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RE: arch diagrams from the f2f

From: Sedukhin, Igor <Igor.Sedukhin@ca.com>
Date: Fri, 20 Sep 2002 10:59:03 -0400
Message-ID: <87527035FDD42A428221FA578D4A9A5B77444C@usilms24.ca.com>
To: "Heather Kreger" <kreger@us.ibm.com>, <www-ws-arch@w3.org>, <jones@research.att.com>

1. probably falls in the area of SLA, BLA and other provisioning.
"consumer" needs the "service", "service" is hosted by the "provider".
Therefore I would not mix it into the baseline "consumer" -> "service"

2. I think that interface discovery is secondary. Once "consumer" found
a "service" with a business criteria and found where it is hosted, as a
second step, "consumer" would try to figure out how to talk to the
"service". Hence interface is secondary. There could be a few special
cases when "consumer" is looking for "services" given a particular
interface. In those cases the discovery happens in the same way (could
be P2P discovery as well). Then interfaces (a.k.a. contracts) are
matched with the equivalence rules.

-- Igor Sedukhin .. (igor.sedukhin@ca.com)
-- (631) 342-4325 .. 1 CA Plaza, Islandia, NY 11788

-----Original Message-----
From: Heather Kreger [mailto:kreger@us.ibm.com] 
Sent: Thursday, September 19, 2002 9:56 PM
To: www-ws-arch@w3.org; jones@research.att.com
Subject: RE: arch diagrams from the f2f

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
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

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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.


 > -----Original Message-----
 > From: www-ws-arch-request@w3.org
 > 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 Friday, 20 September 2002 10:59:34 UTC

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