Terms being used in WSDM

[John DeCarlo <jdecarlo@mitre.org>]

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".

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.

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.
	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?

	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".

-- 

John DeCarlo, The MITRE Corporation, My Views Are My Own
email:      jdecarlo@mitre.org
voice:      703-883-7116
fax:        703-883-3383
DISA cube:  703-882-0593