Tuesday, December 17, 2002

Terminology: "Orchestration" and "Choreography"

I found an interesting email thread on some terminology that I thought I'd share.

From: "Sanjiva Weerawarana"
To: ,
Date: Wed, 14 Aug 2002 14:18:35 +0600
Subject: Re: "Orchestration" and "Choreography"

I'm not sure whether there's such a clear distinction between
the terms. During the lifetime of the BPEL4WS document, it was
at one point called WS-Orchestration, then WS-Choreography,
then WS-Business Process and and eventually BPEL4WS. I can tell
you that the name changes had nothing whatsoever to do with
technical distinctions between the words .. it was all marketing
and, um sometimes, politics ;-).

To me orchestration, choreography, business process, workflow
are all ways of indicating how to take a bunch of things and
put them together to do something meaningful. We also use the
term composition for the same thing .. BPEL4WS is a language
for composing a set of Web services into another service. The
thing that makes it a workflow language is that the composition
primitives chosen are those that are well-known in the workflow

Edwin's distinction seems to be the difference between what
WSFL called global models vs. flow models. I think that distinction
is definitely valid (BPEL4WS doesn't yet handle global models,
for example), but I don't think the terms choreography and
orchestration distinguish between those two.

Coordination is different IMO; that's really distributed
synchronization (rendezvous).

Hope this helps,



Later, I found this email which goes into some working definitions that the w3-arch group considered.

No comments: