DualCast: Protocol Design of Multiple Shared Trees Based Application Layer Multicast

This paper introduces a new approach to build application layer multicast overlay - multiple shared trees. Multiple shared trees´ approach makes tradeoffs between traditional source-based trees and single-shared tree, and between transmission efficiency and protocol overheads. Based on this, we propose two protocols to build ALM overlay among end users and media-forwarding-gateways respectively. The latter references the design thought of aggregated multicast to share the multicast trees among groups.