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Subject: RE: [soa-rm-editors] alternate description of execution context
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What are the general thoughts on this
replacement? Duane ******************************* From: Ken Laskey
[mailto:klaskey@mitre.org] In reading v10, I don't believe the current discussion of execution
context is clear and being this is something new we are trying to explain, I
offer below some alternate words, especially for lines 623-630. I figured
I'd run it by the editors first to see if we could come to a consensus among
those who have previously discussed the concept rather than starting the
discussion in a room of people with little if any context. <suggested> The execution context of a service interaction
is a set of infrastructure elements, process entities and policy assertions and
a collection of agreements and coordination of conditions, the result of which
enables service consumers and service providers to establish the appropriateness
and explicit mechanisms for the invocation of a service. As noted in
Section 3.2.2, a service description includes how to use a service, what
conditions must be satisfied to use the service, and what effects will result
from using the service. However, the service consumer has a corresponding
description of the needs which are to be satisfied, the conditions under which
the consumer is willing to have a service satisfy those needs, and expectations
on the effects of using the service. Visibility alerts the service
consumer and service provider that an interaction may have value, but a
matching of consumer and provider descriptions, policies, and constraints is
necessary for service use to be desired, allowed, and enabled to
occur. The consumer and provider
can be envisioned as separate places on a map and, for a service to actually be
invoked, a path must be established between those two places. This path
is the execution context. As with a path between places, it can be a
temporary connection (e.g. a tenuous footbridge of a very limited agreement) or
a well-defined coordination (e.g. a super highway) that can be easily reused in
the future. Note, there may be third parties, for example, government regulators,
who set some of the conditions for the execution context, but this merely
increases the conditions and constraints needing to be coordinated and may
require additional information exchange to complete the execution context. The execution context is central to many aspects of a service
interaction. It defines, for example, the decision point for any policy
enforcement relating to the service interaction. Note that a
policy decision point is not necessarily the same as an enforcement point:
an execution context is not by itself something that lends itself to
enforcement. On the other hand, any enforcement mechanism of a policy is
likely to take into account the particulars of the actual service
interaction. The execution context is likely distinct for a specific service and
prospective consumer. Different instances of the same service – denoting
interactions between a given service provider and different
service consumers for example – are distinguished by virtue of the fact
that their execution contexts are different. Finally, the execution context is also the context in which the
interpretation of data that is exchanged takes place – it is where the
symbol grounding happens as it were. A particular string has a particular
meaning in a service interaction in a particular context – the execution
context. </suggested> Note, this is just the result of my reading and I did not check to see
whether others have submitted issues on this section. Ken --- Ken Laskey MITRE Corporation,
M/S H305 phone: 703-983-7934
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