Re: NEW ISSUE: New Attribute keyword to identify 'local' policies #3721


It was mentioned by Fabian on the call today that different  
assertions can have different properties, and I think this is where  
we are heading with wsp:local/wsp:advisory (alternative names for the  
same concept and attribute)

In general an assertion present in a policy assertion means that the  
client MUST understand that assertion and that the provider WILL  
support it. This is regardless of whether the assertion has a wire  

Using wsp:optional enables policy alternatives to be easily created,  
either requiring and asserting the assertion and not.

However there are cases where wsp:optional is not what is desired,  
and where wsp:local/wsp:advisory is needed.

The use case is that a provider should be able to state an assertion  
that will be in effect, but it obeys the following properties:

1) It can safely be ignored by web service client, even though true.  
The provider is making no obligation to the client. It has no  
essential impact on a contract between client and provider.

An example is an assertion that server logging is performed (e.g.  
clients might not care about it, but it is *not* optional in the  
sense that the server *will* do it).

1a) Assertions that imply mutual contract between client and provider  
cannot be wsp:local/wsp:advisory. These include

+ Assertions that impact wire formats
+ Assertions that define quality of service (service level  
agreements), quality/reliable messaging.

2) The client can choose to include or not in intersection operation,  
depending on interest.
Without wsp:local/wsp:optional all assertions MUST be included in  
intersection operation.

3) This is additional information that a client might wish to consider.

we need to distinguish optional for agreement of a contract with or  
without an asserted requirement/capability and informational items  
that are not necessarily optional.

regards, Frederick

Frederick Hirsch

On Oct 4, 2006, at 4:30 AM, ext Sergey Beryozkin wrote:

> Hi
> Reference to the thread[1] is misleading IMHO.
> I was stating from the start that a proposed wsp:local was nothing  
> to do with what is discussed in that thread. The semantics of  
> wsp:local are : mark assertions which *must be ignored* by a  
> requester. That is it, no more semantics...
> Thanks, Sergey
> ----- Original Message -----
> From: Yalcinalp, Umit
> To:
> Sent: Tuesday, October 03, 2006 11:44 PM
> Subject: Re: NEW ISSUE: New Attribute keyword to identify 'local'  
> policies #3721
> There has been a lot of discussion on Issues 3721 and 3564. I am  
> posting this response to this thread in order to illustrate why  
> there are two separate issues that need to be tackled  
> independently. However, they are NOT the same issue. Utilization of  
> optional assertions is a separate concern and those issues must not  
> be lumped together.
> Please find some comments in a different thread that explains why  
> there are two separate issues here for the details [1].
> Thanks,
> --umit
> [1] 
> 0016.html
> ----------------------
> Dr. Umit Yalcinalp
> Architect
> NetWeaver Industry Standards
> SAP Labs, LLC
> Email: Tel: (650) 320-3095
> SDN:
> --------
> "First they ignore you, then they ridicule you,
> then they fight you, then you win." Gandhi

Received on Wednesday, 4 October 2006 19:03:57 UTC