Why do we need SOA? (proposal for Introduction text)

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

List - - 
 
I sent essentially this same message in the thread  "[soa-rm] When Is An SOA Really An SOA?"  a while back, but got no response.  Thought I'd try again to see if no-one noticed it or no-one liked it . . .
 
I'm proposing we include something like the following in the Introduction.  As several people have observed, we all tended to jump right in to the details of "what is an SOA" without nailing down the answer to the "why should I [the reader] care?" question.  As we learned in the f2f discussion, many of us on the TC care because it's our job to explain to others why we all seem to think we need this 'SOA' thing (other than that it keeps being in the news!)  I'm guessing that if we can understand why SOA has become a buzzword, we'll  clarify the "essential definition" question.

So, here's what I think is driving SOA: 

"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. 

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 
>  
>