Policy and Charging Enforcement Function (PCEF) was first introduced in 2007 as part of the Policy Charging Control Architecture. The elements of the PCC are designed to provide access, QoS or quality of service, resource and control to the entire configuration of the broadband gateway including offline and online charging. PCEF is designed to enforce decisions received from the policy and charging functions and relaying back access and subscriber information to the PCRF over a secure Gx interface connecting the PCEF to the PCRF.
In online charging, the PCEF architecture is designed to interact with the internal charging function leading the internal charging function to interact with the OCS or online charging system which in turn generates credit management data for pre paid charging and generates reports for OFCS or Offline Charging System regarding resource usage.
PCEF provides policy enforcement as well as charging functionalities. Located at the network gateway, the PCEF performs the role of a traffic controller distributing appropriate bandwidth as and when required. It also provides QoS at the gateway including service data flow detection, including varied interactions between online and offline charging. PCEF has a major role to play in monitoring service data flow regulated by policy control by allowing the service data to flow through the gateway only upon accessibility of the corresponding gate.
PCEF along with PCRF enable telecom carriers to provide differentiated service offerings in order to increase revenue earnings. PCEF is key to service integrity, which is why telecom carriers ensure validation of PCEF rules before launching new service offering. The testing is done to validate both service integrity as well availability of sufficient bandwidth to deliver the new service offering upon request. Similarly the carrier needs to validate the charging rules as well as per the Service Level Agreement entered into by the customer to ensure that the charges raised are commensurate with the offering based on service conditions. Every service offering by the carrier needs a different bandwidth which is where the PCEF and PCRF elements come into the picture. Their job is to ensure that network resources are utilized efficiently with minimum wastage by making sure required bandwidth is available to each service dynamically in real time.
PCEF is designed to work across a whole range of wireless networks and even comes embedded in standardized IT servers. PCEF and PCRF elements are required to manage hundreds of thousands of transactions every second which is why their service integrity is essential to ensure they can operate efficiently even under maximum capacity utilization.
Validation of PCEF and PCRF elements is fairly simple requiring the carrier to simulate the PCEF, PCRF as well as Charging and Application Function using appropriate network tools. The simulation test results provide you with the data required tovalidate for errors as well as whether the rules are being implemented successfully and the ability of the Policy functions to perform under maximum capacity stress.