An Evaluation of Shared Multicast Trees with Multiple Cores

Abstract

Native multicast routing protocols have been built and deployed using two basic types of trees: single-source, shortest-path trees and shared, core-based trees. Core-based multicast trees use less routing state compared to shortest-path trees, but generally have higher end-to-end delay and poor fault tolerance. In this paper we consider a new type of shared multicast structure that uses multiple, independent, simultaneously-active cores. Our design provides for low end-to-end delay, improved fault tolerance, and low source discovery delay, while balancing bandwidth cost and routing state. These results indicate that shared trees with multiple active cores are a viable alternative to shortest-path trees.