Evaluating Underlay Performance of Optimal Overlay Multicast

Overlay multicast is regarded as a promising way for distributing file or live stream during recent years. In this paper, we reinforce an optimal DAGs (directed acyclic graphs) construction algorithm by relaxing its partitioning and sorting conditions. We employ a realistic topology (CERNET2 backbone) to evaluate several typical types of optimal DAGs in terms of the underlay performance metrics. Simulation results show that, both the maximum link utilization and the overall cost will decrease with the increasing of the number of sub streams. The link utilization curves appear similar even though the ways of partitioning and sorting nodes are different. Although the application layer and the network layer are designed to be transparent to each other, some characteristics of the overlay topologies can also be reflected in the underlay.