ew use cases for NFV in [10]. In total, there are nine use cases. We introduce the high-level description of each use case as follows. More discussions related to telecom and 5G use cases are covered in later sections. 1) NFV Infrastructure as a Service (IaaS): Due to the geographic distribution needs and cost reduction benefits, there is a need for operators to run their network functions on the infrastructure that belong to service providers. For example, instead of deploying its own infrastructure in Europe, a US carrier can choose to deploy its VNFs on a European network service provider's NFVI. In this model, the latter is offering its NFVI as a service. 3.2 NFV Use Cases and Examples 2) Virtual network function as a service: Purchasing and maintaining their own dedicated network service appliances may be too expen- sive for some small enterprises. Today, the enterprises usually have to buy a multifunction access gateway, which is hard to upgrade or maintain. NFV allows them to purchase functions whenever and wherever needed as a pay-as-you-use model. 3) Virtual network Platform as a Service (PaaS): Service provider today already provides various virtual private network services to their customers. Enterprises need to deploy virtual network to connect their remote offices and employees in a seamless manner. With NFV, the virtual network platform includes not only the routing and switching gear but also various network functions, which can provide additional security and QoS to the enterprise network. 4) VNF forwarding graphs: A VNF forwarding graph refers to a pipeline of VNFs that traffic should traverse through. It is also known as SFC. The pipeline can provide a flexible and config- urable set of services to a given traffic aggregate. With the VFN forwarding graph, the customer can choose any combination of the services according to the policies from tenants, applications, and networks. 5) Virtualization of mobile core network and IMS: Mobile core network needs resource elasticity to accommodate unforesee