Title: Message
Thanks Igor. In the text below, can we replace "both of the above are
currently out of scope of this specification" with "the specification of the
above is currently out of scope for this specification" (the difference being
that we won't normatively define them but we can talk about them, like we are
doing for services).
I cringe a bit at the choice of "metric" in the last paragraph as an
example, but since it's only an example...
Regards,
William
-----Original Message-----
From: Sedukhin, Igor S
[mailto:]
Sent: Wednesday, October 29, 2003
12:42 PM
To: WSDM TC
Subject: [wsdm] [Omod] concepts
diagram and words
Long time ago I promised to
provide words that go along with the MOWS concepts diagram. Here they are.
Also attached is the diagram aligned with UML 2.0.
<<MOWS
Concepts.png>>
So the words.
"
Management of Web services (MOWS) is a
particular case of Management using Web services (MUWS) in which a resource is
an element of a Web Services Architecture. The
Web services concepts, according to WSDL, are defined as follows. A service is
an aggregate of endpoints each offering the service at an address and
accessible according to a bidning. A service has a number of interfaces that
are realized by all of its endpoints. Each interface descibes a set of named
messages that could be exchanged and their format. Properly formatted messages
could be sent to an endpoint's address in a way prescribed by the binding. A
description (document, artifact) is composed of definitions of interfaces and
services. A description may contain both or either of the
definitions.
An IT resource may bear some
functional (e.g. business) responsibilities such as, for example, placement of
an order. That would constitute a functional capability with the distinct
semantics of placing an order. A functional resource is a composition of such
capabilties. An endpoint may provide access to the functional resource and in
that case would offer those capabilities. Such endpoint is called a functional
endpoint. To offer a capability an endpoint has to realize interfaces. An
interface that represents a functional capability is called a functional
interface. There is one to one match between capabilities and
interfaces.
The MUWS concepts are defined very
similarily to the functional concepts. There is a manageable resource that is
a resource composed of a number of manageability capabilities each represented
by a manageability interface.
Management of Web services starts
from an endpoint resource which therefore becomes manageable resource called
manageable endpoint. The reason the endpoint is the basis element is that (1)
anything behind an endpoint is a concrete implementation (e.g. an application
hosted in a container), and (2) anything that builds on endpoints is a logical
construct and therefore understaning of it has to be inferred. Both of the
above are currently out of scope of this specification.
Because manageable endpoint is a
manageable resource it is a composition of a number of manageability
capabilities. Some of the capabilities may be generic, defined in MUWS and
some may bear semantics specific to MOWS. For example, metrics available on
Web services endpoint resources only may be captured in a UML model called
EndpointMetrics which can be represented (rendered) into a WSDL interface
description defined in a "urn:wsdm:webservice:endpoint:manageability:metrics"
namespace. The UML model is an instance of the manageabilty capability concept
and the WSDL interface description is an instance of the manageability
interface concept.
"
-- Igor Sedukhin
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