WSDL - soap:operation/@soapAction - needs to be unique?

In WSDL1.1, does each binding/operati开发者_如何学运维on/soap:operation/@soapAction have to be unique inside it's containing binding? If not, how does the SOAP/WSDL server know which "matching" operation to invoke?

I'm pretty sure the SOAP Action has to be unique, it's the part of the request (for HTTP transports, it's in the form of an HTTP header) which uniquely identifies the operation. Essentially, the SOAP Action is the URI of the operation.

Having said that, in many cases the SOAP action header is redundant, since the type of the SOAP payload is often enough to uniquely identify the target operation.