ts per second capacity. The cus- tomers' perceived performance should meet the predefined service level agreement (SLA). In SDN, how to deal with the response time of the controller considering the need to configure flows and how to provide sufficient bandwidth using a combination of gears are important questions to be answered. In NFV, how to control and reduce the additional overhead introduced by traversing several NFs and how to hide the overhead of virtualization techniques are critical to meeting the performance requirement. Openness: One of the key questions to enable openness is at what level of abstraction should be defined for different interfaces. The trade-offs between modularity and extensibility need to be care- fully examined. For example, how one can add additional features to interfaces without affecting other parts of the system. Internetworking and interoperability: On the one hand, the network will gradually change. Seamlessly interconnecting SDN/NFV net- works with traditional legacy networks is critical to its deployment. The devices supporting the new technologies should be able to com- municate with legacy devices using traditional protocols, and the performance should not be compromised in this process. 1 Introduction Sustainability: Energy efficiency has drawn significant attentions in the carrier network recently, both for the sake of reducing cost and for meeting the governance regulation requirements. The ability to switch off functionality and hardware, which is currently not in use, and how to make most efficient use of available processing capabil- ities are the key enablers to an energy-efficient network. Resiliency: In evaluating a network design, the network resilience is an important factor, as a failure of a few milliseconds may eas- ily result in terabyte data losses on high-speed links. In traditional networks, where both control and data packets are transmitted on the same link, the control and data information are equally affected when a failure happens. In the SDN and NFV