Saturday, November 13, 2004
Web Services, Orchestration and Choreography
From initial reading of Web services workflow technologies, I am completely confused regarding the difference between Orchestration and Choreography.
What is the difference between Web services orchestration and choreohraphy? From my various readings this is the best description I could find:
"Existing specifications for Web services describe the indivisible units of interactions. It has become clear that taking the next step in the development of Web services will require the ability to compose and describe the relationships between lower-level services. Although differing terminology is used in the industry, such as orchestration, collaboration, coordination, conversations, etc., the terms all share a common characteristic of describing linkages and usage patterns between Web services. For the purpose of this document, and without prejudice, we use the term choreography as a label to denote this space."
"Choreography" and "orchestration" are in my view synonymous. Other synonymous terms include "workflow" and "business process automation". All of these terms refer to automatic routing of content, context, and control through a series of distributed business processes.
What is the difference between Web services orchestration and choreohraphy? From my various readings this is the best description I could find:
- Choreography - Web services choreography pertains to the public protocol of a Web service, describing the nature and order of messages exchanged between a Web service and its consumers or peers. WSCI (Web Services Choreography Interface), proposed by BEA and Sun as a specification aimed at describing the flow of messages among interacting Web services and is a Choreography specification.
- Orchestration - Web services orchestration, on the other hand, pertains to the private implementation of a Web service, i.e. describing and executing the interactions and flow among Web services to form collaborative processes or (long-running) business transactions. BPEL4WS (Business Process Execution Language for Web Services) proposed by IBM and Microsoft is an Orchestration specification.
All these technologies are used to construct business processes on top Web services enabling technologies such as SOAP, WSDL, UDDI etc. Both Orchestration and Choreohraphy provide collaboration and coordination mechansim between business.
From Web Services Choreography Working Group Charter the following comment best describes the orchestration and choreohraphy:"Existing specifications for Web services describe the indivisible units of interactions. It has become clear that taking the next step in the development of Web services will require the ability to compose and describe the relationships between lower-level services. Although differing terminology is used in the industry, such as orchestration, collaboration, coordination, conversations, etc., the terms all share a common characteristic of describing linkages and usage patterns between Web services. For the purpose of this document, and without prejudice, we use the term choreography as a label to denote this space."
"Choreography" and "orchestration" are in my view synonymous. Other synonymous terms include "workflow" and "business process automation". All of these terms refer to automatic routing of content, context, and control through a series of distributed business processes.
