This chapter first describes the fundamentals of edge cloud with respect to 5G networking and the associated on-going mobile network transformation. It then describes Software defined networking, its evolution from OpenFlow to P4, and network function virtualization and its implications for realizing disaggregated, control plane – user plane separated mobile core. The chapter introduces an open source platform for mobile core, namely Open Mobile Evolved Core, and discusses its evolution path. Next, it describes the disaggregation and software defined control of radio access networks, and describes the rise of white-box hardware for computation, storage, and networking, and how modern networks will take advantage of cloud technologies at the edge to meet the end devices' ever increasing demands. The chapter further provides a description of end-to-end, software defined network slicing, including programmatic slicing of the RAN and provides insights into how network slicing is related to the edge cloud.