Proceedings

Abstract:

Several Web service discovery technologies including Universal Description, Discovery and Integration (UDDI), Web Services Metadata Exchange (WS-MEX) and other lightweight protocols and techniques can be used for particular scenarios. This presentation will discuss the status of each of these technologies and how they relate to the Web services stack as well as which technology should be employed to solve certain types of Web service integration problems.

UDDI is set of OASIS standards that describe a registry for publishing a Web service "index" for discovery and is implemented in the WebSphere Application Server. UDDI can be used as an integration point for Web service development by following best practices for modeling including indexing WSDL into UDDI structures for discovery. The UDDI structures resulting from this modeling can be enhanced to further classify the Web service according to any number of taxonomies. Since UDDI is not specifically restricted to Web services, several companies use UDDI to model a business process with several different technical interfaces so that clients with different capabilities and business needs can select the most suitable and best performing service. This use case is primarily driven by a desire to organize infrastructure as distinct services and index them in a single location. A similar use case that extends beyond development time is where UDDI is used to find the gateway and routing for late client binding when a specific service interface is queried requested the registry. The modeling techniques also apply to controlled public registries and this presentation will briefly discuss public projects targeted at accelerating web service adoption on the Internet. This presentation will discuss the capabilities of the UDDI standard as they relate to these and other use cases.

The complexity of the APIs and sometimes static nature of the data in UDDI do not fit all discovery scenarios, and while some of this may be solved through using a UDDI registry with different policies and modeling, some cases are best solved using other technologies that are in development. One of these technologies is WS- MEX which allows for Web service bootstrapping for a Web service known through a specific Web Services Addressing reference. This lighter weight discovery mechanism is necessary for discovering WSDL, XML Schema and Policy in cases where a specific reference is passed to a client. This paper will discuss when WS-MEX is more appropriate than using an external registry such as UDDI and also the cases where data in UDDI should correspond to data for a WS-MEX service.

The last use case to be discussed is client bootstrapping over a lightweight protocol. The technologies available for lightweight discovery and use cases are changing rapidly and the current state of the technologies at the time of the presentation will be discussed.