The PCRF (policy rules and billing function) and PCEF (policy enforcement and billing function) are two closely related functional entities, which include policy control decision making and billing control functionality. based on the flow. PCRF is designed to provide network control relating to service data flow detection, quality of service and charge-based charging control at PCEF, while the PCEF protocol essentially manages user traffic and the quality of service at the gateway. In addition, it is also responsible for detecting service data flows, metering as well as online and offline charging interactions.

What is the PCRF ??

PCRF (policy rules and billing function) is a dedicated policy functional entity standardized in the 3GPP protocol. It provides the policy functions necessary for bandwidth and charging on multimedia networks. This was introduced in September 2007 along with the standards for the 3GPP architecture. The PCRF function is part of the PCC architecture, which also includes the rules enforcement and charging function (PCEF) and the session control by proxy call function (P-CSCF).

Generally, PCRF gathers information inside the hosting network. therefore, it can be seen as part of the overall network architecture. PCRF makes intelligent policy decisions for each active subscriber on the network automatically. Almost all operational support systems (OSS) as well as other sources (such as portals) in real time support the creation of rules which ultimately help in policy making. This is a clear sign of a network offering several services, charging rules and quality of service (QoS) levels.

Basically, PCRF operates based on the received session and media information via the application function (AF). Then, this information is transferred to the AF area of ​​traffic planning events. The PCRF is the entity that applies the PCC rules to the PCEF using the Gateway interface. Most subscriber information databases and other specialized functions are accessible to PCRF. In addition to this, information relating to charging systems is also accessible to PCRF in a more scalable and centralized manner. Thanks to the real-time operation of PCRF, it generates an increased strategic importance and a more important potential role than many other legacy strategy engines.

What is PCEF ??

The rule enforcement and billing function, or commonly known as PCEF, is the functional entity that includes rule enforcement and the following billing functionality. This functional element is located at the gateway level and is responsible for providing controller functions in traffic management and quality of service of the gateway on the user level, as well as detecting the flow of service data, counting by including the different interactions of online and offline taxation.

In general, PCEF can select an appropriate PCC (billing policy and control) rule for the process of evaluating each packet received against the service data flow filters of the PCC rules. This will mainly be done by considering the order of priority of each CCP rule. Once a packet is matched with a service data flow filter, it is considered to be the packet matching process for that particular packet. Therefore, the CCP rule for this filter can be applied without problem.

PCEF plays a major role in examining a certain flow of service data, controlled by policy control. The service data flow is authorized to cross the gateway by the PCEF, only when the corresponding door is accessible.

What is the difference between PCRF and PCEF?

  • PCEF and PCRF are both functional entities involved at different levels of billing control implementation.
  • PCEF and PCRF use policy and billing control rules.
  • The PCRF mainly includes decision-making functions of policy control and flow-based billing control, while the PCEF is more concerned with the application of policies and with follow-up billing functions.
  • When examining predefined PCC rules, they are preconfigured by the PCEF, but the activation or deactivation of these predefined PCC rules can only be carried out by the PCRF function.
  • PCEF supports online and offline load interactions while PCRF does.