"EDA is an architecture; CEP is a technique..."
Jack van Hoof, who has written extensively on all things EDA, says there have been one too many instances in which the terms EDA (Event Driven Architecture) and CEP (Complex Event Processing) have been used almost interchangeably. He provides a clarification:
"CEP is a way of processing messages (fair enough to name these messages "events").... But EDA is about how business events drive the overall architecture of the IT-systems and it is about how these events should be modeled. EDA it is not primarily about the ability to process and correlate streams of thousands of messages per second..."
Just as SOA addresses the architectural aspect of service orientation for the business, EDA addresses the architectural aspect of how events should be processed for the business, Jack says. "CEP is just one among these aspects." Please, he adds, EDA "EDA does not only deal with complex events (correlations) but also with simple events."
"So CEP is not EDA, EDA is more than CEP. Promoting CEP as being EDA is far too simple. And yet that is what is happening in the current IT space."