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What is Policy and Charging Control

What is Policy and Charging Control ?

To understand what exactly Policy and Charging Control (PCC) is (and where it’s going), we need to take a step back and look at the two main components of PCC, then explore the advantages to operators of integrating policy and charging into a unified PCC platform.

Quick Review of Policy

First up is a quick review of policy management (often called PCRF – policy control rules function).  Policy management enables operators to dynamically control network resources with real-time policies based on service, subscriber or usage context. Policy first came about in order to manage network traffic and was very much used to control network opex. The first use of policy was to control network access to customers who abused an operator’s fair usage rules. Policy has evolved since then and it is now being used as a marketing enabler as well as a network control tool. Now we can see policy in many of the everyday uses of mobile telecoms. For example, when a customer goes over their monthly allocation of data they are often throttled and their data traffic is reduced to a much lower speed. It is policy management that is dynamically controlling the network resource (in this case, speed) available to this mobile user.  Now we’re seeing policy used in many everyday use cases, such as enabling service tiers or enabling different Quality-of-Service (QoS) for different traffic. For example, video traffic may be allocated a higher QoS to ensure the right quality is delivered to customers. Other uses include traffic prioritization, the development of service passes (e.g. only allowing customer to use specific services, such as WhatsApp, Viber, etc.) and/or roaming passes. Policy management delivers these uses cases by enforcing business rules at the network-edge, thus enabling dynamic allocation of bandwidth, variables and access to network resources by interfacing with any inline network enforcement points. In short, policy management controls the use of the network.

Adding Charging to the Mix

Charging started off as a system to charge pre-paid customers for mobile usage. Charging is the central function to collect usage records, rate them, charge for them in real-time and decrement a customer’s monetary balance (for pre-paid customers). Charging started off as part of an IN (Intelligent Network) solution designed for pre-paid voice services. However, with operators becoming increasingly data-centric, many operators are now starting to phase out their IN charging platforms and replacing them with a centralized, real-time OCS (Online Charging System) that is designed to handle data. One major change from old voice-centric IN charging and new data-centric OCSs is the ability to manage many new and more complex data offers, develop them and enable them to get to market without an army of coders from the software provider. This is why many new charging systems often include an offer catalogue that enables operators to build their own offers (e.g. with start end times, components and rate plans).

With data, and in particular LTE traffic, charging systems are now providing real-time monetization for all customers (pre and post-paid), with data transactions being collected and rated in real-time to enable operators to take any required action. These could include sending a message to the customer to let them know of their usage so as to avert bill shock, sending a trigger to upsell a specific campaign and so on. With post-paid customers, the real-time rated data record is then sent to the existing billing system for inclusion in the monthly invoice.

Charging provides the tool for operators to make money from the offers/ products enabled by policy management. Integrating charging and policy to provide PCC is logical as policy is now a central function of most mobile data offers and services. Having the ability to configure the policy and charging rules in an integrated system ensures less duplication of effort and gives operators a competitive edge as it enables a wider and richer range of products and services to get to market in a quicker time.

Policy and Charging – Combining to Make PCC

Integrated PCC offers the ability for operators to not just control subscriber entitlement and network resources, but to charge for that control with an integrated framework of real-time policy management and charging. By running policy and charging off a common framework, operators can offer innovative, convenient and flexible ways for subscribers to buy and use their services, such as on-demand services, real-time upgrades, service passes and Advice-of-Charge alerts. Figure 1 illustrates a high level view of the integration of policy and charging via the Sy interface in an operator’s network and BSS stack:

Figure 1: High Level View of PCC Integration

Functionality and the ability to handle an ever increasing number of new use cases aside, one of the main requirements of PCC is the ability to deliver the performance, low latency and scalability required to handle thousands of transactions per second (TPS) that are required for complex policy and charging scenarios. The focus on performance is only going to increase as the volume and complexity of data transactions and rules increases in line with data growth rates.

These increased data growth rates symbolize the evolution of the mobile industry and the need for PCC. Operators are under increased competitive pressure to deploy complex products and services with a reduced time to market, and they demand business agility to support rapid service innovation.  

Data is changing the speed at which operators do business. This is reflected in the move from their batch-based BSS (Business Support System) stacks (such as billing, provisioning, fulfilment, etc.) to real-time. PCC is leading the way in this move to real-time and operators are using PCC to make real-time decisions over subscriber access to network resources based on volume (usage or time), speed, application type and/or priority. PCC enables subscriber and session-aware policy decisions that are triggered by real-time and/or pre-defined events and conditions, such as changes in subscriber profile, account plan, current network capacity and source of network traffic and, if required, apply any required charge.

PCC is a relatively young technology but it’s increasingly becoming the central foundation of the BSS stack (overtaking billing, in my opinion). The reason for this is that PCC enables network controls - which are the building blocks for many new data and data-enabled products and offers - and provides flexible and real-time ways for operators not only to collect money, but also to make money.

By Martin Morgan, Director of Marketing, Openet

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