Context and Concept of Web Services

Abstract

The term Web services has as many definitions as there are people who have worked on it. The different definitions, in general, stress various aspects of Web services. The diverse nature of these definitions confirms the diverse interpretations of Web services (“Evolution of Integration Functionality,” 2001; Freger, 2001; Infravio, 2002; Ogbuji, 2002; Stal, 2002; Wilkes, 2002). The big computer giants such as Microsoft and IBM promote Web services, and the definitions offered by them are as follows. • IBM: “A Web Service is a collection of functions that are packaged as a single entity and published to the network for use by other programs...[They are] self-describing, self-contained, modular applications...” (Glass, 2000). • Microsoft: “Web Services are a very general model for building applications and can be implemented for any operating system that supports communication over the Internet and represent black-box functionality that can be reused without worrying about how the service is implemented...[They use] building blocks for constructing distributed Web applications...” (Kirtland, 2001). • World Wide Web Consortium (W3C): “A software system identified by a URI [uniform resource indicator], whose public interfaces and bindings are defined and described using XML [extensible markup language]. Its definition can be discovered by other software systems. These systems may then interact in a manner prescribed by its definition, using XML based messages conveyed by internet protocols” (W3C, 2002). This article attempts to clarify these generic definitions into language that is tangible and meaningful to the reader. To do so, background is given on the systems, applications, and architecture that led to the need and development of Web services.