After reading this discussion the meaning of POA is not clear to me at all.
Perhaps future discussions will make its meaning and usefulness clearer.
Michael
At 12:06 PM 8/17/2006, Ken Laskey wrote:
>OK for now. Hopefully the use of poa in the RA will clarify things or
>this is going to be a bear to write up for our audience.
>
>Ken
>
>At 11:37 AM 8/17/2006, Francis McCabe wrote:
>>The POA concept is a general concept that is not limited to services.
>>So, perhaps, that is what was going though Danny's mind -)
>>As to private vs public, we are going to get similar issues with the
>>Point of Decision and Point of Enforcement of policies.
>>
>>One important place for the POA in the RA is as the start of the
>>chain of events that lead to the real world effect. Another is that
>>the POA acts as one place were policies must be applied. (I cannot
>>make up my mind exactly how POA relates POD and POE.) Of course, this
>>is but one place where policies are applied in the RA.
>>
>>Frank
>>On Aug 17, 2006, at 8:15 AM, Ken Laskey wrote:
>>
>>>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
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>__________________________________________________
>>>>>>>>Do You Yahoo!?
>>>>>>>>Tired of spam? Yahoo! Mail has the best spam protection around
>>>>>>>><http://mail.yahoo.com>http://mail.yahoo.com
>>>>>>>
>>>>>>>---
>>>>>>>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
>
>--
>
>---------------------------------------------------------------------------------
> / Ken
> Laskey \
> | MITRE Corporation, M/S H305 phone: 703-983-7934 |
> | 7515 Colshire Drive fax: 703-983-1379 |
> \ McLean VA 22102-7508 /
>
>----------------------------------------------------------------------------------
>
>
