The Web services architecture is based upon the interaction between three components: a service provider, a service requester, and an optional service registry.
The registry is an optional component of the Web services architecture, because service requesters and providers can communicate without it. For example, the organization that provides a service can distribute the service description directly to the users of the service, using an attachment in an e-mail, a download from an FTP site, or a CD-ROM distribution.
Figure 1. Web service components and interactions
WebSphere Message Broker provides direct support for implementing the requester and provider components. You need additional software to deploy a service registry in WebSphere Message Broker. Because the Web service architecture is platform independent, you can, if you need a service registry, deploy it on another platform.