Multicast group behavior in the Internet's multicast backbone (MBone)

The multicast backbone (MBone) is a network overlaying the global Internet and designed to support multipoint applications. In this article, the authors first give an overview of the development and architecture of the current MBone. One important characteristic of the MBone is its reliance on IP multicast which allows receivers to join and leave groups asynchronously. The authors describe the Mlisten data collection tool that was created to provide a mechanism for capturing information about when members join and leave a multicast group. Using data collected with Mlisten, the authors present statistics about some of the MBone sessions they monitored. Results are provided for key parameters including multicast participant interarrival times and participant durations, multicast tree size and characteristics, and intersession relationships. Collecting data about MBone usage can improve our understanding of how multicast communication and real-time protocols are being used today.