What is the interface

The interface is an abstract model of the service:

<interface name="Service1HttpGet">
  <operation name="getResult"
      <input message="s0:getResultHttpGetIn">
         <part name="uri" type="xsd:anyURI"/>
      <output message="s0:getResultHttpGetOut">
         <part element="s0:getResultResponse"/>

WSDL 1.2 improves interfaces with inheritance: no overloading (if two operations have the same qname, then their components must be equivalent, i.e. the abstract model are equals).

Issue: Should we introduce properties?