Bimodal multicast

TLDR

Existing multicast protocols range from strict all‑or‑nothing guarantees to best‑effort local repair, yet none explicitly treat delivery stability as a core reliability property needed for applications such as internet radio or conferencing. This work aims to develop a multicast protocol that offers rigorously quantified reliability, including throughput‑stability guarantees. The authors introduce bimodal multicast, a protocol whose reliability model is based on bimodal probability distributions, and provide theoretical analysis, experimental validation, and discussion of potential applications. Experiments confirm that bimodal multicast is reliable, scalable, and delivers remarkably stable throughput.

Abstract

There are many methods for making a multicast protocol “reliable.” At one end of the spectrum, a reliable multicast protocol might offer tomicity guarantees, such as all-or-nothing delivery, delivery ordering, and perhaps additional properties such as virtually synchronous addressing. At the other are protocols that use local repair to overcome transient packet loss in the network, offering “best effort” reliability. Yet none of this prior work has treated stability of multicast delivery as a basic reliability property, such as might be needed in an internet radio, television, or conferencing application. This article looks at reliability with a new goal: development of a multicast protocol which is reliable in a sense that can be rigorously quantified and includes throughput stability guarantees. We characterize this new protocol as a “bimodal multicast” in reference to its reliability model, which corresponds to a family of bimodal probability distributions. Here, we introduce the protocol, provide a theoretical analysis of its behavior, review experimental results, and discuss some candidate applications. These confirm that bimodal multicast is reliable, scalable, and that the protocol provides remarkably stable delivery throughput.