The disclosure relates to a technique for determining for a broadcast or multicast session the availability of resources in a hierarchically organized content distribution network. The network includes on a lower hierarchy level a plurality of service area portions such as individual radio cells. In one embodiment, an availability request is sent from a network component on a higher hierarchy level towards one or more network components on a lower hierarchy level. In response to the availability request, one or more feedback messages including resource availability information relating to one or more service area portions are received.