Beyond the Basics: Emerging Web Services Standards for Business Process Management

By Kelli Wiseth

Basic Web services are now able to provide core capabilities such as integration of heterogeneous applications and data, interoperability across disparate platforms, and reuse of business functionality in large part because the standards have matured—and they continue to mature. In addition, the Web Services-Interoperability organization doesn't produce any standards but, rather, codifies the sets of standards produced through OASIS or the W3C and how they should be used. The WS-I publishes guidelines ("profiles"), conformance tests, and other tools to help not only vendors but also Web services implementers ensure that the business services they build will be interoperable with others, regardless of the underlying implementation platform—Java or .NET, for example.

The WS-I's Basic Profile 1.0 (released in August 2003) specifies a set of standards and versions, such as HTTP 1.1, SOAP 1.1, WSDL 1.1, and XML 1.0, as well as usage for a basic Web service. For example, a Web service can make the contract under which it operates available in a variety of ways, but the Basic Profile 1.0 states, "The instance must be described using a WSDL 1.1 service description, by a UDDI binding template, or both." Security and reliability are the next two profiles being developed.

The WS-I is gaining strength, says Gartner's Whit Andrews, and Gartner clients are increasingly turning to the WS-I to help ensure that they create successful Web services. Oracle's Mike Lehmann, principal product manager for Oracle Application Server Containers for J2EE, concurs that Oracle customers and developers are also taking the WS-I seriously.

Furthermore, as basic Web services have taken hold in the enterprise, the demand for higher-order functionality is increasing. "We're starting to see that the more organizations have success with basic Web services, the more they begin to see the need for Web services security, Web services management, BPEL—the higher-level enterprise Web service standards," says Lehmann. "They're getting successful with the basic Web services, and they're ready to go to the next step."

Ultimately, the next several steps will lead to two broad types of process management that are complementary: the intra enterprise notion of "orchestration" and the enterprise-to-enterprise notion of "choreography." Orchestration covers the realm of a private process (or "private workflow") and ties together multiple Web services to build an executable process, typically internal to a company, says Lehmann. For example, a business process for handling a purchase order could require interaction between an inventory system, a credit service, and a shipping service. Choreography operates at a higher, public process level, says Lehmann, and is "tackling how different businesses can define which message exchange patterns they will engage in before implementing the corresponding internal process."

Here are some of the emerging standards that will facilitate or support such scenarios:

Business Process Execution Language (BPEL) is an XML-based workflow definition language, like XML 1.0, XML Schema, and WSDL, that defines a set of constructs for implementing executable business processes that support interaction between Web services—in other words, BPEL is a language for internal process automation (a.k.a. orchestration).

Web Services Composite Application Framework (WS-CAF) broadly encompasses all areas required to handle transactions, including transaction context, coordination, lifecycle, and message delivery. WS-CAF will complement Web services orchestration and choreography technologies, including BPEL (among others), and will also work with existing Web services specifications such as WS-Security and WS-Reliability.

WS-Security was formally approved by OASIS in April of this year and provides specifications for SOAP, X.509, and Username token profiles. Oracle is building a WS-Security implementation into the next release of Oracle Application Server 10g and also integrating it into Oracle JDeveloper 10g and the management console.

WS-Reliability will provide a generic, open model for ensuring reliable message delivery—the ability to guarantee message delivery to software applications (either Web services or Web service client applications) with a chosen quality-of-service (QoS) level for Web services.

Web Services Distributed Management (WSDM, pronounced "wisdom") is a vendor- and implementation-independent management infrastructure designed to treat heterogeneous Web services as manageable resources. A Web services implementation that supports WSDM will provide a set of Web services and operations for configuration, monitoring, and other management tasks.

---

Kelli Wiseth (kelli@alameda-tech-lab.com) is technology director at Alameda Tech Lab and Research Center (alameda-tech-lab.com).