What's the difference between and in WSDL?

Question

Both and seem to define an operation and its message. I don\'t quite understand, why are they both necessary?

Answer 1

wsdl:portType goes with wsdl:operation i.e. we are in the realms of messages and xml as such

but wsdl:binding goes with soap:binding and soap:operation i.e. we are in the realm of encoding, addresses, headers and rpc

e.g. from : http://www.w3.org/TR/wsdl#_soap-b

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and from paragraph 3.2 all possible details about lower level communication stuff:

The SOAP Binding extends WSDL with the following extension elements:

    
        
        
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