ABR traffic management for point-to-multipoint connections entails that the source be controlled to the minimum rate supported by all the leaves of the multicast tree. A number of algorithms have been developed for extending ABR congestion avoidance algorithms to perform the feedback consolidation operation. This contribution discusses the various design options and implementation alternatives for the consolidation algorithms, and proposes a number of new algorithms that aim at providing a faster transient response, while eliminating the noise that may be caused if the feedback is returned before all leaves have responded. The performance of the proposed algorithms is compared to the performance of the previous algorithms under a large variety of conditions. In particular, configurations with varying bottleneck locations, link lengths, traffic and background traffic types are used to demonstrate the tradeoffs among the different algorithms. The results indicate that the new algorithms we propose completely eliminate the noise, while exhibiting a very fast transient response. Hence, although the algorithms have a slightly higher implementation complexity, they offer significant performance improvement.

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