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RE: Proposal for Resolution of 3564

From: Sverdlov, Yakov <Yakov.Sverdlov@ca.com>
Date: Wed, 25 Oct 2006 10:47:28 -0400
Message-ID: <ACE36C31EA815A4CBA7EBECA186C0D41DAF2E3@USILMS13.ca.com>
To: "Christopher B Ferris" <chrisfer@us.ibm.com>, "Yalcinalp, Umit" <umit.yalcinalp@sap.com>
Cc: <public-ws-policy@w3.org>
+1 to Umit with two modifications.


I would like to exclude from the proposal the following statement
because of the symmetric nature of message exchanges:

 "It is recommended that authors not utilize optional assertions for
outbound messages unless there is explicit, out of band mechanism
(currently such a mechanism is outside the scope of WS-Policy Framework)
that a client can use to indicate that the optional capability must be


Also I would like to change from:

"Optional assertion authors should explicitly state how the capability
that is enabled by the assertion would be engaged..."


"Optional assertion authors should explicitly state how the behavior
that is enabled by the assertion would be engaged..."




Yakov Sverdlov




From: public-ws-policy-request@w3.org
[mailto:public-ws-policy-request@w3.org] On Behalf Of Christopher B
Sent: Monday, October 23, 2006 3:08 PM
To: Yalcinalp, Umit
Cc: public-ws-policy@w3.org
Subject: Re: Proposal for Resolution of 3564



On the telcon 2 weeks ago, it was suggested during the discussion that
Umit's email may hold a key to 
unraveling the "tarball" ( I like to refer to it as the hairball, since
I have none). 

All were encouraged to review Umit's note and continue discussion on the
mailing list. 

I would like to resume the discussion on this topic this week. So,
please do review 
Umit's proposal and be prepared to discuss. If you have a better
suggestion, please 
do make a proposal and send it to the list. 


Christopher Ferris
STSM, Software Group Standards Strategy
email: chrisfer@us.ibm.com
blog: http://www.ibm.com/developerworks/blogs/page/chrisferris
phone: +1 508 377 9295 

public-ws-policy-request@w3.org wrote on 10/03/2006 07:00:09 PM:

> Folks, 
> As we have decided to divide the understanding the framework 
> concerns from the assertion development concerns, below find the 
> proposal for Optional Assertions as we would like to propose for the
> Author's Guidelines Document. 
> In this proposal, it is assumed that the Primer will introduce an 
> example as it does today and the Assertion Guidelines document will 
> refer to the example by further guidance and illustration of 
> pitfalls. These pitfalls that are covered below were also noted in 
> the creation of this issue [3564] 
> In developing this proposal, I realized that we have a separate 
> issue with the Primer document, namely the choice of MTOM capability
> as an example for optional assertions. I am creating a new issue for
> that so it can be tackled separately. The current writeup, as it 
> refers to the Primer, assumes that such an assertion exists but the 
> text can easily be changed to refer to WS-RMP, or any other 
> assertion that is currently in practice to be used with 
> optional="true" marker. Therefore, please keep that in mind while 
> reading this proposal. 
> Thanks, 
> --umit 
> [3564] http://www.w3.org/Bugs/Public/show_bug.cgi?id=3564 
> Section 5.7 Optional Policy Assertion: 
> Optional assertions represent behaviors which may be engaged by a 
> consumer. When using the compact authoring form for assertions, 
> behaviors are marked by using wsp:optional attribute that has a 
> value, "true". During the process of normalization, the runtime 
> behavior is indicated by two policy alternatives, one with and one 
> without containing the assertion. In a consumer/provider scenario, the

> choice of engaging the runtime behavior is upon the consumer although 
> the provider is capable of engaging the runtime behavior. 
> The Primer document contains an example that proposes MTOM as an 
> optional behavior that can be engaged by a consumer. The primer 
> proposes that this assertion identifies the use of MIME 
> Multipart/Related serialization for messages to enable a Policy-aware 
> clients to recognize the policy assertion and if they select an 
> alternative with this assertion, they engage Optimized MIME 
> Serialization for messages. 
> The semantics of this assertion declare that the behavior is reflected

> in messages: they use an optimized wire format (MIME Multipart/Related

> serialization). Note that in order for an optional behaviors to be 
> engaged, the wire message that would utilize the specific assertion 
> must be self describing. For example, an inbound message to a web 
> service that asserts MTOM, must evaluate, the protocol format of the 
> message to determine whether the incoming message adheres to the 
> Optimized MIME Serialization. By examining the message, the provider 
> can determine whether the policy alternate that contains the MTOM 
> assertion is being selected. 
> Assertion authors should be aware that optional behaviors, like 
> utilizing optional support for Optimized MIME Serialization require 
> some care. 
> + Since optional behaviors indicate optionality for both the provider 
> and the consumer, behaviors that must always be engaged by a consumer 
> must not be marked as "optional" with a value "true" since presence of

> two alternatives due to normalization enables a consumer to choose the

> alternative that does not contain the assertion, and thus making the 
> behavior not being engaged in an interaction. 
> + As demonstrated in the MIME optimization behavior, behaviors must 
> be engaged with respect to messages that are targeted to the provider 
> so that the provider can determine that the optional behavior is 
> engaged. In other words, the requirement of self describing nature of 
> messages in order to engage behaviors must not be forgotton with 
> regard to the client's ability to detect and select the alternative if

> it is to participate in the exchange. It is recommended that authors 
> not utilize optional assertions for outbound messages unless there is 
> explicit, out of band mechanism (currently such a mechanism is outside

> the scope of WS-Policy Framework) that a client can use to indicate 
> that the optional capability must be engaged. 
> + When optional behaviors are attached with only one side of an 
> interaction, such as an inbound message of a request-response, the 
> engagement of the rest of the interaction will be undefined. For 
> example, if a request-response interaction only specified MTOM 
> optimization for an inbound message, it would not be clear whether the

> outbound message from the provider could also utilize the 
> behavior. Therefore, the assertion authors are encouraged to consider 
> how the attachment on a message policy subject on a response message 
> should be treated when optional behaviors are specified for message 
> exchanges within a request response for response messages. Leaving the

> semantics undescribed may result in providers making assumptions 
> (i.e. if the incoming message utilized the optimization, the response 
> will be returned utilizing the MTOM serialization). Similarly, if 
> engagement of a behavior is only specified for an outbound message, 
> it may be necessary to describe the semantics if the incoming messages

> also utilized the behavior. WS-RM Policy currently allows the 
> incoming messages to utilize WS-RM protocol to be engaged although the

> assertion may only appear on an outbound message in a request 
> response. 
> + Optional assertion authors should explicitly state how the 
> capability that is enabled by the assertion would be engaged when they

> are designing their assertion, whether by specific headers or some 
> other means. 
> ---------------------- 
> Dr. Umit Yalcinalp 
> Architect 
> NetWeaver Industry Standards 
> SAP Labs, LLC 
> Email: umit.yalcinalp@sap.com Tel: (650) 320-3095 
> SDN: https://www.sdn.sap.com/irj/sdn/weblogs?blog=/pub/u/36238 
> -------- 
> "First they ignore you, then they ridicule you, 
> then they fight you, then you win." Gandhi 
Received on Wednesday, 25 October 2006 14:47:51 UTC

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