A BPEL process depends upon WSDL extensions that are unique to BPEL. Process Developer can create these extensions automatically if they do not exist in your WSDL files. The extensions are partner link types, properties, and property aliases.
A partner link type defines the roles played by a service and the port type provided by the service. For details, see
Partner Link Type
Properties and property aliases are significant for correlating a group of messages in a process and can also be used for any process variable. For more information, see