Performance and Reliability Analysis for Practical Byzantine Fault Tolerance with Repairable Voting Nodes

TL;DR

This paper introduces a new PBFT-based blockchain system with repairable voting nodes, analyzing its performance and reliability using Markov processes, and provides algorithms and numerical validation for key system metrics.

Contribution

It develops a novel PBFT protocol with repairable nodes and offers a comprehensive performance and reliability analysis using advanced stochastic modeling techniques.

Findings

Throughput depends on node repair rates and system parameters.

The system achieves high availability with optimal repair strategies.

The approximate algorithm accurately predicts throughput under various conditions.

Abstract

The practical Byzantine fault tolerant (PBFT) consensus protocol is one of the basic consensus protocols in the development of blockchain technology. At the same time, the PBFT consensus protocol forms a basis for some other important BFT consensus protocols, such as Tendermint, Streamlet, HotStuff, and LibraBFT. In general, the voting nodes may always fail so that they can leave the PBFT-based blockchain system in a random time interval, making the number of timely available voting nodes uncertain. Thus, this uncertainty leads to the analysis of the PBFT-based blockchain systems with repairable voting nodes being more challenging. In this paper, we develop a novel PBFT consensus protocol with repairable voting nodes and study such a new blockchain system using a multi-dimensional Markov process and the first passage time method. Based on this, we provide performance and reliability analysis, including throughput, availability, and reliability, for the new PBFT-based blockchain system with repairable voting nodes. Furthermore, we provide an approximate algorithm for computing the throughput of the new PBFT-based blockchain system. We employ numerical examples to demonstrate the validity of our theoretical results and illustrate how the key system parameters influence performance measures of the PBFT-based blockchain system with repairable voting nodes. We hope the methodology and results developed in this paper will stimulate future research endeavors and open up new research trajectories in this field.