More Is Not Always Better: An Analytical Study of Controller Synchronizations in Distributed SDN

Distributed software-defined networks (SDN), consisting of multiple inter-connected network domains, each managed by one SDN controller, is an emerging networking architecture that offers balanced centralized control and distributed operations. In such paradigm, most existing works focus on designing sophisticated controller-synchronization strategies to improve joint controller-decision-making for inter-domain routing. However, there still a lack fundamental understanding how the performance related attributes, thus impossible justify necessity complicated strategies. this regard, we analyse quantify enhancement architectures influenced synchronization levels, in terms resulting number abstracted routing clusters, structural properties. Based generic model incorporating link preference path constructions, establish analytical lower bounds quantifying under any arbitrarily given status. The significance these they can be used contribution controller levels improving different parameters, which therefore serves as guidance future analysis protocol designs.