RE: [soa-rm] When Is An SOA Really An SOA?

["Smith, Martin" <Martin.Smith@DHS.GOV>]

John & al. - - 

I have been thinking about this question from a slightly different
angle, namely "why do we all seem to think we need this 'SOA' thing?"
I'm guessing that if we can get at purpose, then that will clarify the
"essential definition" question.

Here's a first effort at what I hope might eventually be part of our
Introduction:

"The SOA concept has emerged in response to the need for an approach to
application architecture that is well adapted to the Internet
environment. The Internet has revolutionized personal communications
with e-mail, and "B-to-C" transactions with the World-Wide Web.
Following the exploitation path of other technologies, the Internet may
be expected to have a similar revolutionary effect on "B-to-B"
transactions - - automating system-to-system exchanges - - and this
domain may eventually be several times larger in scale that the "B-to-C"
space. 

The characteristics of the Internet environment to which the SOA concept
responds are:

	1.  Multiple management domains.--Business or other entities "on
the 'Net" each have their own set of policies and procedures, and they
are legal peers so there is little or no "top down governance" in the
environment;
	2.  Heterogeneous technologies, semantics and processes;
	3.  A very large and dynamic "marketplace" of potential service
providers and consumers.--Unlike the environment within a single
organization, there may be many alternative providers of a computing
service, and available services may change on a minute-by-minute basis;
	4.  Lack of standard context.--Within a single organization,
there is normally a body of "well-known" information about what
resources are available, how they may be obtained, what standards or
conventions they follow, specific interface details, reliability of the
resource, payment requirements, if any, etc. In the environment of a
single computer, the unknowns are even fewer.  Because of the size and
diversity of the Internet, obtaining this information is a much larger
problem.
	5.  Lack of infrastructure services.--The Internet provides some
basic services, but on a "best-efforts" basis. Thus issues like
quality-of service and security require must be addressed more
explicitly than in single-computer or local-network environments. 

Most application architectures that call themselves "SOA" provide a
solution to these issues of the Internet environment. There is nothing
to prevent implementing an SOA within a local network, on a single
computing platform, or even in a non-technical environment like a human
household, but the need for SOA is driven by the opportunity for
exploiting the worldwide connectivity provided by the Internet."

Martin









-----Original Message-----
From: John Harby [mailto:jharby@gmail.com] 
Sent: Thursday, May 05, 2005 12:05 PM
To: soa-rm@lists.oasis-open.org
Subject: Re: [soa-rm] When Is An SOA Really An SOA?

This seem to be an issue for defining "Reference Model". Does this
reference model provide a litmus test for architectures to determine
whether or not they follow SOA?

On 5/5/05, Chiusano Joseph <chiusano_joseph@bah.com> wrote:
> This question has been on my mind for quite some time, and I would
like now
> to put it in the context of our in-process RM.
>  
> In the past, I have pondered the following more specific question
(please
> note that this is all scoped to Web Services-based SOA for ease of
> explanation): 
>  
> If I have 2 Web Services that communicate, do I have an SOA? 
>  
> We can say "certainly not!". One can do point-to-point integration
with Web
> Services just as easily (to a certain degree) as without, with
redundant Web
> Services rather than shared Web Services (a violation of one of the
> foundational tenets of SOA, which is shared services).
>  
> Now let's say that we have 2 Web Services that each conform to the SOA
> Architectural Model in Figure 1 of our most recent draft. There is a
data
> model, a policy, a contract, etc.
>  
> Add to that our definition of SOA on line 470, in which we (correctly)
state
> that SOA is a form of Enterprise Architecture, which (at least in my
mind)
> implies enterprise-level benefits.
>  
> Q: Given the last scenario above (2 Web Services that each conform to
the
> SOA Architectural Model ) and our definition of SOA: Is this scenario
> large-scale enough that it *really* meets our definition? IOW, how
> large-scale does an "instance" that conforms to our RM have to be to
yield
> benefits on an enterprise scale? Do we need to stipulate something
regarding
> this for our RM?
>  
> Joe
>  
> 
> 
> Joseph Chiusano
> 
> Booz Allen Hamilton
> 
> Visit us online@ http://www.boozallen.com
>  
>