Network Integration

Here we provide an overview of the main interfaces to the Tango Policy and Charging Control (PCC) platform. This section contains the following sections:

Overview

The Tango Policy and Charging Control (iAX PCC) is deployed outside the packet data network to apply policy and charging control to data traffic. The Policy and Charging Enforcement Function (PCEF) resides in the PDN network and carries out the following tasks for data traffic:

  • Meter the duration and volume of data usage

  • Perform deep packet inspection

  • Perform real-time charging and control

The Tango iAX PCC may be deployed in GPRS/3G, CDMA, WiMAX or other IP networks.

Network Context

iAX PCC Interfaces

The Tango iAX PCC system is made up by the following functional blocks:

  • Policy and Charging Rules Function (PCRF)

  • Subscriber Policy and Charging Manager (SPCM)

Other important network components include:

  • Policy and Charging Enforcement Function (PCEF)

  • Application Function (AF)

  • Online/Offline Charging System (OCS)

  • Subscription Profile Repository (SPR)

The following sections describe the interfaces between the main functional blocks.

Rx Interface

The Rx interface resides between the Application Function (AF) and the PCRF.

The AF may be a third party application server.

This interface enables the transport of application level session information from the AF to the PCRF. Such information includes, but is not limited to, the following:

  • IP filter information to identify the service data flow for policy control and/or differentiated charging

  • Media/application bandwidth requirements for QoS control

The Rx interface enables the AF to subscribe to notifications on the IP-CAN bearer level events (e.g. signalling path status of AF session) in the IP-CAN.

Gx Interface

The Gx interface resides between the PCRF and PCEF and allows for the provisioning and removal of PCC rules from the PCRF to the PCEF and the transmission of traffic events from the PCEF to the PCRF. The Gx interface supports the following functions:

  • Request for PCC decision from PCEF to PCRF

  • Provision of PCC decision from PCRF to PCEF

  • Negotiation of IP-CAN bearer establishment mode (UE-only or UE/NW)

  • Gx usage monitoring

  • Push rules to the PCEF based on Sp notifications

  • PCRF rules update based on event reports from the PCEF (location-change, revalidation-time-expired, etc.)

  • Termination of Gx session (corresponding to an IP-CAN session) by PCEF or PCRF

The PCRF decision to terminate a Gx session is based on operator policies. It should only occur in rare situations (e.g. the removal of a UE subscription) to avoid service interruption due to the termination of the IP-CAN session.

Sp Interface

The Sp interface lies between the Tango SPCM or third-party SPR and the PCRF.

The Sp interface allows the PCRF to request subscription information related to the IP-CAN transport level policies from the SPCM or SPR based on the Subscriber ID (MSISDN or IMSI).

The interface allows the SPCM or SPR to notify the PCRF when the subscription information has been changed if the PCRF has requested such notifications. The SPCM or SPR shall stop sending the updated subscription information when a cancellation notification request has been received from the PCRF.