Re: [soa-rm-ra] point of action

[Ken Laskey <klaskey@mitre.org>]

Some comments from Frank that didn't get back to the list:

Ken:

�The POA *is* the action as it is applied.

�If the service is the glove, the POA is the iron fist:)

�Different people have different definitions of action, (try define:action in google). None of these definitions is all that satisfactory to me.

�My definition is adapted from John Sowa:

Action: the application of force by an agent on an object with the intention of achieving an effect.

�I.e., its a kind of event. The POA is a characterization of that event. (One reason I like this definition is that is includes all human actions but excludes rocks rolling down the hill hitting other rocks.)

�The service interface is the characterization of what it means to perform an action. It is not the action itself though.

�Hope that this throws a little light on the matter.

Frank

Per Danny's response, I think he caught my question well with the final line of his response below:

One question

we can ask is can we identify a point of action

meaningful to the reference architecture that would

not have a service interface?

Ken

On Aug 17, 2006, at 1:55 AM, Danny Thornton wrote:

To draw another analogy for the point of action, I

know your mind will be the point of action for

processing this e-mail as you read the e-mail.� The

e-mail address and the english language is like a

service interface.�

The SOA has many points of action, each point of

action potentially affecting many other points of

action.� We can identify points of action in a SOA

relevant to the reference architecture.� One question

we can ask is can we identify a point of action

meaningful to the reference architecture that would

not have a service interface?

Danny

--- Ken Laskey <klaskey@mitre.org> wrote:

The following are from my notes at the ftf

Point of Action (poa)

- � � � Frank: anchoring mechanism for numerous

things, e.g. policy �

enforcement, evaluating needs & capabilities

- � � � Ken: how does poa relate to service

interface?� Frank: �

service interface includes actions you can perform;

each instance of �

use consists of performing action; actual action is

poa; interface �

vs. poa is class vs. instance relationship; the

physical action is �

the point of action

- � � � [Ken] Given a policy is a desire of one

participant and an �

agreement as part of the execution context for

participants to abide �

by that policy (i.e. the other participant(s) agree

to make that �

policy theirs), the policy enforcement point becomes

the point of �

action for enforcing the agreed-upon policy.

- � � � [Frank alternative] A policy is a constraint

that represents �

the desire of a participant. A contract is a

constraint that �

represents the agreed desires of two or more

participants. A [policy] �

enforcement point is the point of action for

enforcing constraints �

that represent either policies or contracts.

I've reread this and am still having problems

differentiating between �

service interface and point of action.� It appears

that poa is more �

general because it is the location to which a user

would send a �

command for action.� If the receiver is a service,

then the poa would �

seem to be the service interface.� In the policy

example, if the �

enforcement mechanism is accessed through a service,

the PEP could be �

said to have a service interface.

I still seem to be missing something.

Ken

---

Ken Laskey

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---

Ken Laskey

MITRE Corporation, M/S H305� � �phone:� 703-983-7934

7515 Colshire Drive� �� �� �� �� �� �� �� �fax:� � �� �703-983-1379

McLean VA 22102-7508