Is CEP a pre-requisite for EDA or SOA?

| by Dilip Krishnan Follow 0 Followers on Nov 11, 2008. Estimated reading time: 2 minutes |

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In a post Jack Van Hoof  compared CEP and EDA and how they relate to an SOA. He said

CEP (Complex Event Processing) correlates multiple messages within given time frames. EDA is an architectural approach to model information systems from a business event perspective. EDA differs from SOA by its focus. SOA puts services at the center of the model and EDA does so with business events. The SOA-approach tends to result in a synchronous communication style and the EDA-approach in an asynchronous communication style.

He believes that the market does not understand EDA  and explains how CEP is fundamentally different from EDA; that CEP is a tool and EDA is an architecture

CEP is not about business events by definition. CEP is a technique to process message streams. These messages do not need to represent business events. A business event is something that happens (change of state) where your business has planned to react upon in a predefined way. A business event is represented by a message, but not all messages are representations of business events. CEP is about messages, EDA is about business events. CEP can be used to implement EDA. You might say: EDA is CEP at the business level.

In response, Giles Nelson of Progress Apama, elaborated on the relationship with SOA, EDA and CEP with several key points. Joe McKendrick’s echoed a similar point of view in his post Why 'Event Driven Architecture' is more than Complex Event Processing. So also Udi Dahan, who illustrated, with a nice order-to-cash process example, how these concepts play together in a real world business problem. He summarized his position with the following remark

CEP, while being a challenging engineering field, and managing the technical risks around it necessary for a project to succeed in some circumstances, and really shines when used under the SOA/EDA umbrella, it should not be taken by itself and used at the topmost architectural levels.

Jack concludes his post with emphasis on the importance on EDA saying  “I think EDA will definitely and radically change the way we currently look at business applications, including SOA”.

We have covered this debate in the past from an architecture perspective aswell. There appears to be a lot of confusion on how CEP, SOA and EDA relate to each other and its largely because of the vendors. It would be interesting to get a perspective on how these technologies are being adopted in the enterprise. What is the role of CEP in your enterprise? and how are they being used in EDA and SOA intiatives?

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SOA, SOA 2.0 and EDA Defined and Illustrated with CEP/EP by Tim Bass

Hello Dilip,

The relationship between CEP, SOA and EDA was presented (at least) as far back as September 26, 2006 in the presentation, SOA, SOA 2.0 and EDA Defined and Illustrated with CEP/EP, located here:

Regarding the "confusion," we briefed this as far back as March of 2006. You can find the background here:

Also, I recommend you read this follow-up post, CEP is Not a Just a Technology and Not Just a Tool, here:

Cheers and thanks for calling out our blog post!

Yours sincerely, Tim

PS: I have posted around 25 CEP/EP related presentations on SlideShare (includes EDA/SOA/BPM, relationships, etc). Kindly refer to this post for more info:

They are complementary, thus they are not the same ... by Hamza BENMANSOUR

David Luckham wrote two interesting posts on his blog about it :



Coming to Devoxx? by Paul Fremantle

I'll be talking about this at Devoxx

If anyone is going to be there let me know - this could make for interesting bar discussions!


Re: SOA, SOA 2.0 and EDA Defined and Illustrated with CEP/EP by Tim Bass

Dear Dilip,

I just noticed that it takes "too many clicks" to get to my online collection of CEP/EP slides (above in PS:) so, not to cause your readers to waste their valuable time clicking, here is a "one click link" directly to the slides:

Yours faithfully, Tim

Re: SOA, SOA 2.0 and EDA Defined and Illustrated with CEP/EP by Dilip Krishnan


Thank you for pointing to resources, It helps our readers get a further understanding of this technology space.


Re: SOA, SOA 2.0 and EDA Defined and Illustrated with CEP/EP by Alex Vasseur

I believe that although lot of people had exposure with SOA in those past 5 years, only few had exposure to EDA and even less had hands on experience with CEP deployments. I have put things in perspective at in a simple way using an "is an ESB a pre requisite to SOA" analogy - to which I am sure we can hear different voices even today.
For folks interested with simple hands on CEP - check out for a number of technical presentations and articles with sample code on CEP based on Esper. A good place to start for a wider view is also likely


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