Wireless Mesh Networking is envisioned as an economically viable paradigm and a promising technology for a wireless backbone. It should provide quality-of-service (QoS) guarantees the same as or similar to those offered by the legacy wireline backbones. A key factor in designing protocols for WMNs is to exploit its distinct characteristics such as immobility of mesh routers and less-constrained power consumption. In this paper, we propose a QoS-aware routing framework for WMNs. The framework addresses both scheduling and QoS-routing problems with cross-layer design. The framework allocates the transmit power of the WMN routers in a way that maximizes the spatial reuse of the network bandwidth. Using computer simulations, we show that, our optimal power allocation ensures the QoS satisfaction for the different traffic flows and achieves more efficient bandwidth utilization than the shortest-hop power allocation.