The challenge is far more difficult than with the conventional enterprise transaction IT mastered long ago when it tracked session state and rolled back entire transactions if any piece failed. To make matters worse, the transaction has to produce a response in near real time, often while the customer is still online. Rather than thinking of this situation as conventional transaction management on a broader scale, IT managers increasingly view this as a combination of workflow management and application integration. But even these terms don't adequately describe the problem. This really isn't workflow.
Workflow processes are serial in nature, which can be slow.
This requires high performance and for that you can't work serially. This substantially complicates the problem. There has to be an over-riding way for all the pieces to communicate so that the larger activity can be orchestrated. You don't necessarily need to know how the various systems do their individual jobs. But you do need to know what each system is supposed to do.