QoS research in mobile ad-hoc networks is a particularly difficult topic due to the network dynamics, variations in radio quality, limited capabilities of mobile nodes, and lack of central authority. Few studies paid attention to the QoS problems on the gateway to the ad-hoc network. This book presents the PYLON-Lite QoS model that deals with the cross-domains QoS issues. A PYLON-Lite gateway operates between the ad-hoc network, with its unique characteristics on one side, and the fixed topology access network on the other side. The fundamental differences between the two networks form the heterogeneous environment of the PYLON-Lite model. PYLON-Lite provides a, seemingly, homogeneous cross-domain QoS solution and has a flexible design that facilitates a lightweight implementation to benefit from the already existing QoS models on each side of the gateway.