<Open problems in Data sharing peer-to-peer systems>
Requirements of a p2p syutem can be specified in 3 main categories: Expressiveness, comprehensiveness, automony.
1. Expressivness. simple key lookup, keyword queries,(ranked keywords, aggregates) complex SQL queries.
2. Autonomy, efficiecy and robustness tradeoff between them.
Qos related to number of results, response time and results' relevance.
