The WS Choreography Model describes the data and the relationships between them that is needed to define a choreography that describes the sequence and conditions in which the data exchanged between two or more participants.
WSDL (new window) and its extensions provide a mechanism by which the first objective is realized, however, it does not define the sequence and conditions, or choreography, in which messages are exchanged. To solve this problem, a shared common or "global" definition of the sequence and conditions in which messages are exchanged is produced that describes the observable complementary behavior of all the participants involved. Each participant can then use the definition to build and test solutions that conform to the global definition. The main advantage of a global definition approach is that it separates the process being followed by an individual business or system within a "domain of control" from the definition of the sequence in which each business or system exchanges information with others. This means that, as long as the "observable" sequence does not change, the rules and logic followed within the domain of control can change at will.
The WS Choreography Model is an information model or "meta model" for the WS Choreography Description Language (WS-CDL) (new window) that identifies the information and structures required to build a "global" definition.
Organization: W3C
More information: WS Choreography Model page on the W3C website (new window)
More on the general topic: Models and metamodels
