Re: [wsdm] Terms being used in WSDM

[Tom Maguire <tmaguire@us.ibm.com>]

John DeCarlo <jdecarlo@mitre.org> wrote on 05/27/2004 02:43:01 PM:

> Hello,
>
> As was made painfully clear in today's call, the WSDM TC is using the
> term "endpoint" in at least two to four different ways.  And this is
> causing differences in perception of the Logical Model of MUWS.
>
> IMNSHO, this confusion is a "bad thing".

+1

> While I am not a good diagram creator or modifier, I believe we need to
> update the MUWS Logical Model to be clearer.
>
> Here is one proposal that will need to be shredded and reassembled
> before we can get agreement, but it is a place to start.
>
> In particular, I think that William and Heather would argue that there
> is no need any longer for the "manageability endpoint" in the WSDL
> sense.  They might argue that we only, perhaps, talk about the "thing
> pointed to by the Manageability EPR that accepts SOAP messages for
> exactly one Manageable Resource".  I can't say I understand the purpose,
> and personally find it too confusing.  Though it does simplify in the
> sense that you are always only talking to Manageable Resources, never to
> Manageability Providers (or their WSDL endpoints).
>
> Anyway, here is my proposal.
>
> PROPOSAL - When we use the term "endpoint", we only use it in the WSDL
> sense.  In all the WSDM specifications, including MUWS and MOWS.
>
> 1.  This means that we can leave all our diagrams the same, except that
> we have to add some things like EPRs or WS-Resources.
>
> 2.  When we use the term "EPR", we say it is a reference to a Manageable
> (Fred has a good point here that Managed is more correct once you get to
> sending SOAP messages) Resource.  And the content of the EPR is defined
> in WS Addressing, maybe clarified in WS-RF.

+1 to the notion.  -1 to "Managed":  managed is a verb; manageable is an
adjective.  Describing a noun/thing with a verb seems incorrect. In any
case
it seems like a pedantic argument since the definition of manageable is
"capable of being managed".

> 3.  Logically, to do something like GetResourceId, a Manageability
> Consumer sends a properly formatted WSDM SOAP message, which contains an
> EPR so that the Manageability Provider knows which Manageable Resource
> is being referred to, to the Manageability Endpoint specified in the
WSDL.

Not quite correct wrt "contains an EPR".  The SOAP message does not
contain an EPR.  The EPR is bound to message information headers of the
SOAP message.

>    3.a.  To remind people, this does not constrain the locus of
> implementation at all.
>    3.b.  The Manageability Endpoint (being a WSDL Endpoint) may have more

> than one Manageable Resource behind it.  The EPR helps out here one way
> or another according to best practices at the time.
>    3.c.  This begs the question of the singleton pattern.  Does it
require
> an EPR or not?  And if we support the *not* case, (which helps
> implementors that haven't gotten around to WS-RF, WS Addressing, EPRs,
> etc.) what are the implications?  [Note:  wiser heads than I have
> started this singleton discussion already.]
>
> 4.  The MUWS Concept Model should include EPRs.
>
>    4.a. One approach is to simply say there is a 1:1 mapping from
> Manageable Resource to EPR.  Then you have to mention that one "thing"
> being managed may have multiple Manageable Resources/EPRs.  This is what
> the current MUWS Concept model shows.  So we could add the EPR to the
> Concept Model as well.  In fact, doesn't the EPR allow the Manageability
>   Endpoint in the Concept model to provide access to exactly one
> Manageable Resource?

yes I think so.

>    4.b.  I don't think I like any other approaches, but will leave this
in
> here for a place holder.
>
>
> 5.  The MUWS Logical Model should address EPRs.
>
>    5.a.  One option is to say that the Manageability Consumer "accesses
> (and provides an EPR)" the Manageability Endpoint which "provides access
> to the Manageable Resource indicated by the EPR".
>


T o m   M a g u i r e

STSM, On Demand Architecture
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