The Spread Wide Area Group Communication System
Yair Amir, Jonathan Stanton · 2007
Building a wide area group communication system is a challenge. This paper presents the design and protocols of the Spread wide area group communication system. Spread integrates two low-level protocols: one for local area networks called Ring, and one for the wide area network connecting them, called Hop. Spread decouples the dissemination and local reliability mechanisms from the global ordering and stability protocols. This allows many optimizations useful for wide area network settings. Spread is operational and publicly available on the Web. 1. Introduction There exist some fundamental difficulties with high-performance group communication over wide-area networks. These difficulties include: . The characteristics (loss rates, amount of buffering) and performance (latency, bandwidth) vary widely in different parts of the network. . The packet loss rates and latencies are significantly higher and more variable then on LANs. . It is not as easy to implement efficient reliability...