The Case for Accelerating BFT Protocols Using In-Network Ordering

TL;DR

This paper introduces a new network-based ordering primitive and a BFT protocol called Matrix, significantly improving performance in data center systems by leveraging in-network ordering guarantees.

Contribution

It proposes a novel authenticated ordered multicast primitive (AOM) implemented in programmable switches and a BFT protocol that uses AOM to reduce coordination, achieving high performance.

Findings

Matrix outperforms existing BFT protocols in latency and throughput

Hardware implementations of AOM demonstrate feasibility in programmable switches

Network-assisted ordering simplifies BFT protocols and enhances efficiency

Abstract

Mission critical systems deployed in data centers today are facing more sophisticated failures. Byzantine fault tolerant (BFT) protocols are capable of masking these types of failures, but are rarely deployed due to their performance cost and complexity. In this work, we propose a new approach to designing high performance BFT protocols in data centers. By re-examining the ordering responsibility between the network and the BFT protocol, we advocate a new abstraction offered by the data center network infrastructure. Concretely, we design a new authenticated ordered multicast primitive (AOM) that provides transferable authentication and non-equivocation guarantees. Feasibility of the design is demonstrated by two hardware implementations of AOM -- one using HMAC and the other using public key cryptography for authentication -- on new-generation programmable switches. We then co-design a new BFT protocol, Matrix, that leverages the guarantees of AOM to eliminate cross-replica coordination and authentication in the common case. Evaluation results show that Matrix outperforms state-of-the-art protocols on both latency and throughput metrics by a wide margin, demonstrating the benefit of our new network ordering abstraction for BFT systems.