The portType section of the WSDL file (in this example, for LoanService) defines the ports to be used for the asynchronous service.

Asynchronous services have two port types. Each port type performs a one-way operation. In this example:

• One port type responds to the asynchronous process

• The other calls back the client with the asynchronous response

In the example shown below, the portType LoanServiceCallback receives the client's loan application request and the portType LoanService asynchronously calls back the client with the loan offer response.

<!-- portType implemented by the LoanService BPEL process -->
   <portType name="LoanService">
      <operation name="initiate">
         <input message="tns:LoanServiceRequestMessage"/>
      </operation>
   </portType>
<!-- portType implemented by the requester of LoanService BPEL process
for asynchronous callback purposes
-->
   <portType name="LoanServiceCallback">
      <operation name="onResult">
         <input message="tns:LoanServiceResultMessage"/>
      </operation>
   </portType>