基于信任的P2P拓扑进化机制

Effective Trust-based Topology Evolution Mechanism for P2P Networks

现有的非结构Peer-to-Peer(P2P)系统缺乏对拓扑公平性的考虑,并且不能对某些节点的恶意行为进行有效的抑制。其主要原因在于构造的拓扑对节点信任度的不敏感性,忽略了P2P网络中各节点的异构性。据此,首先给出了基于反馈可信度的节点全局信任度计算模型,然后在此基础上提出了一种针对非结构化P2P网络的自适应拓扑进化机制。利用该机制,可使高可信节点占据拓扑的有利位置,低可信节点处于不利位置,从而体现拓扑的公平性。该机制同时能够对节点的恶意行为进行有效的抑制,并具有激励性质,鼓励节点提供更好的服务,以获得更高的响应率。分析和仿真结果表明,该机制较之现有机制,在拓扑的有效性和激励性上有较大的提高。

Current unstructured peer-to-peer （P2P） systems lack fair topology structures,and take no consideration for malicious behaviors of peers. The main reason is that the topology is not sensitive to peer＇s trust,and cannot accommodate heterogeneity of peers over the network. Thus, a feedback credibility based global trust model was presented. Then,based on the trust model, an adaptive topology evolution mechanism for unstructured P2P networks was proposed. Through this mechanism, trusted peers can migrate to the centric position,while untrusted peers to the edge of the topology, guaranteeing fairness during topology evolution. On the other hand, the mechanism can effectively counter the malicious behaviors of peers, and also has the incentive functionality, which incents peers to provide more high-quality services in order to get more return on services. Analysis and simulations show that, compared with the current topologies, the resulting topology mechanism is more effective and robust in combating the selfish or malicious behaviors of peers.