This figure includes seven rectangles, some of which are connected by arrows.

At the top left of the figure is the "Start BPEL Engine" rectangle.

The middle part of the figure includes three rectangles organized horizontally. From left to right, the labels for these figures are:

An arrow starts from the Start BPEL Engine rectangle at the top left of the figure and points to the Access MDS and load Composites rectangle. An arrow starts from the Access MDS and load Composites rectangle and points to the Target BPEL Process to BPEL engine rectangle. An arrow starts from the Target BPEL Process to BPEL engine rectangle and points to the Wait for requests to components rectangle.

Below these three rectangles are two rectangles organized horizontally. From left to right, their labels are:

An arrow starts from the Wait for requests to components rectangle above and points to the Place request in Dispatcher's queue rectangle. An arrow starts from the Place request in Dispatcher's queue rectangle and points to the Process unit of work rectangle.