Locating relay nodes for P2P VoIP applications: A PlanetLab-based experimental study

In Peer-to-Peer VoIP applications, we can use relay nodes to detour default IP paths for recovering from low quality sessions (LQSs). Locating quality relay nodes (QRNs) rapidly and inexpensively however is a very challenging task. In this project, we present a PlanetLab-based experimental study on locating relay nodes. We collect the 1-hop QRNs of all LQSs in a network snapshot and evaluate a series of state-of-the-art QRN selection approaches. These evaluated schemas are either ineffective or involving excessive probes. We observe that LQSs with high location similarity tend to share QRNs. Inspired by this, we propose a geographic landmark (GLM) based system that uses delays from peers to landmarks and geographic constraints to select QRNs. Evaluations demonstrate that GLM outperforms the existing schemes in terms of cost efficiency.