A Handover Mechanism for Centralized/Decentralized Networks over Disruptive Scenarios

In this paper, we propose a handover mechanism to mitigate connectivity problems in centralized networks by introducing a mechanism that enables proactive switching between centralized and decentralized control. We start with the hypothesis that Software-Defined Networking (SDN) can improve the management of Tactical Networks (TNs) by introducing controllers that logically centralize the enforcement of network policies. Thus, a deployed command post can manage the IP data flows among mobile nodes, if connectivity is available. However, connectivity failures between the SDN controller and the mobile nodes at the edge of the network will interrupt the data flow(s) and the topology control by the centralized controller. Therefore, we introduce a handover mechanism deployed on the mobile nodes to switch the communication mode from centralized to distributed control when the SDN infrastructure is unavailable, and vice-versa. Our hypothesis is verified by experiments, in an emulated network with constrained links, showing that establishing a decentralized connection can mitigate the disruption of data flows also reducing packet loss. The quantitative analysis suggests that our mechanism was able to reduce about 70% of packet loss and increase the network connectivity by about 65% in disruptive scenarios.