One of the most challenging issues facing designers of wireless and mobile networks is the proper provisioning of Quality of Service (QoS), and is probably the most difficult problem in terms of meeting users’ QoS requirement at various mobility levels. In this paper, we propose a seamless QoS handling mechanism for diverse mobility situations. This architecture consists of a Differentiated Service (DiffServ) model and an Integrated Service (IntServ) model. We propose the class upgrade scheme in packet forwarding for smooth QoS handling of macro mobility and propose a multiple path reservation scheme based on the Resource Reservation Protocol (RSVP) for seamless QoS handling of micro mobility. The proposed mechanism can meet constant QoS requirements after mobility. Furthermore, it is so flexible and scalable that it can be utilized as the QoS model in the next wireless and mobile networks.