Abstract: A hierarchy available service computing framework is proposed in this article.It is composed of 3 layers which are organically integrated，i.e.the service-registration layer，the virtual service layer and the real service layer.The service-registration layer and the virtual service layer together compose the available service framework，which fulfills the registration of service，detecting validity of service，organizing service and treats the available configuration parameters as the one attribute of the framework，and the system can dynamically configure according to the available attribute automatically，and make it meet the needs of application.The framework，the implementing mechanism and the organizing protocol of that model are particularly described in this article.The analysis of the model and the simulations carried on the prototype demonstrate the validity of the model.

Key words: services oriented, availability, architecture, support system, dynamic configuration

摘要： 提供可用的服务是面向服务计算的关键技术。文章提出了一种层次性可用服务计算结构框架，它由服务注册层，虚拟服务层，真实服务层三个有机结合的层面组成。服务注册层和虚拟服务层共同组成可用服务框架，由可用服务框架完成服务的注册，服务有效性检测和组织，由系统自动地根据可用属性来动态配置，使其满足应用的需要，从而达到可用计算的目的。文章详细描述了该模型的结构框架、实现机制、组织协议，通过对模型的分析和模拟表明了该模型的有效性。

关键词: 面向服务, 可用性, 结构模型, 支撑平台, 动态配置