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WS-CDL or abstract BPEL

From: Tonny Holdorf <tonny.holdorf@gmail.com>
Date: Thu, 1 Dec 2005 09:20:39 +0100
Message-Id: <462F9F3D-A89D-454D-AD9E-F1DA8B31AC3B@gmail.com>
To: public-ws-chor@w3.org

Hello everybody,

I am totally new to this community, so please bear with me if I have  
gotten something wrong.

I am trying to get a view of the pros and cons of WS-CDL versus  
abstract BPEL for modeling business collaborations and protocols. In  
a thread on the Theserverside:

http://www.theserverside.com/news/thread.tss?thread_id=37760

Steve Ross-Talbot linked to the paper by Marco Carbone Kohei Honda  
and Nobuko Yoshida. Reading the paper made me wonder if the WS-CDL  
and the abstract BPEL work groups and specifications are pursuing the  
same goal. Steve suggested that I post my questions here. So here  
they are:


In the paper linked to above (i.e. the paper by Marco Carbone Kohei  
Honda and Nobuko Yoshida) two formal calculi are described: a  
'global' calculus that models business processes from a global  
perspective and the pi-calculus that models the same processes as a  
set of local endpoint behaviors. The global calculus is similar to WS- 
CDL and the main point of the paper is that processes modeled with  
the global calculus (WS-CDL) can be translated to the pi-calculus.

Reading the paper made me wonder: Why is a global description of the  
service collaboration as in WS-CDL better than a set of local  
descriptions that each describes the behavior of the participating  
services (e.g. as a set of abstract BPEL descriptions)? Would a set  
of abstract BPEL descriptions for each of the collaborating services  
and a global WS-CDL description for the collaboration as a whole not  
just be different representations of the same thing? If not, what  
expressive power is added by the global WS-CDL description compared  
to a set of abstract BPEL descriptions for each end point.

Also, many complicated network protocols, e.g. TCP, have been  
specified just fine by descriptions of endpoint behavior such as  
state machines. Why is a global specification needed?


Best Regards

Tonny
Received on Thursday, 1 December 2005 12:34:51 GMT

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