Distributed Ledger-Based Approach for Secure and Efficient Integration of SDN and DTN

Abstract

In post-deployment environments with sparse or intermittent communication infrastructure, Delay Tolerant Networks (DTNs) play a critical role in maintaining connectivity through a store-carry-and-forward mechanism. To improve control and adaptability in such networks, the integration of Software-Defined Networking (SDN) is being actively investigated due to its centralized programmability and dynamic network management capabilities. Despite their individual strengths, integrating SDNs with DTNs is fundamentally challenging because intermittent controller-switch reachability prevents the controller from maintaining a sufficiently fresh and consistent network view. This limitation is further aggravated by selfish or untrusted nodes, which reduce forwarding cooperation and undermine the reliability of participation and control-related updates. As a result, SDN-DTN integration requires not only control-view continuity under disruption, but also trustworthy participation and control-plane regulation. To address these challenges, we propose a hybrid SDN-DTN framework that combines Zero-sum and Fluctuation-value Time tokens (ZFT) with a DAG-based distributed ledger. The ledger maintains the freshest controller-reachable versioned state under intermittent connectivity, while ZFT-backed validation restricts participation and control influence to contributing and verifiable nodes. In this way, the proposed framework jointly supports control-view continuity, trustworthy participation, and secure control-plane operation in challenged DTN environments. Simulations conducted with the ONE simulator show substantial improvements in network efficiency, stability, and fairness, even under high levels of selfish node participation. This framework effectively bridges the technical and conceptual divide between DTN and SDN, enabling their complementary integration and mitigating the limitations of each to achieve robust interoperability.