Unfortunately, the majority target
the Web services development and production environment, while fewer address non-Web implementations.
Web standards include the Business Process Execution Language for Web Services
(BPEL4WS),6 Web Services Choreography Interface (WSCI), and the Web Services Choreography
Description Language (WS-CDL).7 There are two major mechanisms that can address service
synchronization efforts between consumers and services: orchestration and choreography.
1. Orchestration. This is a practice by which business process flow can be planned during
design-time and easily managed in run-time environments. Orchestration describes
how services interact with each other at the message level.8 This includes an invocation
sequence of messages and business activity behavior.
2. Choreography. The other industry standard is choreography that tracks a sequence of
messages involving multiple parties such as customers, suppliers, and partners. The distinction
is that choreography addresses the high-level collaboration of the various parties
involved in transactions, and on the relationship level in an enterprise or between business
partners that belong to different organizations.
The sections that follow describe three major service synchronization methods that influence
service design relationships.
IN-ORDER. Message exchange activities that take place between a service and its corresponding
consumers or peer services should be orchestrated if the sequence in which they are being executed
is important to achieving a certain goal.
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