Web services 是一系列相互关联的应用函数，它们可以在Internet上被调用。Web services 是独立的、可以自己解释自己的组件，可以在Web上发布、定位、和调用。

Web services 的种类可以为三种：

1、共享商业信息。如：新闻、天气预报、股票行情等。
2、商业集成。如：网上拍卖、预订系统、信用校验等。
3、商业流程扩展。如：合并企业的制造、批发、零售等业务流程。

Web services 的业务角色和交互

可以分为service provider, service broker, and service client

Service providers create and deploy their Web services and can publish the availability of their WSDL-described services through a service registry, such as a UDDI Business Registry.

service provider主要是建立发布Web services。

Service brokers register and categorize published services and provide search services. For example, UDDI acts as a service broker for WSDL-described Web services.

Service brokers 是归类并注册Web services，以利于查询。

Service clients use broker services such as the UDDI Business Registry to discover a needed WSDL-described service and then bind to and call the service provider.

Service clients 则是在Service brokers中查找到Web services，然后绑定到Service providers并调用之。

可以参考www.ibm.com/developerworks/webservices