Web services are a set of emerging standards that enable interoperable integration between heterogeneous IT processes and systems. You can think of them as a new breed of Web application that is self-contained and self-describing, and that can provide functionality and interoperation ranging from the basic to the most complicated business and scientific processes. In short, Web services hold the promise for providing a common standard mechanism for interoperable integration among disparate systems, and the key to their utility is their standardization. This common mechanism for delivering a "service" makes them ideal for implementing a Service-Oriented Architecture (SOA).
Besides using the common Web transports, Web services also require a common language for the data exchanged -- Extensible Markup Language (XML). Of course, XML is just the scaffolding for the actual exchange. For the Web services protocols to be interoperable across diverse systems and suitable for serious applications, standards bodies, such as W3C, OASIS, and WS-I, must formally standardize these protocols. IBM® continues to be a leader in and key contributor to that process. You'll see how this is relevant for Web services when you look at the breakdown of these standards and specifications below.
IBM's software patent licensing policies support widespread adoption of these standards. For more information, see the IBM Interoperability Specifications Pledge.
The following image gives a graphical representation of how all the categories of standards and specifications fit within the context of a Web services framework. Below it is a breakdown of the individual specs and how they relate to this framework:
BEEP, the Blocks Extensible Exchange Protocol (formerly referred to as BXXP), is a framework for building application protocols. It has been standardized by IETF and does for Internet protocols what XML has done for data.
These messaging standards and specifications are intended to give a framework for exchanging information in a decentralized, distributed environment.
Web services are meaningful only if potential users may find information sufficient to permit their execution. The focus of these specifications and standards is the definition of a set of services supporting the description and discovery of businesses, organizations, and other Web services providers; the Web services they make available; and the technical interfaces which may be used to access those services.
It is not possible to solve business issues if the participants are unable to be sure of the completion of message exchanges. Reliable messaging, which allows messages to be delivered reliably between distributed applications in the presence of software component, system, or network failures, is therefore critical to Web services.
Transactions are a fundamental concept in building reliable distributed applications. A Web service environment requires coordination behavior provided by a traditional transaction mechanism to control the operations and outcome of an application.
Using these security specifications, applications can engage in secure communication designed to work with the general Web services framework.
A business process specifies the potential execution order of operations from a collection of Web services, the data shared between these Web services, which partners are involved and how they are involved in the business process, joint exception handling for collections of Web services, and other issues involving how multiple services and organizations participate. BPEL specifies business processes and how they relate to Web services.
Web services manageability is defined as a set of capabilities for discovering the existence, availability, health, performance, usage, as well as the control and configuration of a Web service within the Web services architecture. As Web services become pervasive and critical to business operations, the task of managing and implementing them is imperative to the success of business operations.
As the area of Web services and SOA continues to evolve, there are a variety of categories for which new standards and specifications are being created. Some don't logically fit under the typical categories, so we list them here.