In this work we propose a QoS architecture for MANETs based on a probe-based distributed admission control mechanism and the IEEE 802.11e technology. Our aim is to improve peer-to-peer communication in wireless mobile ad hoc networks by supporting real-time multimedia streaming. This technology can adapt to applications with bandwidth, delay and jitter constraints, and yet we keep to a minimum the requirements imposed on intermediate stations. Simulation results show that we successfully achieve our goal of supporting QoS-constrained applications in MANETs with a low overhead, confirming the adequateness of using probe-based admission control in these environments.