Internet Protocol (IP) mobility can be handled at different layers of the protocol stack. In this book, a Seamless IP-diversity-based Generalized Mobility Architecture (SIGMA) is described. SIGMA works at the transport layer and utilizes IP diversity to achieve seamless handover, and is designed to solve many of the drawbacks of Mobile IP. The handover performance, signaling cost, and survivability issues of SIGMA are evaluated and compared with those of Mobile IP. A hierarchical location management scheme for SIGMA is developed to reduce the signaling cost of SIGMA. In addition to terrestrial networks, SIGMA is shown to be also applicable to managing satellite handovers in space. Finally, the interoperability between SIGMA and existing Internet security mechanisms is discussed. The implementation of SIGMA in the popular network simulation platform: ns-2 is also given out in appendix. This book should be especially useful to professionals in the field of IP mobility, wireless network design, and protocol analysis.