Pool for purposes of testing new PCRF capabilities.

Use the Policy DRA GUI to perform configuration and maintenance tasks, edit System Options, and view elements for the Policy DRA Configuration and Maintenance components.

The Session Binding Repository (SBR) hosts the Session and Binding databases, which provide a distributed scalable and High Available (HA) database function to the Policy DRA function for storing and managing the Session data and the subscriber-PCRF Binding data.