Cross-layering is an innovative concept in ad hoc networks for efficient multimedia transmissions in terms of providing better QoS (Quality of Service) support over a capacity-limited wireless channel. Many cross-layer proposals are already developed. They diverge in the way the sharing cross-layer concept is implemented and the type of performance gain they recommend. We propose a new cross-layer architecture, called XLEngine, for protocol QoS extensions in ad hoc networks. XLEngine is characterized by its generic nature and by its ability to support network-wide optimizations. This means that every node can have an overview of the network-wide state. To achieve this network-wide view, we propose the Local View Management Scheme (LVMS).