Motivated by the internets of the future, which will likely be considerably larger in size as well as highly heterogeneous and decentralized, we propose Decentralize- SDN, a Software-Defined Networking (SDN) framework that enables both physical- as well as logical distribution of the SDN control plane. D-SDN accomplishes network control distribution by defining a hierarchy of controllers that can "match" an internet's organizational and administrative structure. By delegating control between main controllers and secondary controllers, DSDN is able to accommodate administrative decentralization and autonomy, as well as possible disruptions that may be part of the operation of future internets. D-SDN specifies the protocols used for communication between main controllers as well as for main controller secondary controller- and secondary controller-secondary controller communication. Another distinguishing feature of D-SDN is that it incorporates security as an integral part of the framework and its underlying protocols. This paper describes our D-SDN framework as well as its protocols. It also presents our prototype implementation and proof-of-concept experimentation on a real testbed in which we showcase two use cases, namely network capacity sharing and public safety network services.
