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RE: Web Service Definition [Was "Some Thoughts ..."]

From: James M Snell <jasnell@us.ibm.com>
Date: Fri, 1 Mar 2002 16:20:30 -0700
To: "Vinoski, Stephen" <steve.vinoski@iona.com>
Cc: www-ws-arch@w3.org
Message-ID: <OFC3924D4F.91DF13F7-ON88256B6F.007F210C@boulder.ibm.com>
Stephen,

We actually are on the same page here.  We both seem to agree that yes, 
Web services can be described and discovered, but we disagree whether or 
not those properties need to be called out explicitly in the definition. 
You seem to be saying no, I'm saying yes they do.  The reason is the same 
as why we explicitly define Web resources as having unique URI 
identifiers.  Of course Web resources have identifiers, they're objects 
and all objects have identifiers -- of what use is it to explicitly call 
out that point?  The answer is that by stating the fact, we lay the 
groundwork for standardizing how those identifiers are created, 
represented, communicated, etc.  We're basically stating that Web 
resources need to have a standardized method of identification.  For Web 
Services, explicitly calling out description and discovery as properties 
of a Web service indicate that there needs to be standardized mechanisms 
for description and discovery -- regardless of whether or not every Web 
service actually implements those standards.  Because a Web Service can be 
described and discovered, the overall Web Services Architecture needs to 
take into account standardized mechanisms for description and discovery. 
I'm not saying we have to create such standards here, just acknowledge 
their existence and role.  Make sense?

- James M Snell/Fresno/IBM
    Web services architecture and strategy
    Internet Emerging Technologies, IBM
    544.9035 TIE line
    559.587.1233 Office
    919.486.0077 Voice Mail
    jasnell@us.ibm.com
 Programming Web Services With SOAP, O'reilly & Associates, ISBN 
0596000952 

==
Have I not commanded you?  Be strong and courageous.  Do not be terrified, 

do not be discouraged, for the Lord your God will be with you wherever you 
go.  
- Joshua 1:9

To:     James M Snell/Fresno/IBM@IBMUS
cc: 
Subject:        RE: Web Service Definition [Was "Some Thoughts ..."]



Given that you won't be able to prove it, let's look at it in a
practical manner. Everything in the universe is both describable and
discoverable. Therefore, speaking about D&D generally does not add any
clarity to the definition. On the other hand, if you're speaking
specifically about discovery services like UDDI and description services
like WSDL, then that too is wrong, as I know of several web services
already in production that use neither WSDL nor anything like UDDI.

