BlockSDN-VC: A SDN-Based Virtual Coordinate-Enhanced Transaction Broadcast Framework for High-Performance Blockchains

TL;DR

This paper proposes BlockSDN-VC, an SDN-based framework that centralizes virtual-coordinate computation and relay control to accelerate transaction broadcast in blockchains. By solving a convex optimization for a globally consistent VCS and employing a latency-aware early-outburst relay policy with a small set of random cross-cluster bridges, it achieves significant latency reductions and faster convergence while maintaining low control-plane overhead. The approach is resilient to Byzantine behavior through controller safeguards and a last-known-good fallback, and it delivers practical gains in both simulations (up to 62% latency reduction and 4× faster convergence) and a live Conflux deployment (17% higher confirmed throughput) without modifying existing clients. The work demonstrates that incremental deployment of a centralized, telemetry-informed propagation plane can meaningfully improve performance in modern, high-throughput blockchains while preserving decentralised trust assumptions.

Abstract

Modern blockchains need fast, reliable propagation to balance security and throughput. Virtual-coordinate methods speed dissemination but rely on slow iterative updates, leaving nodes out of sync. We present BlockSDN-VC, a transaction-broadcast protocol that centralises coordinate computation and forwarding control in an SDN controller, delivering global consistency, minimal path stretch and rapid response to churn or congestion. In geo-distributed simulations, BlockSDN-VC cuts median latency by up to 62% and accelerates convergence fourfold over state-of-the-art schemes with under 3% control-plane overhead. In a real blockchain environment, BlockSDN-VC boosts confirmed-transaction throughput by 17% under adversarial workloads, requiring no modifications to existing clients.

Figures (7)

• Figure 1: Parameter exploration for BlockSDN-VC.
• Figure 2: End-to-end propagation-latency CDFs under normal conditions ($n\!=\!1\,000$). At equal bandwidth BlockSDN-VC halves the median latency of the best prior scheme (Mercury) and is $2$–$3\times$ faster than Random and BlockP2P.
• Figure 3: Propagation-latency CDFs for BlockSDN-VC under RTT-forgery attacks. Even with 49 % Byzantine peers the slowdown stays below 32 %.
• Figure 4: Coordinate-forgery attack: comparison of propagation schemes. BlockSDN-VC remains the fastest even with 49 % adversaries, while Mercury slows by 97 %.
• Figure 5: Worst-case VCS subversion.