[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: RE: [soa-rm] Definition(s) of "service"
> -----Original Message----- > From: Frank McCabe [mailto:frank.mccabe@us.fujitsu.com] > Sent: Monday, August 08, 2005 12:10 PM > To: Ken Laskey > Cc: soa-rm@lists.oasis-open.org > Subject: Re: [soa-rm] Definition(s) of "service" > > This is going in a weird direction. > I believed that there was significant consensus that the > notion of service that we are interested in *is* the > interface/boundary/offering. > > The capability behind the service -- that which makes the > service possible -- is private and out of bounds. That > capability is, by the way, best described using agent terminology. Respectful non-concur. IMHO, the service *is* the capability, and the service *has* an interface through which interaction with that capability may be possible. Joe Joseph Chiusano Booz Allen Hamilton O: 703-902-6923 C: 202-251-0731 Visit us online@ http://www.boozallen.com > Frank > > On Aug 8, 2005, at 8:50 AM, Ken Laskey wrote: > > > This is good because it highlights the bits of confusion we have to > > explain our way around. > > > > The user interface is the facade through which the user > interacts with > > a service (i.e. inputting information/requests, viewing > > results) but there may be delivery capabilities that are invoked > > through relevant services and the delivery capabilities are the > > mechanisms through which results are packaged and sent to the > > requester/consumer. For example, if I make a request for > an image and > > as part of that request, information about my connectivity is > > provided, logic (capability) can be executed (possibly > invoked through > > a service) to decide which delivery mechanism is most appropriate > > (e.g. high res or low res, what kind of compression, ...). > > > > Ken > > > > At 11:18 AM 8/8/2005, Michael Stiefel wrote: > > > >> Actually, I think two things are being confused here. > >> > >> There is one service being used by several different > applications. > >> The user interface (i.e. the actually delivery mechanism) > is not part > >> of the service, or strictly speaking part of the SOA. > >> > >> Michael > >> > >> At 10:43 AM 8/8/2005, Ken Laskey wrote: > >> > >>> I'd have to think about this further but in general I > would say yes. > >>> The underlying capability is making pizza and offering > the product > >>> for sale. The mechanisms for accessing the capability are in > >>> person, by phone, online. Note, the capability existed > before there > >>> was online ordering and this is just another > >>> mechanism to access a capability that already existed. > >>> Interestingly from an orchestration/choreography sense, > the delivery > >>> of the pizza (in person pickup, delivery service from > pizza place, > >>> third-party delivery (e.g. Takeout Taxi around > >>> here)) constitutes another set of capabilities that can > have service > >>> interfaces and can be combined in response to invoking > the ordering > >>> service. All of these can be used for delivery of things > other than > >>> pizza (even the pizza place might also deliver sandwiches). > >>> > >>> I think part of the confusion is that a *physical* > delivery service > >>> is a millennia-old, longstanding capability that has > nothing to do > >>> with SOA and is *not* the service in the SOA sense but it uses a > >>> different aspect of the S word. > >>> > >>> Ken > >>> > >>> At 07:11 PM 8/7/2005, joe@pantella.net wrote: > >>> > >>>> Does this imply that if I order a pizza online vs. order a pizza > >>>> over the phone vs. order a pizza by walking into the store, that > >>>> these are all separate services? > >>>> > >>>> --JJP > >>>> > >>>> -----Original Message----- > >>>> From: Ken Laskey [mailto:klaskey@mitre.org] > >>>> Sent: Thursday, August 04, 2005 12:35 PM > >>>> To: soa-rm@lists.oasis-open.org > >>>> Subject: RE: [soa-rm] Definition(s) of "service" > >>>> > >>>> > >>>> This gets back to the previous discussion when we talked about > >>>> resources, i.e to what extent the service is the mechanism to > >>>> access (possibly coordinate) capability vs. when is it > considered > >>>> the capability itself. > >>>> > >>>> I think any consideration of the service as the > capability/resource > >>>> should be very limited. > >>>> > >>>> Ken > >>>> > >>>> At 11:07 AM 8/4/2005, Chiusano Joseph wrote: > >>>> > > -----Original Message----- > >>>> > > From: Ken Laskey [mailto:klaskey@mitre.org] > >>>> > > Sent: Thursday, August 04, 2005 11:04 AM > >>>> > > To: Chiusano Joseph; soa-rm@lists.oasis-open.org > >>>> > > Subject: RE: [soa-rm] Definition(s) of "service" > >>>> > > > >>>> > > 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. > >>>> > > >>>> >Agree - and I should clarify that I was merely saying that a > >>>> service > >>>> >provides capabilities (in general). Combining a > capability here, a > >>>> >capability there, here a capability, there a capability, > >>>> everywhere a > >>>> >capability (oops sorry - that's the EIEIO song), we > have composite > >>>> >capabilities. > >>>> > > >>>> >Joe > >>>> > > >>>> >Joseph Chiusano > >>>> >Booz Allen Hamilton > >>>> >O: 703-902-6923 > >>>> >C: 202-251-0731 > >>>> >Visit us online@ http://www.boozallen.com > >>>> > > >>>> > > 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 > >>>> > > / > >>>> > > > >>>> > > > -------------------------------------------------------------- > >>>> > > -------------------- > >>>> > > > >>>> > > > >>>> > > > >>>> > > > >>>> > >>>> -- > >>>> > ------------------------------------------------------------------- > >>>> -------------- > >>>> / 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 / > >>> > -------------------------------------------------------------------- > >>> -------------- > >>> > >> > >> > >> > > > > -- > > > > > ---------------------------------------------------------------------- > > ----------- > > / Ken > > Laskey > > > \ > > | MITRE Corporation, M/S H305 phone: 703-983-7934 | > > | 7515 Colshire Drive fax: > > 703-983-1379 | > > \ McLean VA > > 22102-7508 / > > > > > ---------------------------------------------------------------------- > > ------------ > > > > > > > >
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]