--steve

> -----Original Message-----
> From: James M Snell [mailto:jasnell@us.ibm.com]
> Sent: Friday, March 01, 2002 3:57 PM
> To: Vinoski, Stephen
> Subject: RE: Web Service Definition [Was "Some Thoughts ..."]
>
>
> 100% of all Web resources, including Web Services CAN be
> described and
> discovered.  The differentiating factor is HOW.  Every Web
> service CAN be
> discovered regardless of whether or not the Web service explicitly
> supports a specific discovery mechanism.  Every Web service CAN be
> decribed regardless of whether or not the Web service
> explicity supports a
> specific description mechanism.  You are right in that decription and
> discovery alone do not distinguish Web services from other
> types of web
> resources, but that does not mean that the properties of
> discoverability
> and description are not part of the formal definition of a
> Web service.
>
> - James M Snell/Fresno/IBM
>     Web services architecture and strategy
>     Internet Emerging Technologies, IBM
>     544.9035 TIE line
>     559.587.1233 Office
>     919.486.0077 Voice Mail
>     jasnell@us.ibm.com
>  Programming Web Services With SOAP, O'reilly & Associates, ISBN
> 0596000952
>
> ==
> Have I not commanded you?  Be strong and courageous.  Do not
> be terrified,
>
> do not be discouraged, for the Lord your God will be with you
> wherever you
> go.
> - Joshua 1:9
>
> To:     James M Snell/Fresno/IBM@IBMUS, "Joseph Hui"
> <jhui@digisle.net>
> cc:     <www-ws-arch@w3.org>
> Subject:        RE: Web Service Definition [Was "Some Thoughts ..."]
>
>
>
> > -----Original Message-----
> > From: James M Snell [mailto:jasnell@us.ibm.com]
> > Sent: Friday, March 01, 2002 1:21 PM
> > To: Joseph Hui
> > Cc: www-ws-arch@w3.org
> > Subject: RE: Web Service Definition [Was "Some Thoughts ..."]
> >
> >
> > A Web Service must be defined as having the properties that
> it can be
> > decribed and discovered.  Both the Web service and it's
> > description must
> > be discoverable.
>
> No, and no. This thread of email already contain multiple explanations
> of why.
>
> > Definition ==> A Web service can be described and discovered.
>
> As I've already explained using real-world examples, neither
> of these is
> necessarily true (other than the discovery via URI that Mark
> mentioned).
>
> Neither discovery (as in UDDI-like services) nor description
> distinguish
> Web Services from prior art, nor are they found in 100% of
> existing Web
> Services systems. They are therefore not needed to define Web
> Services.
>
> --steve
>
> >
> > - James M Snell/Fresno/IBM
> >     Web services architecture and strategy
> >     Internet Emerging Technologies, IBM
> >     544.9035 TIE line
> >     559.587.1233 Office
> >     919.486.0077 Voice Mail
> >     jasnell@us.ibm.com
> >  Programming Web Services With SOAP, O'reilly & Associates, ISBN
> > 0596000952
> >
> > ==
> > Have I not commanded you?  Be strong and courageous.  Do not
> > be terrified,
> >
> > do not be discouraged, for the Lord your God will be with you
> > wherever you
> > go.
> > - Joshua 1:9
> >
> > Sent by:        www-ws-arch-request@w3.org
> > To:     <www-ws-arch@w3.org>
> > cc:
> > Subject:        RE: Web Service Definition [Was "Some Thoughts ..."]
> >
> >
> >
> > By now IMHO we the WG have made the progress that D&D ought to be
> > in the def.  (Have we not?  I don't want to be presumptuous here.)
> > So the issue to be settled is whether D&D is already accounted for
> > in URI.
> >
> > In my view URI is for addressability.  A globally unique ID offers
> > no intrinsic value to a resource's discovery.  E.g. there's no way
> > johny, seeking to buy books, can discover a book seller by
> > inferring from a URI like http://www.amazon.com.
> > Mark's made some good points; yet I find the
> > "D&D-accounted-for-in-URI"
> > argument too tenuous.  Withi the web context, D&D is an integral
> > (as Sandeep put it) part of WS.  It's not a property that can be
> > assumed by default, thus calling it out is warranted.
> >
> > Cheers,
> >
> > Joe Hui
> > Exodus, a Cable & Wireless service
> > =========================================
> >
> > > -----Original Message-----
> > > From: Mark Baker [mailto:distobj@acm.org]
> > > Sent: Friday, March 01, 2002 6:53 AM
> > > To: Sandeep Kumar
> > > Cc: Vinoski Stephen; Joseph Hui; www-ws-arch@w3.org
> > > Subject: Re: Web Service Definition [Was "Some Thoughts ..."]
> > >
> > >
> > > Sandeep,
> > >
> > > > If D&D are not an integral part of a Web Service defintion,
> > >
> > > I was claiming that discoverability *is* an integral part of the
> > > definition.  It's just already accounted for by defining
> that a Web
> > > service be URI identifiable.
> > >
> > > I know this is a bit different than some Web service work
> > people have
> > > already done, but this is (IMO) one of those times where our
> > > mandate to
> > > be integrated with Web architecture effects our work.
> > >
> > > > pl help me define
> > > > how would you define a Web (or a Network) of Web Services,
> > > the participants.
> > > >
> > > > At a high-level, they must at least have the same
> > > characteristics. If not,
> > > > it would be much harder to reason about them
> > semantically, deal with
> > > > managing & monitoring them.
> > >
> > > Sorry, I'm unclear what you're asking.
> > >
> > > MB
> > > --
> > > Mark Baker, Chief Science Officer, Planetfred, Inc.
> > > Ottawa, Ontario, CANADA.      mbaker@planetfred.com
> > > http://www.markbaker.ca   http://www.planetfred.com
> > >
> >
> >
> >
> >
>
>
> 
Received on Friday, 1 March 2002 18:20:42 GMT

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