CARMEN, CARrier grade MEsh Networks, will study and specify a wireless mesh network supporting carrier grade triple-play services for mobile/fixed network operators. Future operator networks will be comprised of a common core network and several access networks, and the CARMEN access network will complement other access technologies by providing a low cost and fast deployment mesh network access technology. The project proposes the integration of heterogeneous wireless technologies in a multi-hop fashion to provide scalable and efficient ubiquitous quad-play carrier services.To address the integration complexity of heterogeneous radio technologies, CARMEN introduces a layer 2.5 located between the subnet layer and the routing layer, in order to abstract technology specific issues into a common set of events and commands. Upper layers will use the abstract interface of layer 2.5 to dynamically adapt functions such as routing, mobility and monitoring. One relevant issue is that CARMEN will provide capacity handling algorithms to exploit specific features of the mesh networks such as the availability of multiple links between two peers (i.e. multipath) or the use of radio broadcast instead of unicast to alleviate the load of broadcast services (e.g. video) in the mesh network. CARMEN will focus on three planes: technology, message transfer, and self-configuration and management, to provide a complete solution for setting up and maintaining a cost-effective carrier grade wireless mesh access network.Soundness of the obtained results is guaranteed by the strong operator involvement, and by performing a use-case implementation. The experience of the consortium guarantees that the developed solutions will produce significant advance with respect to the current state of the art, which will be reflected in IPR creation, proposals of standards (with focus on IETF and IEEE), and dissemination of the results in high impact conferences and journals.