Where it fits in the RA is still my question. In the example in his earlier email, Danny says
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.
If this example aligns with your meaning, then isn't my mind part of the opaque implementation? [The jokes are altogether too obvious so first answer the question and later we can collect the best Ken-related responses in a follow-on thread. :-) ]
Ken
On Aug 17, 2006, at 11:01 AM, Francis McCabe wrote:
The action being referred to in a service interaction is not really any private action. As you use a service to do something then you are performing an action. (There may be consequential events that follow that are internal.) That action has a point of action.
Note that with the action-at-a-distance analogy getting clarity on when and where the action is performed may be quite important. For example, if you send a message declaring that you have agreed to a contract, from the service provider's PoV, it is not until it 'groks' the message that it considers that you have actually agreed.
Frank
On Aug 17, 2006, at 7:24 AM, Ken Laskey wrote:
see below
At 09:18 AM 8/17/2006, Rex Brooks wrote:
I hope no one is surprised if I quibble with this particular definition, which comes close, in my opinion, but fall just short of the mark. I take exception with the choice of using the concept of force per se, though I do understand and agree with the requirement of making "action" transitive. I would apply a small bit of mental jiu jitsu on this definition, thus:
Action: the application of 'intent' to achieve an effect by an agent on an object.
Thus, the application of "intent" applies equally well to choosing to do "nothing" and allow inertia/momentum to achieve an effect,
but the application of nothing does not require an agent as the transferral entity if there is nothing to transfer, unless however you identify the agent as a way of establishing context for your intended nothing.
or to require action by some other agent to achieve, prevent or allow an effect. In the study of heuristics, one of the least well explored results is exactly this, the intentional refusal to act per se, which, I contend, constitutes a decision, which is, in and of itself, an action at a choice-point branching of a decision-tree.
BTW, this answers the last question below: Yes! and full responsibility or culpability applies. Needless to say, this is utterly critical to security. Choose not to apply a patch in time, and you are caught holding the hot potato if bad things happen to good systems.
So the follow-up question is: what can be identified as the poa while still maintaining the SOA principle of opacity of the implementation of services and their underlying capabilities?
Cheers,
Rex
At 7:55 AM -0400 8/17/06, Ken Laskey wrote:
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 <<mailto:>> 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
MITRE Corporation, M/S H305 phone: 703-983-7934
7515 Colshire Drive fax:
703-983-1379
McLean VA 22102-7508
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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
--
Rex Brooks
President, CEO
Starbourne Communications Design
GeoAddress: 1361-A Addison
Berkeley, CA 94702
Tel: 510-849-2309
--
---------------------------------------------------------------------------------
/ 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
smime.p7s
