© The authors - 6 - 19 April 2006
For Web services to interact properly with each other as part of composite applications that
perform more complex functions by orchestrating numerous services and pieces of informa-
tion, the requester and provider entities must agree both on the service description (WSDL
definition) and semantics that will govern the interaction between them. A complete seman-
tic solution requires that semantics are addressed not only at the terminology level but also
at the level that Web services are used and applied in the context of business scenarios, viz.
at the business process-level. This implies that there must be agreement between a service
requester and provider as to the implied processing of messages exchanged between inter-
acting services that are part of a business process.
Finally, Figure 1 illustrates that service modelling and service oriented engineering, i.e.,
service oriented analysis, design and development techniques and methodologies, are cru-
cial elements for the developing meaningful services and business process specifications and
an important requirement for SOA applications that leverage Web services. Service oriented
engineering activities help develop meaningful services, service compositions and tech-
niques for managing services. In other words they apply to the three service planes shown
in Figure 1.
The Services Research Roadmap in Figure 1 is also shown to define several roles. In addi-
tion to the classical roles of service client and provider it also defines the roles of service
aggregators and service operator (which will be explained in the material that follows).
Figure 1: Research planes in the Services Research Roadmap