A solution for IP mobility support in software defined networks A large number of solutions have been proposed to support mobility in IP networks including original Mobile IP, its derivatives and several newly proposed protocols. However, these solutions have drawbacks in different aspects including triangle routing, handover inefficiency, heavy signaling overhead, etc. In this paper, we argue that these problems can be addressed based on Software Defined Networks (SDN). We discuss why SDN helps to solve the problems in current IP mobility protocols and give our algorithms to demonstrate how the problems are solved. We also present an Openflow-based protocol design to realize our idea. We show performance benefits of our protocol comparing with existing IP mobility protocols through implementation and experiments on Mininet.