Concepts in WSDM

[John DeCarlo <jdecarlo@mitre.org>]

Hello,

Perhaps instead of focusing first on the terminology, let us agree on 
the concepts.

William Vambenepe wrote:
> In our model, the only two real actors are the consumer (C) and the
> managed resource (MR). The manageability providers exists because it is
> the infrastructure that ensures that the MR gets the messages sent to
> it, but it doesn't receive messages of its own. It is just a conduit to
> get the messages routed to the MR, where the processing happens. So for
> all practical purposes I don't think it is helpful to mention the MP in
> these scenarios. The WSDL describes the manageability capabilities of
> the MR, not the MP.

This is an interesting statement, but also one that the WSDM TC has not 
agreed to.

The concepts that the WSDM TC started with and show up in all the 
documents is: all the WSDM message receipt and processing is done in the 
MP, which acts as an agent for the MR.  The MR, after all, is the entity 
being made manageable, not the entity providing manageability.

In fact, some proposals, like WSMF, specifically called out two 
entities:  a managed object and a managed resource - the first receiving 
SOAP messages, the second being a printer or other resource.  And the 
WSDM TC specifically rejected that notion, preferring instead having a 
Manageability Provider which could provide manageability for multiple IT 
resources.  The mechanism for telling the MP which IT resource you are 
managing has not yet been decided in detail by the WSDM TC.

However, the concept was also for Cs to be able to think about 
themselves managing MRs and not to have to think about themselves asking 
an MP to manage the MR on C's behalf.  (Which I believe is the essence 
of William's point, though I could be entirely wrong here.)

[Note that the MR and the MP can easily be one and the same, or the MP 
can be  implemented in seventy-three different locations.  Either way we 
go with these concepts, we need to be careful not to unduly constrain 
the locus of implementation.]

If we want to adopt William's approach, in the new world of 
WS-Addressing, WS-Resource Framework, etc., we can, but we need to all 
agree that it is useful to go this way.

And William's approach specifically precludes having a C talk directly 
to an MP.  So, WSDM could *not* implement a 
"TellMeAllTheMRsYouProvideManageabilityFor" operation.  And there may be 
valid reasons for WSDM to consider such operations or other 
manageability capabilities.


-- 

John DeCarlo, The MITRE Corporation, My Views Are My Own
email:      jdecarlo@mitre.org
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