A Simulation-Based Comparison of Raft, PBFT, and PoA Consensus for Private Blockchain in Archipelagic Networks with Varying Delays Using NS3

Deploying private blockchain in archipelagic regions poses significant challenges due to network delays caused by geographic dispersion. This study evaluates the performance of three consensus mechanisms—Raft, Practical Byzantine Fault Tolerance (PBFT), and Proof of Authority (PoA)—to determine the most suitable for such environments. Using Network Simulator 3 (NS3), we simulate network scenarios with both fixed delay (5 ms) and varying delays (1 ms to 100 ms), alongside different node counts, block message sizes, transaction speeds, and transaction sizes. Key performance indicators such as consensus time and throughput are analyzed. The results show that Raft performs optimally under low-latency, stable conditions, whereas PBFT delivers the lowest consensus times but experiences performance degradation in environments with variable delays. PoA demonstrates the highest adaptability, excelling in highlatency conditions with consistent performance.It is also observed that uniform (same) delay performs better than varying delay across all consensus mechanisms, and that block message size significantly impacts performance more than transaction time. This research provides insights into selecting the optimal consensus protocol for private blockchain deployment in archipelagic infrastructures with diverse network conditions.