BPEL FAQs

Why BPEL?
A significant, industry-shaping event occurred on June 9, 2002 for web services technology. On that day, a coalition consisting of industry heavyweights IBM, Microsoft, OpenStorm and others released the Business Process Execution Language for Web Services (BPEL4WS) specification. BPEL is a 'service oriented language' that places integration and interoperability as a first order concern.


Business Value

BPEL4WS is a specification to standardize integration logic and process automation between Web Services. Process automation software is not new. However, a platform-neutral, standards-based approach using Web Services is new.

BPEL4WS is one of several new technologies and standards that have been released for Web Services. First generation Web Services enabled simple point-to-point integration using technologies like SOAP, WSDL, and UDDI. Newer technologies and standards are harnessing Web Services to create true enterprise-class business solutions that can encapsulate complex business logic while providing reliability, security and control.

The ability to deliver these enterprise capabilities while remaining platform-neutral and standards-based has caught the attention of software vendors and corporate customers alike. Of obvious interest are the huge costs savings and broad interoperability benefits that these technologies promise. Corporate strategists and enterprise architects are also enticed by the vastly improved agility and flexibility provided, enabling rapid development of new business processes and business models to capitalize on opportunities.


BPEL Foundations

BPEL4WS represents a convergence of language features from IBM's Web Service Flow Language (WSFL), who's control flow language is almost identical to IBM's MQ Series workflow language, and Microsoft's XLANG, which is used by Microsoft's BizTalk product. Both WSFL and XLANG are superseded by the BPEL4WS specification, with a range of new products leveraging the new specification under development.

In the spring of 2003, the BPEL 1.1 specification was formally submitted to the OASIS standards body. This move further ensured BPEL as the de-facto standard for web service orchestration and that the specification can be implemented on a royalty-free basis. OpenStorm was pleased to be a co-submitter of the BPEL 1.1 specification to OASIS.


Frequently Asked Questions

What is Web Service Orchestration (WSO)?

Web Service Orchestration is a category of software that facilitates application integration using web service standards. Previously, systems were integrated using proprietary solutions by vendors like Tibco, SeeBeyond, Vitria, Web Methods and others. Each vendor created their own adaptors and their own “integration logic”. These proprietary integration mechanisms have been replaced by specification-driven standards allowing customers to avoid vendor lock-in. The recent standardization of BPEL4WS has enabled a new breed of standard, interoperable integration platforms.

What is BPEL4WS?

BPEL4WS, also known as BPEL (rhymes with ripple), is an acronym for, “Business Process Execution Language for Web Services”. BPEL is the standard used to describe interactions between applications. BPEL is an XML based dialect that has strong semantics for describing message flows, asynchronous and parallel communications, and interaction with web services while leveraging the current set of XML and web service standards. BPEL is the successor to Microsoft’s XLang, which is used in BizTalk, and to IBM’s WSFL. Both XLang and WSFL will be phased out.

What kind of commands might I find in BPEL?

BPEL has commands for process flow control including While, Sequence, Pick, and Flow. It also has variables and faults. The ability to invoke web services is core, as well as the ability to listen for incoming messages from web services. Features for compensation handling, error/fault handling and event handling are built in. It contains most of the concepts found in simple scripting languages, but has a strong emphasis on working with XML, web services and long running processes.

What is an Orchestration?

An orchestration is a script that identifies partners, roles and logic to connect them all together. The orchestration script is often called a “schedule” or a process.

Why do I need to Orchestrate my web services?

Web Services have ‘contracts’ that define their capability and identify how to call them. This presents an opportunity to pipe one service into another, creating a chain of services that perform a greater function. BPEL allows one to chain together services to create an ‘aggregate service’ or to chain services together in order to manage the steps of a business process. This enables one to quickly connect a set of services in a loosely coupled, yet controlled and managed environment. As an organization matures in its use of BPEL, the orchestration scripts begin to become one of the most important artifacts. The scripts become the definition for how Web Services are connected. Orchestration scripts become a first-order artifact to identify ‘integration logic’.

Is Orchestration a type of SOI?

Yes, orchestration is a type of Web Service Based Integration. It is currently the favored means of connecting participants using open standards.

What is a Service Oriented Architecture (SOA)?

A service-oriented architecture is an architectural guideline that emphasizes communications that are:

  Message based – use of messages like SOAP with XML Schema
  Contract-based – use of interface definition languages like WSDL
  Protocol-based – use of complementary protocols like WS-I profiles

BPEL is a major participant in an SOA. In many ways, it acts as the brain of the loosely coupled system, making it all work together.