Choreography is the global protocol governing the interaction of SOA processes partnering to achieve some business end. These processes generally span multiple organizations. Choreography is expressed in the form of a process, but it is not meant to actually run. It does not participate in the live message exchange. It functions instead as a set of traffic rules governing the participant processes.

An orchestration process is a process whose principal job is to build a flow of control around its interactions with partners. Not all orchestrations are subject to a choreography, but when a choreography exists, the structure of the orchestration process can be derived from that choreography.

An orchestration process has public and private activities. Public activities interface with external partners. If the process is subject to a choreography, the public activities are the ones required by the choreography. Private activities exist to meet internal requirements.

WS-CDL is the dominant...