I agree that EDA adds a few more principles to an architecture. Where 
we may disagree is in assuming EDA is about one-way communication and 
only about pub/sub. An architecture following EDA principles may 
choose to use one-way comm (fire and forget) in some scenarios (e.g. 
in cases where it doesn't matter if the event doesn't make it), and 
may choose to use pub/sub as an implementation technique (this is but 
one way to distribute events), but neither are necessary for EDA.

As always, just my 2 bits.

-Rob

--- In [email protected], "Paul 
Fremantle" <[EMAIL PROTECTED]> wrote:
>
> I have a simple view of SOA and EDA:
> 
> SOA is about devolving interfaces management and definition to
> endpoints. In an SOA, its not my responsibility to understand your
> interface, its your responsibility to produce an interface that 
anyone
> (including me) can handle. So an SOA offers a set of services that
> have uniform interfaces that can be accessed by anyone.
> But its still required that a service provider advertises their
> services and a service consumer explicitly calls those interfaces. 
So
> the wiring is not devolved.
> 
> In EDA, the model goes a stage further: not only are the interfaces
> defined, but their is a wider definition (the topic space) which
> identifies the overall structure of all the
> interfaces/services/event-types. And in this model, the wiring is
> devolved - its up to anyone who needs access to information to
> subscribe themselves to that topic.
> 
> Of course in order to make this work, the model also needs
> simplification. SOA is effectively a simplification by forcing
> everyone to use uniform interfaces. EDA forces an even simpler 
model -
> everything must be one-way/event-based and it is up to the
> event-consumer to understand what to do with that event.
> 
> On a related topic, I've been involved in an SOA/EDA project and we
> came across an interesting puzzle/problem with interfacing EDA with
> complete black-box systems. I wrote about it here:
> http://pzf.fremantle.org/2008/09/interesting-problem-in-event-
driven.html
> 
> Paul
> 
> -- 
> Paul Fremantle
> Co-Founder and CTO, WSO2
> Apache Synapse PMC Chair
> OASIS WS-RX TC Co-chair
> 
> blog: http://pzf.fremantle.org
> [EMAIL PROTECTED]
> 
> "Oxygenating the Web Service Platform", www.wso2.com
>


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