How to identify weather the web service is sync or asyn?

Below are some simple ways to identify:

1. We can identify based on part types in WSDL.         

2. Asynchronous BPEL process is having two Port Types and each of them supports single operation.

3.  In asynchronous BPEL process two portTypes are defined and each portType corresponds to a single operation but in synchronous BPEL process we can see Single portType is defined for both operations.Single PortType and partnerLinkType instead of two.

4. Asynchronous BPEL Process has Recive and Callback Activity.

5. Synchronous BPEL process has reply activity instead of callback.