s, provisions, de-provisions, and manages virtual computing, storage, and networking resources while communicating with the underlying physical resources. The VIM is respon- sible for operational aspects, such as logs, metrics, alerts, root cause analysis, policy enforcement, and service assurance. It is also responsible for interacting with the orchestra- tion layer (MANO) and SDN controller. 22 Chapter 1 NFV is managed by NFV-MANO, which is an ETSI-defined framework for the manage- ment and orchestration of all resources in the cloud data center. This includes computing, networking, storage, and VM resources. The main focus of NFV-MANO is to allow flexible on-boarding and to avoid the possible disorder that can arise during transition states of net- work components. As we mentioned earlier, the NFV-MANO consists of three main components: NFVO is responsible for on-boarding of new network services and VNF packages; net- work service life cycle management; global resource management; and validation and authorization of NFVI resource requests. The NFVO is a key component of the NFV- MANO architectural framework, which helps standardize the functions of virtual net- working to increase interoperability of SDN-controlled elements. Resource management is important to ensure there are adequate compute, storage, and networking resources available to provide network services. To meet that objective, the NFVO can work either with the VIM or directly with NFVI resources, depending on the requirements. It has the ability to coordinate, authorize, release, and engage NFVI resources independent of any specific VIM. It can also control VNF instances sharing resources of the NFVI. 2. VNF manager oversees life cycle management of VNF instances; coordination and adaptation role for configuration; and event reporting between NFVI and EMs. VIM controls and manages the NFVI compute, storage, and networking resources. 1.1.2.3 Operational Aspects A VNF may be composed of one or multiple VNF components (VNFC). A VNFC may be a software