On the topology of multicast trees

• Published in: IEEE/ACM transactions on networking Vol. 11; no. 1; pp. 153 - 165
• Main Authors: Chalmers, R.C., Almeroth, K.C.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2003; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Assembly; Bandwidth; Computer science; Costs; Frequency measurement; IP networks; Multicast protocols; Network topology; Shape; Unicast
• ISSN: 1063-6692; 1558-2566
• DOI: 10.1109/TNET.2002.804835

The benefit derived from using multicast is seemingly dependent upon the shape of the distribution tree. We attempt to model interdomain multicast trees accurately. We measure a number of key parameters, such as depth, degree frequency, and average degree, for a number of real and synthetic data sets. We find that interdomain multicast trees actually do share a common shape at both the router and autonomous system levels. Furthermore, we develop a characterization of multicast efficiency which reveals that group sizes as small as 20 to 40 receivers offer a 55%-70% reduction in the total number of links traversed when compared to separately delivered unicast streams. A final contribution of our work consists in a number of data sets, compiled from multicast group membership and path data, that can be used to generate large sample trees, representative of the current multicast infrastructure.