Wang, Chih-chiang. Managing Heterogeneity in Structured Peer-to-peer Systems. (under the Direction of Assistant Professor Khaled Harfoush). Managing Heterogeneity in Structured Peer-to-peer Systems

WANG, CHIH-CHIANG. Managing Heterogeneity in Structured Peer-to-Peer Systems. (Under the direction of Assistant Professor Khaled Harfoush). Peer-to-Peer (P2P) systems account for more than 60% of today’s Internet traffic. P2P success is attributed to the virtually unlimited capacity offered by its members, the resilience to failures, and features such as anonymous service. P2P systems are inherently heterogeneous. Members may have different service capacities, different Internet connectivity speeds, and spend different times in the system. Heterogeneity impacts the scalability of P2P systems, its ability to serve user requests and the perceived user performance. P2P systems need to be engineered to accommodate node heterogeneity. In this dissertation, we present two studies on node heterogeneity in structured P2P systems. In the first study, we analyze routing performance in the presence of P2P overlay irregularity caused by the heterogeneous capacity of peers. We pinpoint how Greedy routing deviates from shortest path routes and propose a novel routing protocol, RASTER, which uncovers shortest routes in irregular overlays. In the second study, we provide an analytical model that captures the tradeoff between the stability and the scalability in P2P systems. We use the model to demonstrate that P2P instability can be mitigated and system throughput can be optimized through careful selection of serving members and data redundancy parameters. Our model reveals appropriate trends in engineering P2P systems under bandwidth and storage constraints, the skew in the size and popularity of maintained content, and the workload imposed on the system. We highlight the performance limitations of P2P systems as expressed in terms of the system throughput and response time to user requests in the presence of node instability. Our results challenge common wisdom about P2P systems, their appropriateness for different applications, and their virtually unlimited capacity. Managing Heterogeneity in Structured Peer-to-Peer Systems by Chih-Chiang Wang A dissertation submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the Degree of Doctor of Philosophy Computer Science Raleigh, NC 2007