Evaluation of P2P resource discovery architectures using real-life multi-attribute resource and query characteristics

Emerging collaborative Peer-to-Peer (P2P) applications rely on resource discovery solutions to aggregate groups of heterogeneous, multi-attribute, and dynamic resources that are distributed. In the absence of data and understanding of real-life resource and query characteristics, design and evaluation of existing solutions have relied on many simplifying assumptions. We first present a summary of resource and query characteristics from PlanetLab. These characteristics are then used to evaluate fundamental design choices for multi-attribute resource discovery based on the cost of advertising/querying resources, index size, and load balancing. Simulation-based analysis indicates that the cost of advertising dynamic attributes is significant and in-creases with the number of attributes. Compared to uniform queries, real-world queries are relatively easier to resolve using unstructured, superpeer, and single-attribute dominated query based structured P2P solutions. However, they cause significant load balancing issues in all the designs where a few nodes are mainly involved in answering majority of queries and/or indexing resources. Moreover, cost of resource discovery in structured P2P systems is effectively O(N) as most range queries are less specific. Thus, many existing design choices are applicable only under specific conditions and their performances tend to degrade under realistic workloads.