Performance of Edge-Based Multicast Overlay Trees for Real Time MPEG Video Distribution*

Abstract: This work proposes an edge-node multicast overlay to create a tree capable of performing point to multipoint distribution of real time video (i.e., videoconference) with a hard upper bound on end-to-end delay. By moving the tree configuration, replication, and network monitoring to the edge routers instead of end systems, the trees can be constructed using the knowledge of overlay link bandwidths and latencies. As participants join the videoconference, several possible tree configurations are considered and a score based on latency and bandwidth utilization is assigned to each. The configuration with the highest score is chosen and constructed. All tree construction and content distribution is done without the use of native IP multicast. It is shown that by giving appropriate weights to both bandwidth and latency characteristics of a tree configuration, the sum of the packets lost due to congestion and excessive delay is significantly lower as compared to two existing multicast overlay implementations (YOID and Narada) without adding significant stress to higher utilized network links