In the future, mobile terminals will be equipped with several interfaces to different technologies -such as UMTS, IEEE 802.11, DVB and WiMAX -and will be able to connect simultaneously to the most appropriate access networks. This paper presents a mobility and QoS architecture aiming at supporting intelligent handovers. We introduce the concept of Network-Assisted Mobile terminal Initiated HandOver (NAMIHO), where the handover decision is negotiated between the network and the user, taking into account inputs and decision algorithms running both on the terminal and network. We also present an instantiation of the architecture using IEEE 802.21 and concepts of local/global mobility. We further propose extensions to IEEE 802.21 standard.