RE: [soa-rm-ra] Groups - Modification of Policy_Contract_Business diagram (OASIS_Policy-Contract_Diagram.JPG) uploaded

["Jones, Steve G" <steve.g.jones@capgemini.com>]

I'm not sure if I will help or hinder here, but from an outsourcing
perspective I'd classify the three (policy, SLA and contract) as being
different for a service.

The policy is what we say must happen
The SLA is the bounds within which it must happen
The contract is what policies and SLAs apply and what happens when they are
broken.


So as an example,  the policy is that we must authenticate the user against
the corporate directory.  The SLA is that this must be done within a 1/10th
second and the contract says that the policy applies and that SLA violation
is an "amber" issue and should be flagged.

As another example, there is a "WidgetPurchase" service which has policies
that say that messages must be reliably sent over a secure communication
mechanism.  One SLA says that WidgetPurchase must be available "five nines"
another says "when it feels like it".  The contract is the thing that says
that for a given consumer of the service that the reliable messaging policy
doesn't apply, security does, and their SLA is "when it feels like it", this
is the "pleb" contract.  The "consul" contract is the one that has
reliability and security as policies and five nines as the SLA.

So from a business perspective they are often treated as different entities.

Steve

PS If I'm not helping just tell me to go away again :)

-----Original Message-----
From: Francis McCabe [mailto:frankmccabe@mac.com] 
Sent: 05 May 2007 19:12
To: Francis McCabe
Cc: michael.poulin@uk.fid-intl.com; soa-rm-ra@lists.oasis-open.org
Subject: Re: [soa-rm-ra] Groups - Modification of Policy_Contract_Business
diagram (OASIS_Policy-Contract_Diagram.JPG) uploaded

A quick follow up,

It is also not fair to say that a contract is *more* than a policy.

The distinction between them refers to the origin of the constraint:  
a policy originates with a single participant (or proxy etc.) a  
contract originates in an agreement between participants.


On May 5, 2007, at 11:07 AM, Francis McCabe wrote:

> Again, I need to get completely clear on something:
>
> It is *not* reasonable to state:
>
> Contract is not only more than a Policy but also more than a SLA
>
> In some limited areas, you may constrain SLAs to focus on things  
> like bandwidth etc., but other businesses will use SLAs to govern  
> things like business opening hours, response times for service and  
> so on.
>
> So, again, I do not yet see a particularly strong case for  
> distinguishing SLAs from contracts.
>
> Certainly for our architecture we need to be as encompassing as  
> required to support business via services, not simply to build yet  
> another IT infrastructure.
>
> Frank
>
> On May 5, 2007, at 10:53 AM, michael.poulin@uk.fid-intl.com wrote:
>
>> I have a strong impression that in our March discussion about  
>> Contract & Policies we  have agreed that Contract is not only more  
>> than a Policy but also more than a SLA. The SLA is explicitly  
>> measurable (run-time) set of service attributes/characteristics/ 
>> actions while a Contract can contain Commitments of the contract  
>> participants that 1) are not visible through the service  
>> interface; 2) may be not measured at run-time. I guess, it is the  
>> time for me to show my version of a Service Contract Template we  
>> are discussing in my organisation ( I will be able to do it not  
>> earlier than on Tuesday next week).
>>
>> I have described an example of such contract  in my article "Does  
>> Web Services makes a Service for SOA?" In particular, a service  
>> provider was obliged to gather audit info on all actions requested  
>> by particular client and failed in it because its database was not  
>> available for some time and several audit messages got lost.
>> If we are building high level RA, we cannot discard the scenario  
>> I've just described.
>> That is, Contract is an agreed container of all service related  
>> actions performed by the provider's SW system(s). With such  
>> definition, I do know what to do in IT with Service Contract.
>>
>> Nevertheless, I am still unclear on Contract-Policy relationship  
>> issue...
>>
>> - Michael
>



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