A method for controlling the forwarding quality in a data network comprising measuring (S11) end-to-end forwarding quality in measurement nodes (106) located outside the network core and detecting forwarding quality violations in at least one path between these nodes. According to the invention the method comprises the further steps of:—selecting (S13, S15, S17) at least one potentially overloaded interface comprised in the at least one path where quality violations were detected by combining knowledge about different end-to-end measurements performed in the network, with knowledge about the network topology and knowledge about booking levels and forwarding capacity for the interfaces;—defining (S23) a new or adjusting (S21) an already existing provisioning level for each selected interface, such that the usage of each path detected to have forwarding quality violations is limited at one or more interfaces.