RE: [soa-rm] Revisiting: Definition of Service Orientation and how it relates to SOA

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

Ken - - Agree. I keep coming back to the idea that it's the addition of context info and the ability to process it that makes the difference.  I am convinced the "why?" is to permit exploitation of the Internet across organizational boundaries; the "how?" is by adding context info (descriptive metadata) to the service components, and the ability for negotiation of how the components can be combined. The ability to negotiate semantics, policy/contract and protocol supports diversity and choice in the global Internet "market" environment.
 
martin
 

________________________________

From: Ken Laskey [mailto:klaskey@mitre.org]
Sent: Thu 5/26/2005 10:51 PM
To: Smith, Martin
Cc: soa-rm@lists.oasis-open.org
Subject: Re: [soa-rm] Revisiting: Definition of Service Orientation and how it relates to SOA



Martin,

As I started answering, I realize the differences are
(1) we are combining many aspects that I do not believe have all been 
previously done together and
(2) we are aiming towards a grand vision that is more dynamic than 
envisioned before but for which it is not clear that the underlying 
technology is really mature.

Considering (1), there is the distributed nature of the services and 
the fact that these are intended to be used from their distributed 
location.  This is distinguishing from OO but not necessarily CORBA.  
There is also the idea of orchestration, but that also needs to be 
dynamic to be different than building a more traditional application 
using parts you have previously identified. There are other things we 
should list but the question is whether one of the differences is this 
is the first time this set has been done together.

Considering (2), a SOA is supposed to be much more dynamically 
composable.  Eventually (I'm not convinced it happens much now) the 
distributed interfaces will be discoverable and be able to be used 
without traditional integration handshaking.  This indicates a level of 
semantic negotiation that I am not sure we yet know how to do.   Also, 
we are looking to collect information from diverse discoverable 
sources, but I'm not sure we know how to consistently combine 
information just from the descriptions of the services used to retrieve 
the information.  Orchestration also should be dynamic but that 
indicates an advanced level of decision support.  Then there is the 
question of how to handle uncertainty and incomplete and/or 
inconsistent data.  This possibly also extends to incomplete and/or 
inconsistent service descriptions.

So part of the question when we talk about why SOA is different is how 
much do we draw on the grand vision?  And if we include too much of the 
grand vision, do we lose an incredulous audience?

Ken



On May 26, 2005, at 8:28 PM, Smith, Martin wrote:

> Ken- - Agree that these are characteristics of SOA, but I'd say that 
> they are mostly not DISTINGUISHING characteristics.  Modularity and 
> re-use and interchangeability/standards are themes that have been 
> developed over a long period of time.  OO certainly promotes both.  So 
> does component-based AD. SOA incorporates tehse principles, for sure.
>
> But what's the difference between component-based AD and 
> services-oriented AD?  What does SOA add to CBD?
>
> Martin
>
>
> ________________________________
>
> From: Ken Laskey [mailto:klaskey@mitre.org]
> Sent: Thu 5/26/2005 6:04 PM
> To: soa-rm@lists.oasis-open.org
> Subject: Re: [soa-rm] Revisiting: Definition of Service Orientation 
> and how it relates to SOA
>
>
>
> ... snip
>
> For more flexibility, I don't just want one service to take the
> undesirable work off my hands, I want a choice.  And because I know
> that my choice may change depending on circumstances, I want to
> dynamically make the choice.  (Don't you hate it when you get a wedding
> invitation and you have to decide what you want to eat a month from
> now?)  Or even if not with zero latency, I want to be able to easily
> change my choice. I need services to be interchangeable.
>
> And I don't want my choice to lock me into a whole set of other
> choices.  I go to buy a car and I want airbags but I can only get these
> if I get power windows!  I want an interoperability of my choices along
> with interchangeability of parts that I choose.
>
> Finally, what is the polar opposite of services?  The polar opposite is
> NIH, not invented here.  Service orientation says I want to do as
> little by myself as possible.  There are people out there who are
> smarter than me and do some things better than me and I'm going to make
> use of that expertise whenever I can.  That takes a certain level of
> trust because I am giving up control of the details so I can spend my
> energy on the things I can best provide to others.  The opposite is
> assuming everything I need to do is unique and no one can do any of it
> as well as me (or as well as someone I would directly control).  Now
> when you have opposites, you usually have degrees between them.
>
>
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Ken Laskey
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