With initial funding from the National Science Foundation and with its global research partners, the StarLight consortium designed, developed, implemented, and is now operating an International Software Defined Exchange (iSDX) at the StarLight International/National Communications Exchange Facility, an open exchange facility that integrates multiple services, the majority specifically designed for large scale global data intensive science. The StarLight SDX is based on a flexible, scalable, programmable platform. The SDX initiative is comprised of a) providing production services, b) a series of experimental research projects, c) an experimental research testbed and d) and means of integrating multiple experimental research testbeds. Services incorporate those based on 100 and 400 Gbps Data Transfer Nodes (DTNs) for Wide Area Networks (WANs), including trans-oceanic WANs. Currently, a key focus is scaling to 400, 800 Gbps, 1.2 Tbps, 1.6 Tbps WAN and LAN E2E technologies that provide high performance transport services for exascale science, controlled using programmable data plane techniques such as Software Defined Networking (SDN) and techniques for programming data planes, e.g., with the P4 network programming language. Another research area is providing services interoperability among R&E open exchange points world wide.