OPEN is a new approach to networking that has the potential to enable on-going network innovation in a production setting. Key aspects of OPEN include: separation of data and control planes; a uniform vendor agnostic interface between control and data planes; logically centralized control plane, realized using a network OS, that constructs and presents a logical map of the entire network to services or control applications on top; and slicing and virtualization of the underlying network. With OPEN a researcher, network administrator, or third party can introduce a new capability by writing a software program that simply manipulates the logical map of a slice of the network. OPEN also forms the network substrate of NSF’s GENI infrastructure, designed to enable research at scale in networking and distributed systems. In this talk I will share the OPEN story so far: the rationale, design, deployments, and the coming together of an ecosystem.