Overnesia: A Resilient Overlay Network for Virtual Super-Peers

Unstructured P2P networks have been widely used to implement resource location systems that support complex queries semantics. Unfortunately these systems usually rely on search algorithms based on some variant of flooding, which generate a significant amount of duplicate messages. An effective way to minimize the cost of query flooding in unstructured P2P networks is the use of super-peers. On the other hand, super-peers may become overloaded or may fail, and have a negative impact on the performance and connectivity of the overlay. These risks can be circumvented by replicating super-peers. Replication serves the dual purpose of supporting load distribution and fault-tolerance purposes. This paper proposes a novel algorithm to construct an overlay network connecting replicated super-peers. We have called the resulting overlay, Overnesia. The paper also proposes techniques to perform query routing that leverage on the unique properties of Overnesia to effectively distribute the query processing load among replicas.