Several researches propose the identifier/locator separation architecture to address the scaling problems of today's Internet routing and addressing system. And scalable and seamless mobility support is an important task in mobile identifier/locator separation networks. In this paper, by analyzing the features, such as direct separation, flexible mapping and identifier replacement, we show that the new architecture delivers data packets more efficiently and protects location privacy better than traditional mobile IP networks, and is convenient to implement soft handover. Then we present a fast handover management scheme for the new architecture, which improves the reactive handover mode of FMIPv6 and eliminates the duplicate address detection (DAD) and return routability (RR) processes in MIPv6. The numerical results show that the scheme has good scalability and low handover latency, and has great advantages in the signaling cost and fast mobility support.