Happy Monkey: PCRF and PCEF Integration with OpenIMS.. PCRF (Policy Control Rule Function) is one of IMS architecture which support for policy and charging control decision based on session and media related information obtained from the P-CSCF. For that implementation, i’m use UCT Policy Control Framework at my OpenIMS. So you can get the detail information of that at UCT or FOKUS project. UCT Policy Control Framework have defined two software tool for implementation, they are PCRF and PCEF (Policy and Charging Enforcement Point).