Grant numbers : Work funded by Spanish MINECO DESTELLO (TEC2015-69256-R) project.© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

A modular SDN architecture for flexi-grid networks, relying on the NFV framework, allows on-demand allocation and composition of virtualized control plane functions into instances, in a cost effective way. We demonstrate its use in the adaptive control of BVTs.