Re: [soa-rm-ra] Groups - Modification of Policy_Contract_Business diagram (OASIS_Policy-Contract_Diagram.JPG) uploaded

[Danny Thornton <danny_thornton2@yahoo.com>]

Michael,

Comments on the diagram:

Defining policies and contracts as having a
composition of executable statements is one level of
detail less abstract than the intended abstraction
level of the intro section for Policies and Contracts.
 For IT mechanisms, I would prefer measurable rules or
measurable statements to executable statements where
the measurable rules are derived from policy/contract
propositions.  However, not all policy/contract
propositions in the business realm translate into
measurable statements that can be handled by the IT
realm.

There could be many types of SLAs and there could many
attributes for Contracts.  The policies and contracts
section does not try to list all of these
possibilities, it is describing the common
abstractions of policies and contracts and how that
flows into common IT mechanisms that handle policies
and contracts.  Expanding on a contract, the
discussion of SLAs for example, is a topic for the
Service Description section.

The OASIS reference model states that "A policy
represents some contra int or condition on the use,
deployment or description of an owned entity as
defined by any participant."  It states that "A
contract, on the other hand, represents an agreement
by two or more parties."  

I do not interpret the OASIS SOA RM to mean what
you've defined in statement 2, "a Policy can be
applied to the service via a Contract only. The most
primitive form of a Contract is the Policy. This
constitutes an implicit Contract."

During the 3-21-2007 telecon on policies and
contracts, the committee was in general agreement that
Contract does not equate to Policy. The relationship
of contract to policy must hold true in the business
realm as well as the IT realm.  To do business, a
person signs contracts, they generally do not sign
policies.  There is legal recourse for breaking a
business contract but there may not be any legal
recourse for not abiding by a policy.  A person may
have to abide by policies that are not part of a
contract.  If someone enters a store without shoes and
a shirt, they may be breaking the store's "shoes and
shirt required" policy, but they would not be breaking
a contract because they never agreed/signed a contract
with the store.    

I could go on and on about the misuse of the term
contract in the IT realm when referring to things like
interface, IDLs, or WSDLs but I don't think that would
be productive.

Danny
 
--- michael.poulin@uk.fid-intl.com wrote:

> The document named Modification of
> Policy_Contract_Business diagram
> (OASIS_Policy-Contract_Diagram.JPG) has been
> submitted by Mr. Michael
> Poulin to the SOA-RM Reference Architecture
> Subcommittee document
> repository.
> 
> Document Description:
> A modification of Policy_Contract_Business diagram
> for SOA RA SC.
> 
> Comments:
> 1) a Contract os an optional element of the picture
> as well as a Policy.
> Contract may be explicit or implicit.
> 
> 2) a Policy can exist independently from a Contract,
> however a Policy can
> be applied to the service via a Contract only. The
> most primitive form of a
> Contract is the Policy. This constitutes an implicit
> Contract.
> 
> 3) Contract can include SLA and Service Descriptor
> in addition to the
> Contract specific attributes. The Service Descriptor
> represents the subject
> of the Contract. 
> 
> 4) One Contract may refer to only one Service
> referenced by the Service
> Descriptor
> 
> 5)A Contract, as well as a Policy, consists of
> expressions that can be
> executed. That is, they can be measured. The methods
> of execution may vary.
> An Executable Expression is the fact the
> participants have agreed upon, it
> is not a proposition (which may not be accepted)
> 
> 6)Every Executable Expression may be implemented in
> a form of either
> Assertion or Commitment (i.e. promise of one or both
> Participants to
> perform certain actions under given Contract). If a
> Contract is in implicit
> form, i.e. expressed as a Policy only, the
> Executable Expression may be
> implemented as an Assertion only. The Assertion and
> Commitment may have
> different sets of related Attributes.
> 
> 7) A Contract always includes two Participants while
> a Policy may be
> applied to one or many participants of the service
> communication. The
> Policy is not directly associated with any
> particular participant.
> 
> 8) a Participant is implemented as a Stakeholder
> which gets concrete via
> Social Structure of the Participant. Thus, the
> Assertion and Commitment
> deal with the Stakeholder rather than with an
> abstract Participant.
> 
> 
> View Document Details:
>
http://www.oasis-open.org/apps/org/workgroup/soa-rm-ra/document.php?document_id=23854
> 
> Download Document:  
>
http://www.oasis-open.org/apps/org/workgroup/soa-rm-ra/download.php/23854/OASIS_Policy-Contract_Diagram.JPG
> 
> 
> PLEASE NOTE:  If the above links do not work for
> you, your email application
> may be breaking the link into two pieces.  You may
> be able to copy and paste
> the entire link address into the address field of
> your web browser.
> 
> -OASIS Open Administration
> 


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