Orchestrator is a term frequently used when referring to software defined networking (SDN) and network functions virtualization (NFV) solutions. However, there is lack of clarity about the different types of orchestrators―their domains, roles, and responsibilities. This paper provides an overview of a scalable hierarchy of orchestrators to support an evolving multi-vendor SDN and NFV network―in addition to describing a high-level information flow among them. The paper also provides Nokia’s recommended approach for successful deployment.