Abstract

Traditional reliable multicast protocols depend on assumptions about flow control and reliability mechanisms, and they suffer from a kind of interference between these mechanisms. This in turn affects the overall performance, throughput and scalability of group applications utilizing these protocols. However, there exists a substantial class of distributed applications for which the throughput stability and scalability guarantees are indispensable. Bimodal Multicast (Pbcast) is a new option in scalable reliable multicast protocols that uses an inverted protocol stack approach, in which probabilistic mechanisms are used at low layers, and reliability properties introduced closer to the application. The main contributions of this study are development of simulation models for performance evaluation of Bimodal Multicast, demonstration of how the inverted protocol stack approach works well on several network settings, and its comparison with best-effort reliable multicast mechanisms. Analysis results reveal that Bimodal Multicast, together with optimizations for improving its latency and reliability characteristics, scales well, exhibits stable throughput and in contrast to the other scalable reliable multicast mechanisms it gives predictable reliability even under highly perturbed conditions.

Author Keywords: Bimodal multicast (Pbcast); Multicast loss recovery; Scalable group communications; Protocol performance evaluation; Scalable reliable multicast (SRM)

Article Outline

1. Introduction

2. Inverted protocol stack and related work

3. Bimodal multicast protocol

3.1. Protocol execution

3.2. Implementation

3.3. Comparison of Bimodal Multicast and SRM

4. Optimizations to Bimodal Multicast

4.1. Pbcast-ipmc

4.2. Pbcast-grb

4.3. Pbcast-local

5. Performance analysis results

5.1. Multicast message inter-arrival distributions

5.2. Impact of limited bandwidth on routers: background overhead and latency distribution

5.3. Impact of Pbcast-local on application level latencies

5.4. Conditions causing multicast message congestion

6. Discussion

7. Conclusions

Acknowledgements

References

Vitae

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