dapted for the virtualized environment. NFV is tightly related to various new technologies, including the network virtualization, SDN, and cloud computing. In the next 5 years, NFV will continue to grow and will have a wide deployment in telecom networks. For example, AT&T has announced Domain 2.0 project, which will fundamentally transform their infrastructure using NFV and SDN technologies in the next 5 years. NFV will also have broad applicability in large enterprise networks to reduce their CAPEX and OPEX. We discuss four key technologies of cloud com- puting that are used in NFVI. The first one is on-demand, self-service, meaning that the operators can easily allocate resources such as server time, storage, and network. The second feature is a flexible and board network access, meaning that any VNF can route traffic to another VNF freely if needed. The third feature is resource pooling. Within a single NFVI point of presence (PoP), one type of VNF may need to deploy on multiple instances. To support dynamically changing resource allocation, VNFs can be deployed on a pool of available resources. The last feature is rapid elasticity for the sake of load surge, failover, and power optimization. 3 Network Function Virtualization OSS/BSS Os-Ma management and Se-Ma orchestration Service, VNF, infrastructure description Orchestration Or-Vnfm Ve-Vnfm VNF manager Or-Vi Virtual Virtual Virtual Vi-Vnfm compute storage network VN-NF Virtualization layer Nf-Vi Virtualized infrastructure Compute Storage Network manager Physical resources Figure 3.3 OPNFV architecture. The open-source community OPNFV has been growing and push- ing the open-source development of the NFV infrastructure. One open-source NFV activity is called OPNFV [13]. Figure 3.3 shows the OPNFV architecture. It provides the best carrier-grade NFVI, virtualized infrastructure management (VIM), and APIs to other NFV elements. It forms the basic infrastructure required for VNFs and MANO components. NFV Use Cases and Examples ETSI working group has defined a f