WSDL binding difference

Question

In WSDLs generated by AXIS and CXF, there are always defined three binding elements.
As reported in the following sample WSDL describing a temperature conversion service:

<wsdl:binding name="ConverterSoap11Binding" type="ns:ConverterPortType">
<soap:binding transport="http://schemas.xmlsoap.org/soap/http" style="document"/>
<wsdl:operation name="celsiusToFarenheit">
<soap:operation soapAction="urn:celsiusToFarenheit" style="document"/>
<wsdl:input>
<soap:body use="literal"/>
</wsdl:input>
<wsdl:output>
<soap:body use="literal"/>
</wsdl:output>
</wsdl:operation>
<wsdl:operation name="farenheitToCelsius">
<soap:operation soapAction="urn:farenheitToCelsius" style="document"/>
<wsdl:input>
<soap:body use="literal"/>
</wsdl:input>
<wsdl:output>
<soap:body use="literal"/>
</wsdl:output>
</wsdl:operation>
</wsdl:binding>
<wsdl:binding name="ConverterSoap12Binding" type="ns:ConverterPortType">
<soap12:binding transport="http://schemas.xmlsoap.org/soap/http" style="document"/>
<wsdl:operation name="celsiusToFarenheit">
<soap12:operation soapAction="urn:celsiusToFarenheit" style="document"/>
<wsdl:input>
<soap12:body use="literal"/>
</wsdl:input>
<wsdl:output>
<soap12:body use="literal"/>
</wsdl:output>
</wsdl:operation>
<wsdl:operation name="farenheitToCelsius">
<soap12:operation soapAction="urn:farenheitToCelsius" style="document"/>
<wsdl:input>
<soap12:body use="literal"/>
</wsdl:input>
<wsdl:output>
<soap12:body use="literal"/>
</wsdl:output>
</wsdl:operation>
</wsdl:binding>
<wsdl:binding name="ConverterHttpBinding" type="ns:ConverterPortType">
<http:binding verb="POST"/>
<wsdl:operation name="celsiusToFarenheit">
<http:operation location="celsiusToFarenheit"/>
<wsdl:input>
<mime:content type="application/xml" part="parameters"/>
</wsdl:input>
<wsdl:output>
<mime:content type="application/xml" part="parameters"/>
</wsdl:output>
</wsdl:operation>
<wsdl:operation name="farenheitToCelsius">
<http:operation location="farenheitToCelsius"/>
<wsdl:input>
<mime:content type="application/xml" part="parameters"/>
</wsdl:input>
<wsdl:output>
<mime:content type="application/xml" part="parameters"/>
</wsdl:output>
</wsdl:operation>
</wsdl:binding>

what's the difference between these three kind of bindings ?

Answer 1

First see this diagram wsdl structure

Bindings: Read

So there are three ways (message and transport protocol) to access your web service i.e.

ConverterSoap11Binding (Message Protocol: SOAP 1.1)

ConverterSoap12Binding (Message Protocol: SOAP 1.2)

ConverterHttpBinding (Message Protocol: HTTP POST)

In all above binding transport protocol will be HTTP (as in your service address).