The image shows a diagram of a synchronous interaction between two BPEL processes. The following actions take place:

1. The first BPEL process, with its bpel.xml deployment descriptor, has an invoke activity that defines a call service.

2. The call service invoke activity sends its resquest to the second BPEL process, through a WSDL client partner link. The WSDL client partner link defines the interaction.

3. The second BPEL process (with its bpel.xml deployment descriptor) accepts the request by using a receive activity.

4. The second BPEL process then uses a reply activity to send a response back to the first BPEL process, by way of the WSDL client partner link.