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RE: [soa-forum] Re: Definitions of SOA

To: "Service-Oriented Architecture CoP" <soa-forum@xxxxxxxxxxxxxx>
From: "Metz Rebekah" <metz_rebekah@xxxxxxx>
Date: Mon, 8 May 2006 07:21:11 -0400
Message-id: <4765FEE3DE3FBF408F8A6D0B53F362DE017900A1@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>

Actually,  I used the word event in regards to the “what you do” portion of the RM.  I don’t know that this particular forum will understand your reference to Rob V.  However, I would disagree that the notion that a service is only a thing rather than also including a dynamic aspect didn’t gain traction.  Ultimately, we titled the two sections of the RM “Dynamics of Services”  and “About Services.”  One is about the stuff and the other is about what I refer to as a concept with the word event. 

 

Rebekah

 

Rebekah Metz

Associate

Booz Allen Hamilton

Voice:  (703) 377-1471

Fax:     (703) 902-3457

 


From: soa-forum-bounces@xxxxxxxxxxxxxx [mailto:soa-forum-bounces@xxxxxxxxxxxxxx] On Behalf Of Ken Laskey
Sent: Monday, May 08, 2006 7:14 AM
To: Service-Oriented Architecture CoP
Subject: Re: [soa-forum] Re: Definitions of SOA

 

talk about deja vu all over again :-)

 

I got confused at one point with who wrote what.  Did you introduce the service as event?  We incorporated "service duality" through one section on dynamics and then the "thing" part in About Services  but the concept of service as event, although a favorite of Rob V, never gained traction with the TC.

 

heading to SF later today to hopefully put on finishing touches.

 

Ken

 

On May 8, 2006, at 1:27 AM, Metz Rebekah wrote:



A few contextual comments and questions inline.  I typed these originally on Friday night before the thread of conversation spun out with some other members of the SOA-RM on this mailing list.  However, I think my comments below still apply.

 

Rebekah

 

Rebekah Metz

Associate

Booz Allen Hamilton

Voice:  (703) 377-1471

Fax:     (703) 902-3457

 

 

-----Original Message-----
From: soa-forum-bounces@xxxxxxxxxxxxxx [mailto:soa-forum-bounces@xxxxxxxxxxxxxx] On Behalf Of Andras Szakal
Sent: Friday, May 05, 2006 9:50 AM
To: Chris Harding
Cc: Service-Oriented Architecture CoP; soa@xxxxxxxxxxxxx
Subject: [soa-forum] Re: Definitions of SOA

 

Team,

 

I offer this additional chart which depicts the outcome of our discussion

last week. I am still working the chart but it's a decent start. We agreed

that SOA is actually only one aspect of this very interesting industry

initiative that needs our focus.

 

<RLM>  Although I like the concepts that you’ve related to the notion of services and SOA, I have a concern that SOA seems to be considered only as a technology layer concept of a larger concept called SOA.  I would challenge the group to realize instead that SOA is about the alignment of IT with business.  Intuitively, this concept spans the three layers in the first slide. 

 

As part of the SOA RM out of OASIS, we initially started down this same path.  In fact, during early drafts of the RM, several members of the TC contemplated renaming the specification to “Service Reference Model.”  In addition, we spent a significant amount of time working to a description of SOA that spans these three layers presented - because they are synergistic.  (Note that within the reference model we don’t directly discuss technologies which are left for Reference Architectures and Implementations). 

 

I think we need to focus on service orientation as a superset of the SOA

discussion. In fact one could argue that service orientation may be

implemented by a combination of architectural styles and not just SOA/web

services.

I’d be interested in hearing about what other architectural styles fit the bill.

 

(See attached file: Service_Orientation_Def_v1.ppt)

 

<Stepping onto my soapbox>

The notion that a service is a “thing” which is separate from a capability that is served is incorrect.  A service is an event.  It is not separate from a capability.  It is the performance of that capability by some entity (service provider) for some other entity (service consumer).  Although it is easy to think about the concept of service in terms of ‘things’; in actuality, this concept unifies both active and thing.  In the same vein, it is a red herring to think about SOA as technology only. 

