In the last few years, wireless ad hoc networks experienced a great diffusion thanks to their simple deployment everywhere and whenever needed. Already used for entertainment applications (e.g., instant messaging) or for specific domains (e.g., military) we think such technology is mature enough to support also real-time services provision.Real time applications pose several challenges, in particular issues such as limited bandwidth, unreliable channels, topology evolutions and power consumption make Quality of Service (QoS) management a mandatory task to be addressed. In this paper, we propose a general QoS systemthat makes use of Differentiated Services strategies by exploiting the concept of virtual backbones. Our key ideais to use an auto-configured virtual backbone to set up aDifferentiated Service area in order to opportunely manageQoS flows. Also, thanks to a new distributed Call Admission Control algorithm, it avoids the arise of overloading situations. Performance measurements, based on simulative techniques and carried out to test the feasibility of theproposed system, are finally presented.