The Global Environment for Network Innovations (GENI) is a community-driven research and development effort to build a collaborative and exploratory network experimentation platform, a "virtual laboratory" for the design, implementation and evaluation of future Internets. In this paper, we present an overview of PrimoGENI, a GENI project with the goal of extending the GENI suite of interoperable infrastructure to allow network experiments at scale, involving physical, simulated and emulated network entities.