Spider: A BFT Architecture for Geo-Replicated Cloud Services

TL;DR

Spider introduces a modular BFT architecture for geo-replicated cloud services that reduces latency by leveraging cloud infrastructure features and a novel message-channel abstraction for efficient inter-group communication.

Contribution

The paper presents Spider, a new BFT architecture that minimizes complexity and latency in geo-distributed systems through independent replica groups and a novel message-channel abstraction.

Findings

Low response times achieved by geographically close replica groups.

Simplified system design via FIFO message channels with flow control.

Enhanced resilience and modularity in geo-replicated BFT systems.

Abstract

Traditionally, Byzantine fault tolerance (BFT) in geo-replicated systems is achieved by executing complex agreement protocols over large-distance communication links, and therefore typically incurs high response times. In this paper we address this problem with Spider, a resilient and modular BFT replication architecture for geo-distributed systems that leverages characteristic features of today's public-cloud infrastructures to minimize both complexity as well as latency. Spider is composed of multiple largely independent replica groups that each are distributed across different availability zones of their respective cloud region. This design offers the possibility to provide low response times by placing replica groups in close geographic distance to clients, while at the same time enabling intra-group communication over short-distance links. To handle the interaction between groups that is necessary for strong consistency, Spider uses a novel message-channel abstraction with first-in-first-out semantics and built-in flow control that greatly simplifies system design.