The invention relates to a method of notifying an Application Function, AF, in a communications network of resource restrictions relating to a communications session. The network includes a Policy and Charging Rules Function, PCRF, for authorising and controlling flows of data in the session. In the method the AF sends an authorisation request to the PCRF for establishing the communication session. The authorisation request includes an indication that the AF is to be notified of resource restrictions for the data flows in the session. The PCRF notifies the AF of the resource restrictions.