In many industries, companies
The primary benefit of SOA standards is that they make services interoperable , which means that services can communicate with one another, even if each implementation is written in a different computer language or is accessed by way of a different transport protocol (software that oversees the runtime transmission of data).
Standards also ensure that an SOA runtime product can support Quality of Service features, as described in Chapter 2.
SOA standards are
in the sense that any software manufacturer has the right to use those standards when developing an SOA-
Each company that works on an open standard seeks a text that matches the company's
Several major organizations oversee development of open standards for SOA:
Open Grid Forum ( http://www.ogf.org )
Organization for the Advancement of Structured Information Standards (OASIS; http://www.oasis-open.org )
Web Services Interoperability Organization (WS-I; http://www.ws-i.org )
World Wide Web Consortium (W3C; http://www.w3.org )
Later chapters give you practical insight into standards that are in effect or under consideration, and Appendix A describes several others.
Open standards are distinct from
, which is source code that you can learn from and use in your own projects, with certain legal restrictions. Open-source
is an application
Figure 1.1: Service-oriented application
The topmost level contains one or more
, each of which controls a flow of activities such as processing an
The second level is composed of services that each fulfill a relatively low-level business task. For example, an integration service might invoke such business services to verify the details provided by an insurance-policy applicant. If the business services return values that are judged to mean "issue a policy," the integration service invokes yet another business service, which calculates a quote and returns the quote to the software (for example, a Web application) that invoked the service-oriented application.
The third level consists of
Great complexity is possible. Some integration services, for example, provide different operations to different requesters, and some invoke other integration services and are said to be
of those services. Many applications, however, fulfill the