Hybrid networks are heterogeneous networks merging both wireless and ad hoc nodes and where the interconnection to the IP world is an important topic through gateways called AP (access point). Indeed, each node can be contacted and can contact another node in the Internet. To reach that, architectures that support mobility management are studied. The solutions inspired by wired networks are not particularly suited to hybrid networks. We propose to use a virtual dynamic infrastructure including both backbone and clusters. A backbone is suited to spare energy, optimize control traffic diffusion and hierarchize participants. The clusters are intended to create service areas and to handle particularly the mobility management. We present algorithms to both construct and maintain such structure. This dynamic topology is robust according to mobility, and is well suited to implement mobility management and localization procedure. Finally, the number of backbone members and clusters are completely parameterizable according to the environment.