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Re: new editor's draft of WSA available

From: David Booth <dbooth@w3.org>
Date: Thu, 24 Oct 2002 18:38:57 -0400
Message-Id: <5.1.0.14.2.20021024183550.035b1da0@localhost>
To: "Christopher B Ferris" <chrisfer@us.ibm.com>
Cc: W3C WS Architecture <www-ws-arch@w3.org>

Some comments on the current Arch draft at
http://dev.w3.org/cvsweb/~checkout~/2002/ws/arch/wsa/wd-wsa-arch.html

Section 3.1 ". . . The service requestor uses a find operation to retrieve 
the service description locally or from the discovery agency (i.e. a 
registry or respository) and uses the service description to bind with the 
service provider and invoke or interact with the web service implementation."

This doesn't sound like it allows the possibility of a Service Requester 
obtaining the service description directly from the Service Requester, even 
though that possibility is made clearer later on.  I think it is important 
to point out more clearly here that the Service Requester could obtain the 
service description directly from the Service Provider.  I suggest the 
following wording change:

"The Service Requester obtains the service description either locally, 
directly from the Service Provider (if it is already known to the Service 
Requester), or it uses a find operation to retrieve the service description 
from a discovery agency (i.e. a registry or respository).  The Service 
Requester then uses the service description to bind with the Service 
Provider and invoke or interact with the Web Service implementation."

--------

Section 3.1.1. I have two suggestions on this section:

(a) The current definition of "The Service" is pretty confusing:
". . . The Service: Whereas a web service is an interface described by a 
service description, its implementation is the service. A service is a 
software module deployed on network accessible platforms provided by the 
service provider. It exists to be invoked by or to interact with a service 
requestor. It may also function as a requestor, using other web services in 
its implementation."

I would suggest the following definition:
"The Web Service (or "Service") is a software module that is deployed on 
network accessible platforms provided by the Service Provider. It 
implements the interface defined by the Service Description, and exists to 
be invoked by or to interact with a Service Requester.  It may also 
function as a Service Requester, in a peer-to-peer relationship."

(b) It bothers me to see both "The Service" and "The Service Description" 
in the same category called "Components", since one is an agent (or role) 
and the other is an artifact (or document).  I suggest changing the title 
of 3.1.1 to "Data" and moving the definition of "The Service" to section 
3.1.2 as a sub-definition under the definition of "Service Provider", since 
the Service is a part of (or owned by) the Service Provider.

--------

Section 3.1.2 The term "Service Provider" is defined to mean two very 
different things -- as the "owner of the service" and as a "service 
execution environment" -- and I think that introduces unnecessary 
confusion.  We should use different terms to refer to these different 
things.  The same problem exists for the term "Service 
Requester".  Furthermore, it seems strange to say that the "Service 
Provider" is an "execution environment", while the "Service Requester" is 
an "application".

I suggest using the following terms:
         "Provider Entity" to refer to the owner of the service.
         "Requester Entity" to refer to the owner of the client.
         "Provider execution environment" to refer to the service's 
execution environment (if needed).
         "Requester execution environment" to refer to the client's 
execution environment (if needed).
         "Requester Agent" to refer to the runtime application that the 
Requester Entity uses to invoke a Web Service.
         "Provider Agent" to refer to the runtime application that the 
Requester uses to implement the desired service.  ("Provider Agent" would 
therefore be a synonym for "Web Service".)

I am not married to these particular terms, but I do think it is important: 
(a) to use different terms for different concepts; and (b) to be consistent 
in our terminology.

Thanks,

-- 
David Booth
W3C Fellow / Hewlett-Packard
Telephone: +1.617.253.1273
Received on Thursday, 24 October 2002 18:38:59 GMT

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