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

[Ken Laskey <klaskey@mitre.org>]

At 12:10 PM 7/28/2005, Frank McCabe wrote:

[snip]

I think the following from Frank is a very good capture of the 
aspects of service we are trying to project.


>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.

A car is not a boundary between me and getting some place.  It is the 
capability to transport me along a continuous ground path (barring 
Hollywood stunts).  While the car has numerous interfaces, I'd be 
hard pressed to label its services in the context we are trying to describe.

We talked at the ftf about thin vs. thick boundaries as a metaphor 
for service.  In the limit, a zero-thickness boundary is a means of 
accessing a capability but provides none of its own.  While I'm not 
sure that we really have a zero-thickness boundary, I do believe the 
boundary to be very thin and most of its structure is pointing to 
other entities such as data models and policy statements.  These in 
turn are described elsewhere and their execution is done as a result 
of invoking a service but is not that service itself.

Ken

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Laskey                                                                \
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