Building Content-Based Publish/Subscribe Systems with Distributed Hash Tables

Building distributed content–based publish/subscribe systems has remained a challenge. Existing solutions typically use a relatively small set of trusted computers as brokers, which may lead to scalability concerns for large Internet–scale workloads. Moreover, since each broker maintains state for a large number of users, it may be difficult to tolerate faults at each broker. In this paper we propose an approach to building content–based publish/subscribe systems on top of distributed hash table (DHT) systems. DHT systems have been effectively used for scalable and fault–tolerant resource lookup in large peer–to–peer networks. Our approach provides predicate–based query semantics and supports constrained range queries. Experimental evaluation shows that our approach is scalable to thousands of brokers, although proper tuning is required.