 

In Slide #2, the discussion of service orientation maps nicely to the treatment of needs and capabilities as part of the SOA Reference Model.  The difference is that this definition seems to treat service orientation separately from the core definition of SOA.  Instead, brining together needs and capabilities is of the essence in SOA, an integral part. 

 

The definition of service speaks of a black box.  With this definition, I would ask what is the role of a service description?  Does the existence of a service interface, and the inputs/outputs with which service interactions occur part of the black box?

 

I don’t understand why the final two bullets, namely “Requires strong governance of service representation and implementation” and “Requires a ‘Litmus Test’, which determined a ‘good services’ are part of the definition?  Who decides “good” vs. “bad” services? 

 

Rebekah

 

 

Regards,

 

Andras

 

 

 

Andras Robert Szakal

Chief Architect IBM Federal Software Group

Distinguished Engineer & Senior Certified IT Architect

Member Open Group Board of Directors

Tie Line: 930-9215

External Line: 202-595-1678

text message: andras1@xxxxxxxxx

email: aszakal@xxxxxxxxxx

 

 

                                                                           

             Chris Harding                                                

             <c.harding@opengr                                            

             oup.org>                                                   To

                                       Service-Oriented Architecture CoP  

             05/05/2006 08:31          <soa-forum@xxxxxxxxxxxxxx>,        

             AM                        "'Service-Oriented Architecture    

                                       CoP'" <soa-forum@xxxxxxxxxxxxxx>   

                                                                        cc

                                       soa@xxxxxxxxxxxxx                  

                                                                   Subject

                                       Definitions of SOA                 

                                                                          

                                                                          

                                                                           

                                                                          

                                                                          

                                                                           

 

 

 

 

Hi -

 

As a further update, here is the definition of SOA that was presented at

The Open Group conference last week (and which we have shared with the

OMG).

 

SOA is an architectural style that supports service orientation

 

•Service orientation

A way of a way of thinking in terms of services and service based

development and the outcomes that services bring

 

•Service

A logical representation of a repeatable business activity that has a

specified outcome (e.g., check customer credit; provide weather data,

consolidate drilling reports), is self-contained and maybe composed of

other Services. It is a black box to consumers of the Service

 

•Architectural Style

The combination of distinctive features in which Enterprise Architecture is

done, or expressed

 

•The SOA Architectural style’s distinctive features:

  – Based on the design of the services comprising an enterprise’s

     (or inter-enterprise) business processes. Services mirror real-world

     business activity

  – Service representation utilizes business descriptions. Service

     representation requires providing its context (including business

     process, goal, rule, policy, service interface and service component)

     and service orchestration to implement service

  – Has unique requirements on infrastructure. Implementations are

     recommended to use open standards, realize interoperability and

     location transparency.

  – Implementations are environment specific, they are constrained or

    enabled by context and must be described within their context.

  – Requires strong governance of service representation and implementation

  – Requires a “Litmus Test", which determined a “good service”

 

At 20:31 04/05/2006, Cory Casanave wrote:

 

      As an update from the OMG meeting last week, the SOA SIG adopted the

      following definition of SOA;

 

 

 

      Service Oriented Architecture is an architectural style for a

      community of providers and consumers of services to achieve mutual

      value, that:

            Allows participants in the communities to work together with

            minimal co-dependence or technology dependence

            Specifies the contracts to which organizations, people and

            technologies must adhere in order to participate in the

            community

            Provides for business value and business processes to be

            realized by the community

            Allows for a variety of technology to be used to facilitate

            interactions within the community

 

 

 

 

 

      The corresponding definition of service has not yet been finalized

      but the sense of the group is that there would be both a

      business/domain centric notion of service as well as an interaction

      focused definition.

 

 

 

      In both cases this seems to fit well with the notion of SOA that is

      evolving in this group and in the SOA Demo.

 

 

 

      Regards,

 

      Cory Casanave

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Regards,

 

Chris

+++++

 

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