about NCOIC Service Interface Pattern

2.4.9 Interface Stability {SOA}[1]

To achieve interface stability through design, the following SOA structure requirements apply:

a. Service Level Agreements (SLA)s or equivalently named contractual instruments shall contain Explicit Operational Agreements.

b. Explicit Operational Agreements shall contain interface definitions.

c. Explicit Operational Agreements should contain a governance policy

d. The authentication and authoritization process for who can examine published contracts shall be standards based..

e. Interface artifacts shall be published in a registry/repository or other object, e.g., ESB.

f. Interface Definitions shall be standards based, e.g., WSDL, XSD, etc.

g. The SLA shall contain performance characteristics associated with each interface.

h. SLAs shall be maintained between the Provider and individual Consumers or classes of Consumer

i. Versioning processes may be contained in a separately defined governance process. Governance principles are described in the NCSF. A NCOIC governance pattern is under consideration.

[1] SOA (Service Oriented Architecture), NC(net centric), & SW(software) are solution categories. They are used here to map the solutions in sections 2.4 and 2.5 to these categories. See Appendix C, section 5.3 for a summary of this mapping.

To my taste, copied content has almost nothing to do with "Interface Stability". I think that stability of service interface is about how the interface can work in the changing environment, changing behaviour model and related messages. For example, Interface Definitions shall be standards based, e.g., WSDL, XSD, etc" does not contribute into the stability, IMO, because someone may (should not be restricted from) publish (ing) a non-standardised but immutable (100% stable) interface. Moreover, common (not thought through) use of WSDL leads to constant changes if the interface, i.e. minimal stability. In the essence, it is not a standardisation that important, but the usability pattern is important. And the latter has escaped aforementioned list.

An example of interface stability: 'adding or removing data elements of the exchange messages should not result in the change of interface'. I can say the same thing regarding the operations and use WSDL (in a smart way) to implement this.

Anyway, thank you very much for such interesting material.

- Michael

-----Original Message-----
From: Rex Brooks <rexb@starbourne.com>
To: mpoulin@usa.com; 'Ken Laskey' <klaskey@mitre.org>
Sent: Wed, Mar 23, 2011 3:30 pm
Subject: Re: [soa-rm-ra] meeting time conflict

Hi Guys,

I didn't send the redline version and waited for this latest clean version of the NCOIC Service Interface Pattern. I'm not suggesting you go through this in detail to ensure that the principles espoused in Sections 4 and 5 are actually taken up in this document, but you could if you wanted to do that. However, I think this provides a fairly good example of what can be expected of "Testing" with "Management" in mind. Please do not redistribute despite the fact that it is not strictly disallowed. I send it to you two because I think it bears on finishing up your work. Sorry if it's a bit late. Reminder: This is still a work in progress and this is not yet approved, but it is likely to be approved.

Cheers,
Rex

On 3/23/11 4:05 AM, mpoulin@usa.com wrote:

Hi Folks,

I will have a conflict of meetings today: I will be able (now) to participate in the first and the last 30 min time-windows only. Please, plan my presentation on the Management Model accordingly.

Sorry,

- Michael

-- 
Rex Brooks
President, CEO
Starbourne Communications Design
GeoAddress: 1361-A Addison
Berkeley, CA 94702
Tel: 510-898-0670

soa-rm-ra message

2.4.9 Interface Stability {SOA}[1]