A Multicast Flow Control Protocol

Abstract

This paper describes the goals, approach, implementation, and performance of Mflow, a multicast flow control protocol. Our work focuses on the issues that arise from the increase in acknowledgments that occur as the size of the group grows. Mflow makes use of bulk acknowledgments to substantially reduce the number of acknowledgments per multicast message. It also staggers acknowledgments from different destinations to avoid storms of messages. We demonstrate that staggering can both decrease the number of acknowledgments needed for effective flow control as well as increase the robustness of the protocol to changes in the environment. We analyze both message and computation efficiency of Mflow. The protocol is computationally efficient and performs well in our experiments.