Stack Summary
Currently, most of the work has been devoted to establishing and evolving the IDL-level of the service description stack. The WSDL approach has only recently been established, and it continues to gain adoption with better runtime support and tooling support from multiple vendors and use by developers.
The standards related to the nonfunctional description are still in their infancy. WSEL is only briefly mentioned as part of the WSFL specification. There is no other publicly available information on WSEL. The same is true for aggregation/orchestration; WSFL itself remains as a proposal in the area and has yet to undergo the rigors of submission and modification through an open standards body such as the W3C. We expect that standards in these layers of the service description stack will continue to evolve and mature.
To summarize, a Web service is described using a combination of techniques. A Web service's description is used to unambiguously answer several questions about the Web service. These questions and how they are addressed are summarized in Table 1.
Table 1: Roles of Each Layer of the Service Description Stack
Question |
Where Addressed |
Who |
Nonfunctional description |
What |
Service interface |
Where |
Service implementation |
Why |
Nonfunctional description |
How |
Service interface |