Improving Reliability for Application-Layer Multicast Overlays

Reliability of tree-like multicast overlays caused by nodes´ abrupt failures is considered as one of the major problems for the Internet application-layer media streaming service. In this paper, we address this problem by designing a distributed and light-weighted protocol named the instantaneous reliability oriented protocol (IRP). Unlike most of existing empirical solutions, we first define the overlay reliability problem formally, and propose a protocol containing a node joining algorithm (IRP-Join), a node preemption algorithm (IRP-Preempt), and a node switching algorithm (IRP-Switch) for reactively constructing and repairing the overlay, as well as proactively maintaining the overlay. With the formal problem presentation, we set up a paradigm for solving the overlay reliability problem by theoretically proving the effectiveness of our algorithms. Moreover, by comparing IRP with existing solutions via simulation-based experiments and real-world deployment, we show that IRP achieves a better reliability, while incurs fewer structural adjustments on the multicast overlay, thus, providing a superior overall performance.