  The European Telecommunications Standards Institute (ETSI) developed Network
Functions Virtualization (NFV) Management and Orchestration (MANO) framework.
Within that framework, NFV orchestrator (NFVO) and Virtualized Network Function
(VNF) Manager (VNFM) functional blocks are responsible for managing the
lifecycle of network services and their associated VNFs. However, they face
significant scalability and performance challenges in large-scale and
geo-distributed NFV systems. Their number and location have major implications
for the number of VNFs that can be accommodated and also for the overall system
performance. NFVO and VNFM placement is therefore a key challenge due to its
potential impact on the system scalability and performance. In this paper, we
address the placement of NFVO and VNFM in large-scale and geo-distributed NFV
infrastructure. We provide an integer linear programming formulation of the
problem and propose a two-step placement algorithm to solve it. We also conduct
a set of experiments to evaluate the proposed algorithm.
