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RE: arch diagrams from the f2f

From: Heather Kreger <kreger@us.ibm.com>
Date: Thu, 19 Sep 2002 21:55:51 -0400
To: www-ws-arch@w3.org, jones@research.att.com
Message-ID: <OF6AA6EB6A.D263BAC1-ON85256C3A.0009F355@us.ibm.com>





Very interesting points,
So, we have two concepts to bring in:

1. Service Provider Description
We have distinguished between service and service provider in the diagram.
The service is the oval.

When we were 'counting' on UDDI as the registry, we used to say that a
'complete description' was created
by adding the business characteristics, service provider characteristics,
and categorization to the interface and implementation description. The
UDDI entry carried this description.

I agree, we need to factor that in business description, service provider
description, and categorization description.

Should we add a layer over policy for 'service provider description' ?  I
was thinking that policy will usually apply to a service instance, just
like implementation and interface.

2. location discovery and interface discovery
I also think its VERY interesting to differentiatate between location
discovery and interface discovery. Thats an important point thats often
glossed over and forgotten.

How do we represent this? two arrows to the discovery agency?  Does that
mean there are also two publishes? interface and location? I think they are
parallel concepts.

Heather Kreger
Web Services Lead Architect
STSM, SWG Emerging Technology
kreger@us.ibm.com
919-543-3211 (t/l 441)  cell:919-496-9572


jones@research.att.com on 09/19/2002 01:39:45 PM

To:    distobj@acm.org, dorchard@bea.com, jones@research.att.com
cc:    Heather Kreger/Raleigh/IBM@IBMUS, www-ws-arch@w3.org
Subject:    RE: arch diagrams from the f2f



There is yet another issue muddled together in the description space.
We need to distinguish between describing the service provider and a
service being offered.  As in real life, I might want to select a
service not only on the basis of the service offered, but also on
parameters associated with the provider (number of years in business,
privacy policies, etc.).

Maybe the top of the logical description hierarchy should look like:
  service provider description
    (properties of providers,
     references to services they provide, ...)
  service description
    (properties of a service,
     backpointers to service providers??,
     references to service interface descriptions,
     service addresses)
  service interface description

In some schemes, given a service address, you can recover the other
information associated with the service.  To get the service address
in the first place, however, you might have to search based on
properties of the service.

In other schemes, the search might return a reference to a resource
that represents the entire service description (properties,
interface descriptions, service addresses, etc.).

In this modeling exercise, we should probably think hard about what
things we want to explicitly think of as (URI-referenceable) resources
by the way.

Mark Jones
AT&T

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 I think there are 2 issues that are being muddled together.  We probably
 need to separate them.

 There are at least 2 things that can be found from a "registry": The
 actual
 address of a resource, and the interface for interacting with it.  Mark
 Baker is pointing out that there is no need to publish the input interface
 for HTTP services, as HTTP defines the input interface.  For services that
 use SOAP, or other XML defined inputs, there may a need to discover the
 interface.  For example, a conversational web service might require a soap
 header with a conversation ID or a callback address.  This discovery could
 be through a variety of means - somebody mails me a copy of the spec, I
 discover the spec in UDDI registry, I de-ref a namespace URI, etc.

 I think we need to distinguish between discovering the address of the
 service, and the shape or interface of messages to and from the service.

 And BTW, I still don't think that HTTP is as generic as it appears.  To
 actually put information into the URL  and/or message, I as a human still
 have to do some work.  Like fill in a form.  And the only way I know what
 to
 put in the form is to "discover" the shape of the form from the web site.
 So in a form case, I get an address to the service, and the service
 provides
 the discovery mechanism and any new address for the actual service.
 Imagine
 url A accesses return the form, and the form says that it should be posted
 to url B.  Thus the discover/interact model for addresses and shapes is
 used
 by the web.

 Cheers,
 Dave

 > -----Original Message-----
 > From: www-ws-arch-request@w3.org [mailto:www-ws-arch-request@w3.org]On
 > Behalf Of Mark Baker
 > Sent: Thursday, September 19, 2002 9:37 AM
 > To: jones@research.att.com
 > Cc: distobj@acm.org; kreger@us.ibm.com; www-ws-arch@w3.org
 > Subject: Re: arch diagrams from the f2f
 >
 >
 >
 > On Thu, Sep 19, 2002 at 11:08:17AM -0400,
 > jones@research.att.com wrote:
 > > You somehow still have to come by the URI in the first
 > place, whether
 > > by work of mouth, google, etc.
 >
 > A previous GET ...
 >
 > >  Being spidered is a form of "publish".
 >
 > I'd say spidering was "interact" and "find".  "publish" would
 > be listing
 > your URI via POST at http://www.google.com/addurl.html
 >
 > > Using google is a form of "find".
 >
 > To search, sure.  But it's also "interact".
 >
 > I'm going to drop this now.  I'm trying hard to focus on the
 > architecture document and SOAP+WSDL, but I can't help but comment on
 > things I see being a concern later on.
 >
 > MB
 > --
 > Mark Baker, CTO, Idokorro Mobile (formerly Planetfred)
 > Ottawa, Ontario, CANADA.               distobj@acm.org
 > http://www.markbaker.ca        http://www.idokorro.com
 >
 >
Received on Thursday, 19 September 2002 22:02:16 GMT

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