A request is received to install control rules before having received a corresponding QoS Authorization, especially where the QoS Authorization requires a prior reservation of resources. The request for a bearer resource is pre-authorized before having received a QoS authorization for said request, by receiving a request for a bearer resource; determining that a QoS authorization has, not been received yet; pre-authorizing said request for the bearer resource by installing initial control rules; and updating the previously installed initial control rules with final control rules upon receipt of the QoS authorization. This pre-authorization and the submission of initial control rules are carried out from a PCRF server towards a PCEF device, before having received the QoS authorization. In particular, the pre-authorization may be triggered from a P-CSCF at the originating or destination side, or at both.