Research On Load Balancing In Structured Peer To Peer Networks

Structured P2P network is a distributed network. The imbalanced needs of the storage resources and computer processing power heterogeneity may results system’s load imbalances. Single point failure, request delay and network congestion are often caused by this phenomenon. Dealing with P2P network’s load imbalance issues effectively is positively significant to promote the network performance and guarantee service quality.In structured P2P network, the load of a node consists of requesting load which comes from response to query messages and routing load which results from node’s transmitting query messages. The current research pays high attention alone to the former or the last. Based on this phenomenon, this paper focuses on load balancing of Chord and proposes Neighbor Group and Balance Group Mechanism (NBM), considering both request load and routing load.The NBM proposed can dynamically diagnose the probable existing "hot spots" nodes, and orginize them with their around nodes to create the Neighbor Groups respectively, and the nodes in which are further divided into Balancing Group according to the node processing capability. To access "hot" problems, the paper proposes copies transfer algorithm based on duplicating technology. In this algorithm, firstly nodes status are checked dynamically in balanced groups and the lightest nodes are selected; Secondly,"lightest" nodes are organized into a light ring; Last, the copies of the overload nodes are transferred to the light ring, meanwhile the copies are managed dynamically. At the same time, to routing "hot" problems, the paper advices an input degree adjusting algorithm. The second algorithm realizes load balance by transferring input degree from hot node to light node in neighbour groups or between them.In the last part of this paper, Peersim simulator is used to simulate the self-adaptive NBM. Based on the performance data, such as query hit rate, average delay, average system load, the effects of the NBM on load balance of Chord are analyzed. It can be seen from the simulation results; the mechanism improves "hot spots" problems in Chord, and effectively reduces the quantity of failure query.