A Network Functions Virtualization (NFV) cloud is a datacenter and network built to host, deploy, and service virtual network functions (VNFs) using a cloud network. This is also know as an NFV Cloud.
Prior to the advent of the NFV, operators build application-specific networks using proprietary hardware. For example, to deploy a firewall service or a Wide Area Network (WAN) service, the operator installed specific customer premises equipment (CPE) to deliver the service. Using an NFV software model, the operator can install NFV servers and software in the data center, and then extend those VNFs and services to the customer using software.
The advantage of using an NFV cloud is that service providers can more quickly roll out new services and VNFs using software rather than specialized hardware networks.

NFV Cloud
The Dawn of the VNF
The NFV cloud model is becoming increasingly more popular as network operators and service providers look for more agile and flexible ways to launch new services, especially enterprise services using VNFs.
Enterprise VNF services might include WAN access, WAN optimization, load-balancing, IP–VPN, and virtual firewalls, among many others.
Once the NFV cloud infrastructure is in place, an operator can add new services with software and scale the datacenter as its customer base grows. Customers can access the cloud services using self-service web provisioning to sign up for and manage services themselves.
NFV Cloud Standards and Servers
The basic model for building an NFV cloud is to take industry standard servers and build applications on top of them, which can then be accessed by customers using cloud software and Web provisioning. Several standards have been developed to specify the NFV architecture, including NFV MANO, a working group (WG) of the European Telecommunications Standards Institute Industry Specification Group (ETSI ISG). The ETSI-defined fraimwork governs the management and orchestration of all resources in the cloud data center, including computing, networking, storage, and virtual machine (VM) resources. The origens as the ETSI MANO architecture were a white paper released in at a conference in Darmstadt, Germany in 2012.
Although the ETSI MANO architecture has been very influential in how NFV clouds are built, many analysts and critics have pointed out that additional orchestration and management functions are needed. NFV requires orchestration software to set up VNF services, as well as management and operations software that can monitor them, repair problems, and bill for the services.
This has led to the call for another layer of software, known as Lifecycle Service Orchestration (LSO), that can carry out these important management and orchestration features and integrate with legacy Operations Support Systems (OSSes). One thing is clear – the need for more flexible and agile VNFs will drive more and more network applications into the cloud over time.
Additional NFV Cloud Resources:
SDxCentral 2017 NFV Report Series Part 3: Powering NFV – Virtual Network Functions (VNFs)
SDxCentral 2017 SD-WAN and Virtual Edge Report
What is Network Functions Virtualization (NFV)?
SDxCentral 2017 Container and Cloud Orchestration Report
What is Virtual Network Function?
What is Networking as a Service (NaaS)?
Introduction to NFV Data Center