This paper describes the design and performance of a novel medium access control (MAC) protocol, called reservation CSMA/CA for QoS (quality of service) support over mobile ad-hoc networks. The reservation CSMA/CA protocol is based on an hierarchical approach consisting of two sublayers. The lower sublayer of the MAC protocol provides a fundamental access method using CSMA/CA to support asynchronous data traffic over mobile ad-hoc networks. The upper sublayer is designed to support real-time periodic traffic with QoS requirements by making a slot reservation with the three-way handshake prior to actual data transmission. The proposed protocol has been validated using the ns network simulator with wireless and mobility extensions. The simulation results show that the reservation CSMA/CA offers the higher throughput with the higher load for real-time periodic traffic compared to the IEEE 802.11 standard, while providing deterministic delay performance.