Re: [soa-rm] Definition(s) of "service"

[John Harby <jharby@gmail.com>]

Yeah, exactly. That's why I'm not sure about where Ken was saying:

"Somehow saying service *provides* capabilities  misses the SOA
motivation to provide an effective way to bring together
the parts I need to solve a problem.  Integration is often of
disparate parts that
exist for their own purposes..."

I think the service itself should be as agnostic as possible of any
integration. Otherwise
we end up with many potentially unnecessary complex dependencies.

On 8/4/05, Chiusano Joseph <chiusano_joseph@bah.com> wrote:
> > -----Original Message-----
> > From: John Harby [mailto:jharby@gmail.com]
> > Sent: Thursday, August 04, 2005 11:47 AM
> > To: soa-rm@lists.oasis-open.org
> > Subject: Re: [soa-rm] Definition(s) of "service"
> >
> > But what responsibility should the service have in this
> > "bringing together of the parts"?
> 
> For our RM, none. And by "service", I believe you mean a composite
> service or coordinator in orhestration terms, both of which are too
> concrete for our RM.
> 
> Joe
> 
> Joseph Chiusano
> Booz Allen Hamilton
> O: 703-902-6923
> C: 202-251-0731
> Visit us online@ http://www.boozallen.com
> 
> > I would be very concerned about levying too much
> > responsibility on the service for the integration.
> >
> > On 8/4/05, Ken Laskey <klaskey@mitre.org> wrote:
> > > Somehow saying service *provides* capabilities  misses the SOA
> > > motivation to provide an effective way to bring together
> > the parts I
> > > need to solve a problem.  Integration is often of disparate
> > parts that
> > > exist for their own purposes.  Service can help coordinate but the
> > > challenge is to make use of the tools/resources/capabilities that
> > > already exist, not to create new stovepipes.  Saying the service
> > > provides all this is a tempting simplification but I fear it will
> > > trivialize  the concepts most in need of clarification.
> > >
> > > Ken
> > >
> > > At 10:35 AM 8/4/2005, Chiusano Joseph wrote:
> > > > > -----Original Message-----
> > > > > From: Ken Laskey [mailto:klaskey@mitre.org]
> > > > > Sent: Thursday, August 04, 2005 10:18 AM
> > > > > To: soa-rm@lists.oasis-open.org
> > > > > Subject: RE: [soa-rm] Definition(s) of "service"
> > > > >
> > > > > I'd still like to emphasize service as the access to
> > capabilities
> > > > > for which there are extra-service motivations for their
> > existence
> > > > > and requirements for use of the capabilities that must be
> > > > > navigated by the service.  Thus,
> > > > >
> > > > > "A service is a mechanism to enable access to a set of
> > > > > capabilities,
> > > >
> > > >I would say that access control mechanisms enable such access, and
> > > >that the service *provides* the capabilities. Note: Use of
> > "access control"
> > > >is too concrete for our RM - I stated it only to
> > illustrate the point.
> > > >
> > > >Joe
> > > >
> > > >Joseph Chiusano
> > > >Booz Allen Hamilton
> > > >O: 703-902-6923
> > > >C: 202-251-0731
> > > >Visit us online@ http://www.boozallen.com
> > > >
> > > > > where the access is provided using a prescribed
> > interface and is
> > > > > exercised consistent with constraints and policies as
> > specified by
> > > > > the service description."
> > > > >
> > > > > Ken
> > > > >
> > > > > At 11:15 PM 8/3/2005, joe@pantella.net wrote:
> > > > >
> > > > > >Just trying to sort through this; some common themes
> > that seem to
> > > > > >be
> > > > > >acceptable:
> > > > > >
> > > > > >A service provides capabilities.
> > > > > >A service is accessible. (If this is true, then
> > service cannot be
> > > > > >a
> > > > > >verb.) A service has an interface. (If this is true, then a
> > > > > service has
> > > > > >a boundary.) A service interface is prescribed. (Then a
> > > > > service and its
> > > > > >interface are distinct, and the interface has
> > associated rules.
> > > > > >I'm not sure this is true, the interface may describe
> > the rules,
> > > > > but Im not
> > > > > >sure it has rules.  In fact, I'm inclined to suggest that
> > > > > the interface
> > > > > >defines the rules for accessing the service.  Which
> > would lead me
> > > > > >to suggest that the service interface is more than a
> > > > > specification of the
> > > > > >data model, but also of the policies associated with the
> > > > > >service.) A service is a set of behaviors.  (Not sure I'm on
> > > > > >board with this, something about behaviors doesn't sit well.)
