5G services and 4K will stress even more the future access/aggregation networks, where video contents have already become the main traffic contributor. The deployment in the convergent access of local micro data-centers (DCs) nodes is one promising approach to successfully manage this challenge. These nodes will be responsible for switching enormous amounts of traffic and simultaneously performing heavy CPU tasks (such as video or radio base band processing). Only a flexible management of these nodes based on NFV, SDN and data analytics will enable to meet these tasks. In this paper, we present a consistent and complete cost model collecting main trade-offs between energy savings and CPU processing suitable to be used in such a flexible management framework.