Contract

A description of the messages and formats accepted and generated by a service. A service's contract is specified in a WSDL document that defines the interface and all connection-related information for that interface. A WSDL contract contains two sets of components: logical (or abstract) and physical (or concrete).

The logical components of the contract are those that describe the data types, message formats, operations, and interfaces for the services defined in the contract. Logical components are specified with the WSDL elements types, message, portType, and operation.