Virtual Distance: A Generalized Metric for Overlay Tree Construction

Abstract—Overlay multicasting enabled many new overlay and peer-to-peer applications such as P2PTV, large-scale con-tent sharing, and live video streaming. Sensitivity of these applications differs against various network performance met-rics such as delay, loss, or bandwidth. We propose a gener-alized method of calculating overlay trees to increase user-perceived quality of performance-sensitive applications. We define and use the concept of virtual distance for constructing overlay trees. Abstracting applications ’ sensitivity to various performance metrics within the virtual distances, we aim to find the most appropriate parent for a peer according to the application’s purpose. Calculating the virtual distance based on different criteria, but without protocol modification, makes the overlay multicast protocol satisfy different quality expec-tations. We show by simulation experiments that the protocol automatically calculates overlay trees based on delay or loss, depending on which is more important for the application under consideration. 1 2 Keywords-overlay multicast; peer-to-peer; peer-to-peer TV; path stretch I