In an asynchronous interaction, a client sends a request to a service and waits until the service replies. The following example shows the portType and operation part of the BPEL process WSDL file for this environment.

. . .
<wsdl:portType name="BPELProcess1">
      <wsdl:operation name="process">
         <wsdl:input message="client:BPELProcess1RequestMessage"/>
      </wsdl:operation>
</wsdl:portType>

. . .
<wsdl:portType name="BPELProcess1Callback">
      <wsdl:operation name="processResponse">
         <wsdl:input message="client:BPELProcess1ResponseMessage"/>
      </wsdl:operation>
</wsdl:portType>

Figure 5-3 provides an overview.