P2P网络环境下的一种高效虚拟协同服务模型

An Efficient Virtual Co-Allocation Service Model in P2P Networks

在现实网络中,资源主要集中在少数的重要节点中,大量节点是服务请求者.由于P2P网络是建立在Internet之上的应用层虚拟网络,加上网络中搭便车现象日益严重,在广域环境下,不可避免地存在拥塞、单点失效、效率和服务质量不高的问题.针对这些问题,通过在系统中动态地构造由协同服务盟员组成的服务池来解决.提出了一种有盟主的虚拟协同服务组织模型,旨在现实环境下针对盟主的目标需求,解决盟主如何动态组织自主的协同伙伴和构建虚拟组织协同进行求解的问题.构造了基于D-S证据推理的服务盟员选择策略,运用节点交易历史信息和推荐证书的方法来表征备选服务盟员的全局信任特征属性,给出了构建虚拟协同服务池的数学模型、约束条件和构造规则,并进行了较为详细的分析.仿真实验表明,动态构造服务池的负载平衡策略能较好地解决P2P网络中存在拥塞、单点失效、效率和服务质量不高的问题,极大地改善了P2P网络的服务质量.

In the realistic networks, resources are mainly concentrated in several important nodes, with a large number of nodes acting as the request of the service. Because P2P network is a virtual network based on application layer of the Internet, and free riding, under the wide area network environment, where unavoidably exist some problems such as congestion, node failure, low efficiency and quality of service （QoS）. In order to solve these problems, a scheme is provided, which dynamically constructs virtual co-allocation service pool that consists of service member coordination to achieve the load balance. A stakeholder-centric virtual organization model is put forward to cope with the problem of how to dynamically select autonomous partner＇s services and processes to form a virtual organization to satisfy the stakeholder＇s requirement in realistic networks. The scheme constructs the strategy of choosing the service member coordination based on D-S（Dempster-Shafer） evidence reasoning. It makes use of the historical trade information of nodes and recommendation certificate to show the spare service alliance＇s global trust character. Also provided are the virtual co- allocation service pool of mathematics model, constraint condition, constructional rule, and correlative analysis. The simulation results show that the scheme could effectively solve the above problems, and greatly improves the QoS of P2P network.