reported specifically the installation failure reasons may be expressed with a rule failure code parameter and this parameter is included in a charging rule report parameter shown as follows the charging rule report parameter in the pia message is used for feeding back the policy installation condition in the pe fe after the rule failure code parameter is added to this parameter the installation failure reason of each specific policy failed in installation may be reported during concrete realization an error reason table may be established in the pd fe and the pe fe in advance the table includes reasons of errors that may appear with each error reason corresponding to a reason value when the installation of policies sent from the pd fe to the pe fe is failed the pe fe will report reason values of the installation failures through the pia and the pd fe may get the installation failure reason of each specific policy failed in installation by referring to the error reason table 308 the pd fe sends a resource initialization answer to inform the scf a resource release process in this embodiment is shown in fig4 and includes the following steps 401 if an event trigger occurs in the pe.