 Efficiency: The NFV platform should provide the tight NF SLAs on performance or availability, identical to the SLAs offered with dedicated services. For example, the SLA may specify the average delay, bandwidth, and the availability for all the services provided to one customer. To support the SLA compliance, the platform should closely monitor the performance for each customer and dynamically adapt the resources to meet the SLAs. Scalability: The platform should support a large number of VNFs and scale as the number of subscribers/applications/traffic volume grow. The ability to offer a per-customer selection of NFs could potentially lead to the creation of new offerings and hence new ways for operators to monetize their networks. Reliability: The platform should abide by NFV reliability require- ments. Service availability, as defined by NFV, refers to the end-to-end service availability that includes all the elements in the end-to-end service (VNFs and infrastructure components). Elasticity: Building on top of the virtualization technology, an NFV platform should be able to leverage the benefit of running instances in the cloud: multiplexing and dynamical scaling. For multiplexing, it allows the same NF instance to serve multiple end users in order to maximize the resource utilization of the NF. On the other hand, for dynamical scaling, when the demand changes, the network operators should be able to dynamically increase/decrease the number and/or 3 Network Function Virtualization size of each NF type to accommodate the changing demands. This, in turn, will allow the telecom service providers to offer their customers with the "pay as you grow" business models and avoid provisioning for peak traffic. It should support subscriber-based, application-based, device-based, and operator-specific policies simultaneously. More- over, adding or removing new NFs should be easily manageable by the network operator, without requiring the physical presence of technicians on the site or having the enterprise customers invol