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Overhauling the discovery part of the architecture document

From: Hugo Haas <hugo@w3.org>
Date: Thu, 9 Jan 2003 13:19:23 +0100
To: www-ws-arch@w3.org
Message-ID: <20030109121923.GE2298@w3.org>

Hi all.

I am concerned that the discovery part[2] of the architecture document
is written from a technology point of view, rather than from the point
of view of exposing a problem, describing the characteristics of the
problem, and then starting to talk about how existing technologies
propose solutions to the problem, or parts of it.

I think that it is because this part has been, to the extreme with all
the detailed description of UDDI and the mention of WSIL, based on
exposing existing technologies, without concentrating on what problem
they are solving. I basically think that we are presenting a solution
to an undefined, or under-defined, problem, and that doesn't seem like
a sound approach to me, and gives us a biased view of the situation.

I would therefore like to first define the problem and, see how it can
be addressed, and how existing technologies cover the proposed
solutions.

Also, I think that the way I see things will make us make progress
(hopefully) on what a role (in particular "Discovery agency") is.

The current diagram has IMO a couple of issues:

Issue 1: who publishes the description?

I don't think it must be reserved to the service provider. For
example, if I am a consumer and I want to decide what the service
should look like, and the provider had better agree if it wants to get
the insane amount of money I am offering for it.

The current model does not allow such a scenario to happen, which
looks like a serious limitation.
  
One key point is that both actors actually need to agree on a service
description, and then the service description could be published by
either, or even both.

Issue 2: The "Find" action.

If a "Discovery agency" is used, one (the requestor or the service)
may *get* a description from it. Find implies that the agency is
searchable, which may not always be necessary (e.g. a single
description on a sheet of paper).

I think that there are three things to do in order to address those
problems:
- have a diagram in addition to the triangle one, showing that what is
  needed between the provider and the requestor is an *agreement* of
  how to proceed.
- modify the triangle diagram to:
  + allow for the information flow to go both ways.
  + not imply that the agency is searchable.
- rewrite the discovery section in abstract terms:
  + what are we agreeing on? syntax, semantics, etc.
  + what needs to be achieved? common view of what is going to happen.
  + how is it going to be achieved?
    . via a description agreed on.
    . the description needs to reach both actors.
    . etc.

Only at that point can we start talking about documents, Web
resources, transfer of representation of those resources, potential
indexing and research, etc.

Comments?

Regards,

Hugo

  1. http://www.w3.org/TR/2002/WD-ws-arch-20021114/#basic
  2. http://www.w3.org/TR/2002/WD-ws-arch-20021114/#discstack
-- 
Hugo Haas - W3C
mailto:hugo@w3.org - http://www.w3.org/People/Hugo/
Received on Thursday, 9 January 2003 07:19:26 GMT

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