A Load Balancing Algorithm Based on Replication and Movement of Data Items for Dynamic Structured P2p Systems

Load balancing is one of the main challenges of every structured peer-to-peer (P2P) system that uses distributed hash tables to map and distribute data items (objects) onto the nodes of the system. In a typical P2P system with N nodes, the use of random hash functions for distributing keys among peer nodes can lead to O(log N) imbalance. Most existing load balancing algorithms for structured P2P systems are not adaptable to objects’ variant loads in different system conditions, assume uniform distribution of objects in the system, and often ignore node heterogeneity. In this paper we propose a load balancing algorithm that considers the above issues by applying node movement and replication mechanisms while load balancing. Given the high overhead of replication, we postpone this mechanism as much as possible, but we use it when necessary. Simulation results show that our algorithm is able to balance the load within 85% of the optimal value.