Furthermore, this model raises the
competition between service providers to force them into offering better services.
In the loosely coupled Web services architecture, the discovery process is the
key for dynamic service invocation. Universal description discovery and integration
(UDDI) (Von Riegen, 2002) plays the role of directory for the Web services??™
discovery. It consists not only of a data structure standard for all business-related
descriptions of services (i.e., service publication), but also the discovery protocols
that allow the service requester to gain access to the service publication and service
description. After the service requester chooses the service, he/she retrieves the
WSDL file to get its binding information and then invoke the target Web service
using SOAP protocol. These three standards form the basis of the Web services.
Most Web services??™ vendors support these standards to achieve the interoperability
between Web services. Additional protocols are designed on top of them to offer
value-added services.
As more and more Web services are published on the Web, the Web services??™ discovery
mechanism is becoming more and more important for several reasons.
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