Method carried out by a policy decision function in a telecommunication network, the method comprising: a providing procedure for providing, to at least one of a policy enforcement function and a traffic detection function, an instruction identifying at least one service instance of a service, the at least one service instance of the service being identified in the instruction by the order according to which the at least one service instance of the service has been, have been, or may be started; and indicating at least one of: (i) a reporting rule, hereinafter referred to as "service instance level reporting rule", according to which the at least one of a policy enforcement function and a traffic detection function should report, or should not report, information to the policy decision function after occurrence of an event relating to any one of the identified at least one service instance; and (ii) an enforcement rule, hereinafter referred to as "service instance level enforcement rule", that the at least one of a policy enforcement function and a traffic detection function should enforce on a received packet relating to any one of the identified at least one service instance. a providing procedure for providing, to at least one of a policy enforcement function and a traffic detection function, an instruction identifying at least one service instance of a service, the at least one service instance of the service being identified in the instruction by the order according to which the at least one service instance of the service has been, have been, or may be started; and indicating at least one of: (i) a reporting rule, hereinafter referred to as "service instance level reporting rule", according to which the at least one of a policy enforcement function and a traffic detection function should report, or should not report, information to the policy decision function after occurrence of an event relating to any one of the identified at least one service instance; and (ii) an enforcement rule, hereinafter referred to as "service instance level enforcement rule", that the at least one of a policy enforcement function and a traffic detection function should enforce on a received packet relating to any one of the identified at least one service instance. identifying at least one service instance of a service, the at least one service instance of the service being identified in the instruction by the order according to which the at least one service instance of the service has been, have been, or may be started; and indicating at least one of: (i) a reporting rule, hereinafter referred to as "service instance level reporting rule", according to which the at least one of a policy enforcement function and a traffic detection function should report, or should not report, information to the policy decision function after occurrence of an event relating to any one of the identified at least one service instance; and (ii) an enforcement rule, hereinafter referred to as "service instance level enforcement rule", that the at least one of a policy enforcement function and a traffic detection function should enforce on a received packet relating to any one of the identified at least one service instance. (i) a reporting rule, hereinafter referred to as "service instance level reporting rule", according to which the at least one of a policy enforcement function and a traffic detection function should report, or should not report, information to the policy decision function after occurrence of an event relating to any one of the identified at least one service instance; and (ii) an enforcement rule, hereinafter referred to as "service instance level enforcement rule", that the at least one of a policy enforcement function and a traffic detection function should enforce on a received packet relating to any one of the identified at least one service instance.