Within ad hoc networks, applications in general, and more specifically those with real-time constraints need to react to rapid variations in network resource availability. Hence, in order to operate correctly at application level, an accurate view on available network resources along computed paths is required.In this paper, we present a new mechanism that notifies instantly to the applications about changes occurring on network paths and their QoS characteristics. Our approach is based on an extension of a proactive ad hoc routing protocol that sends detected changes to a configurable "event channel". Then, this channel forwards them selectively to applications using filtering rules.Performed tests show that our mechanism has low impact on the performance of the routing protocol and a real improvement on applications behaviour.