> > > > > >
> > > > > >Given this, perhaps something like:
> > > > > >
> > > > > >"A service is a bounded set of capabilities that are
> > > > > accessible through
> > > > > >a prescribed interface."
> > > > > >
> > > > > >
> > > > > >-- JJP
> > > > > >
> > > > > >P.S. I think this definition might just be flexible enough
> > > > > to navigate
> > > > > >the service offer/contract discussion also.
> > > > > >
> > > > > >
> > > > > >-----Original Message-----
> > > > > >From: Schuldt, Ron L [mailto:ron.l.schuldt@lmco.com]
> > > > > >Sent: Thursday, July 28, 2005 12:32 PM
> > > > > >To: Frank McCabe; SOA-RM
> > > > > >Subject: RE: [soa-rm] Definition(s) of "service"
> > > > > >
> > > > > >
> > > > > >Frank,
> > > > > >
> > > > > >While I believe that the previously proposed definition is
> > > > > sufficient,
> > > > > >I offer the following as a compromise. Hopefully, the
> > notion of
> > > > > >"capabilities" addresses your issue of needing to get
> > things done.
> > > > > >
> > > > > >"A service is a set of behaviors to provide capabilities
> > > > > accessible via
> > > > > >a prescribed interface."
> > > > > >
> > > > > >Ron
> > > > > >
> > > > > >
> > > > > >-----Original Message-----
> > > > > >From: Frank McCabe [mailto:frank.mccabe@us.fujitsu.com]
> > > > > >Sent: Thursday, July 28, 2005 10:10 AM
> > > > > >To: SOA-RM
> > > > > >Subject: Re: [soa-rm] Definition(s) of "service"
> > > > > >
> > > > > >
> > > > > >I hesitate to spoil this party ... but I'm going to :)
> > > > > >
> > > > > >1. There is a distinction between action and result. (Just ask
> > > > > >any
> > > > > >roboticist) Behaviour sounds a child misbehaving with no
> > > > > >discernible effect. Computer Scientists have a
> > tendency to focus
> > > > > >on the purely technical aspects of their work: bytes shuffling
> > > > > >around at random within hopefully enormous memories.
> > > > > >2. Also, we have to bear in mind that nobody invests
> > > > > millions of $s (or
> > > > > >even 100's of them) in systems that contemplate their navels
> > > > > or have no
> > > > > >business payoff. I think that we have to directly address the
> > > > > >reason that services are deployed.
> > > > > >3. One of the movitating best practice aspects of SOAs is
> > > > > that clarity
> > > > > >and 'separation' between the providers of services and the
> > > > > consumers of
> > > > > >services leads to more scalable and robust architectures.
> > > > > >
> > > > > >All of the above is fuzzy language; but, at the same time,
> > > > > "A service
> > > > > >is a set of behaviors accessible via a prescribed interface."
> > > > > >sounds a lot like bureauspeak.
> > > > > >
> > > > > >I believe that there is strong consensus on the following
> > > > > >characteristics:
> > > > > >a. The concept of service is 'at the boundary' between service
> > > > > >providers and consumers.
> > > > > >b. The service is 'there' to get things done; but doesn't
> > > > > itself denote
> > > > > >the engine that performs the tasks.
> > > > > >c. There is a reason for using a service.
> > > > > >d. There is a lot of extra metalogical information about
> > > > > services that
> > > > > >make it possible for third parties to develop partners
> > for services.
> > > > > >
> > > > > >I, for one, would prefer a strongly anglo-saxon
> > phrasing of the
> > > > > >definition of service that speaks to these points.
> > > > > >
> > > > > >Frank
> > > > > >ti
> > > > >
> > > > > --
> > > > >
> > > > > --------------------------------------------------------------
> > > > > -------------------
> > > > >    /   Ken
> > > > > Laskey
> > > > >         \
> > > > >   |    MITRE Corporation, M/S H305    phone:  703-983-7934   |
> > > > >   |    7515 Colshire Drive                    fax:
> > > > > 703-983-1379   |
> > > > >    \   McLean VA 22102-7508
> > > > >            /
> > > > >
> > > > > --------------------------------------------------------------
> > > > > --------------------
> > > > >
> > > > >
> > > > >
> > > > >
> > >
> > > --
> > >
> > --------------------------------------------------------------
> > -------------------
> > >    /   Ken
> > > Laskey
> >           \
> > >   |    MITRE Corporation, M/S H305    phone:  703-983-7934   |
> > >   |    7515 Colshire Drive                    fax:
> > 703-983-1379   |
> > >    \   McLean VA 22102-7508
> >              /
> > >
> > >
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