SDN is a new networking paradigm, which separates the control plane and data plane, for the implementation of flexible networking. The SDN controller is a logic centralized management entity that it collects the global network information from the switches and then dynamically adjusts the setting of the switches for the optimization of the network performance. Therefore, the network management tasks are simplified and new protocols can be deployed faster. In this book, we survey many kinds of multipath routing protocols and multipath TCP mechanisms in SDN. Finally, we will give some concluding remarks and future research directions.