A Blockchain-Decoupled QoS Framework for Secure and Low-Latency Tactile Internet over SDN

Abstract

Network security and Quality of Service (QoS) assurance pose dual challenges that conventional Software-Defined Networking (SDN) architectures address only in isolation. This paper proposes a unified SDN-Blockchain-Tactile Internet framework. It introduces the Blockchain Decoupled QOS Scheduling Algorithm (BQSA). This formal scheduling mechanism enforces latency-class-aware traffic prioritization while decoupling Hyperledger Fabric consensus operations from the data plane forwarding critical path. The proposed architecture integrates a Ryu SDN controller with a permissioned Hyperledger Fabric Blockchain operating under Raft consensus, augmented by Tactile Internet-inspired traffic classification and fast path forwarding for delay-sensitive flows. BQSA is formally specified using pseudocode, with an O(n log n) complexity analysis, and a control plane latency-bound theorem that guarantees Blockchain validation overhead does not propagate to Tactile flow forwarding delay. Experimental evaluation in a Mininet 2.3.0 emulation environment with Hyperledger Fabric v2.5.14 demonstrates that the proposed framework (C3) achieves a latency of 16.0 ms, jitter of 2.8 ms, throughput of 96.0 Mbps, and packet loss of 1.0%, outperforming both traditional SDN (C1) and SDN-Blockchain (C2) baselines across all four QoS dimensions and comparing favorably with representative values reported in prior SDN Blockchain literature. Blockchain-based flow rule integrity validation achieves a 96-97.5% detection rate for unauthorized rule modification with an average response time of 11-13 ms. These results establish that architectural decoupling of Blockchain validation from forwarding-critical operations is a viable and effective strategy for building networks that are simultaneously secure, auditable, and QoS-responsive.